Control of surface polymerization rate by formulation of reaction compositions

Abstract

Methods for controlling polymerization rate in relation to the formation of surface polymers on a substrate as well as systems for carrying out the methods are disclosed herein. The formulation of reaction compositions so as to provide a controlled rate of surface polymeri­zation are disclosed.

Description

[0001] Control of Surface Polymerization Rate by Formulation of Reaction Compositions

[0002] Cross-Reference to Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 673,438, titled “Control of Polymerization Kinetics by Formulation of Reaction Compositions,” filed July 19, 2024. and U.S. Provisional Patent Application No. 63 / 727,350, titled “Control of Polymerization Rate by Formulation of Reaction Compositions,” filed December 3, 2024. the entire contents of each of which are incorporated by reference herein.

[0004] Field

[0005] The disclosure relates to methods for controlling polymerization rate in relation to the formation of surface polymers on a substrate. In particular, the disclosure relates to the formulation of reaction compositions so as to provide a controlled rate of surface polymerization. Systems for carrying out the methods are also described.

[0006] Background

[0007] Forming polymeric structures on surfaces have become increasingly important in many technologies and applications. “Surface polymers”, “surface bound polymers” or “polymers on a surface” all describe a polymeric structure having polymer chains that are chemically bonded to a surface at one end through covalently bound polymerization initiators. Two methods, known by persons skilled in the art, can be used to achieve such polymeric structure, namely the “grafting to”-approach and the “grafting from”-approach (see Fig. 1 and Fig. 2). In the “grafting to”- approach (Fig. 1), polymers are pre-prepared in solution and then deposited onto the surface in question, since the pre-prepared polymers are designed in such a way that one of the chain-ends has some affinity for the surface of interest. Upon contact with the surface of interest, the polymers will self-assemble on said surface forming surface bound polymers. In the “grafting from”- approach (Fig. 2), small molecules capable of acting as polymerization initiators are covalently bound to the surface of interest in a pre-polymerization step. Subsequently polymerization is initiated via the polymerization initiators bonded on the surface. Accordingly, surface polymers are formed from the surface monomer-by-monomer.

[0008] While the “grafting to” approach allows for simple preparation procedures and detailed characterization, in that one can prepare the polymers using conventional polymerization methods that can maintain the bonding-to-surface property at the one end of the pre-formed polymer, before initiating the self-assembly procedure, the "‘grafting to”-approach lacks the ability to form high density surface bound polymeric structures nor flexibility in polymer structures, composition, etc.. Main equilibrium conformation of long polymeric structures in solution is a contracted, or a coiled polymer chain, unless the polymer solution is extremely diluted with highly solvating solvent or other means employed to stabilize extended conformation (e g., pH for ionic polymers). Such extra means to stabilize extended polymer chain conformation may complicate and interfere with the “grafting to” process conditions and make the approach less practical. Therefore, the self-assembly process is being halted by the steric repulsion between the coils of pre-made polymer chains as they self-assemble on the surface leading to loosely packed polymer coils on the surface (see Fig. 1). The “grafting fronT-approach allows for the formation of highly dense surface bound polymer structures, as the small initiating molecules can form a much more densely packed layer on the surface (compared to large polymer molecules, see Fig. 2). Such a densely packed layer of initiating molecules is guiding monomer molecule-by-monomer molecule formation of polymer chains, where the extended conformation of growing polymer chains is sterically stabilized by their close proximity to each other. As such, the surface bound polymer structure formed by a “grafting from” approach results in a much higher density of polymer chains. Additionally, as the “grafting from”-approach allows for highly dense surface bound polymer structures, a brush-like structure can be achieved, thus, the name “polymer brush”. In these structures, the polymers are stretched and forced to stand upright due to the steric repulsion between neighbouring polymers creating a unique structure known by people skilled in the art as a “polymer brush” structure. On surfaces, these structures are tethered / attached, usually covalently, at one end to the surface, typically to a solid or semisolid surface, thereby differing from polymers formed in solution and subsequently deposited onto a surface.

[0009] As mentioned above, surface polymers are prepared by one of the following two main strategies: “grafting to” or “grafting from”. In the “grafting to”-approach, polymer chains are deposited onto the surface in question. The “grafting to"-approach suffers from several drawbacks and limitations making it difficult to produce thick and dense surface polymers. In the “grafting fronf’-approach, the surface polymer growth (surface polymer chain propagation, extension of the chain by monomer units) is initiated from initiator-functionalized surfaces, using, for example, a controlled / ”living” polymerization technique, such as anionic polymerization, cationic polymerization. ring-opening polymerization, and controlled radical polymerization. Surface polymers within the present context are, thus, polymeric structures having polymer chains that are chemically bonded to a surface at one end via polymerization initiators. Such polymers may be tailored to provide specific chemical and / or physical properties and may produce precisely tailored chemical structures on a molecular scale. They may be used, for example, for storing certain chemical species, controlling transport properties, improving surface stability and properties, creating an interface in which dissimilar materials can bind or interact, and other functions. Surface polymers may subsequently join otherwise incompatible materials such as metals and plastics and improve adhesion between such otherwise incompatible materials (see, e.g., WO 2014 / 075695 Al).

[0010] Different polymerization techniques have facilitated the specific design and synthesis of surface polymers with strict molecular control and desired properties. In particular, the surface polymers can be viewed as nanoscale “building blocks” with a wide range of uses, vary ing from redox activity to biocompatibility and surface alteration, and due to the flexibility of the surface polymers, highly tailored thin films of surface polymers can be created with respect to chemical composition, thickness, density and architecture.

[0011] Surface polymers formed may form complex structures depending on monomeric building blocks used for the polymerization. Still, methods providing improved rate control of the polymerization on surfaces are desired as this contributes to reproducible formation of surface polymers with specific conformation and average dry film thicknesses.

[0012] Summary

[0013] In an aspect, the present disclosure relates to a method of controlling the rate of the formation of surface polymers on a substrate is provided comprising applying to the substrate a reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types the first solvent, and the second solvent are selected to control the rate of surface polymer formation. In an aspect of the present disclosure, a method of controlling the rate of formation of surface polymers on a substrate is provided comprising applying to the substrate a reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of two or more of: the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation. In the method, the relative amount of the first solvent to the amount of the second solvent may be selected to control the rate of surface polymer formation. In the method, the type of the first solvent, and the relative amount of the first solvent to the amount of the second solvent may be selected to control the rate of surface polymer formation. In the method, the ty pe of monomer may be selected to control the rate of surface polymer formation. In the method, the relative amount of the monomer to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the type of the monomer and the relative amount of the monomer to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the ty pe of catalyst / ligand complex may be selected to control the rate of surface polymer formation. In the method, the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the type of the catalyst / ligand, and the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the type of the catalyst / ligand complex are selected to control the rate of surface polymer formation. In the method, the relative amount of the monomer to the balance of the amount of the reaction composition, and the type of the catalyst / ligand complex may be selected to control the rate of surface polymer formation. In the method, the type of the monomer, and the relative amount of the catalyst / ligand to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the relative amount of the monomer to the balance of the amount of the reaction composition, and the relative amount of the catalyst / ligand to the balance of the amount of the reaction composition may be selected to control the rate of surface polymer formation. In the method, the rate of surface polymer formation may be selected to be linear so as to have a coefficient of determination, R2, during a selected time interval of polymerization above or equal to 0.95. In the method, the rate of surface polymer formation may be selected to be non-linear, so as to have a coefficient of determination, R2. during a selected time interval of polymerization below 0.95. The surface polymer growth process may be considered a multi-stage processes such that the rate of surface polymer formation may be selected to be linear in a first time interval and approaching and reaching a plateau in a second time interval. In the method, the surface polymerization may be stopped during the second time interval.

[0014] In the method, the first solvent may be present in an amount of 20 Vol% to 80 Vol%. calculated according to formula (I), wherein Vol umeFirst solvent is the volume of the first solvent, and wherein VolumeTotai is the volume of the first solvent, the second solvent, the monomer, the catalyst / ligand complex including any solvent, and the catalyst activator including any solvent. In the method, the ligand is selected from N,N, N’. A'". / V"’-pentamethyldiethylene-tnamine (PMDETA), tris[2- (dimethylamino)ethyl] amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridyl- methyl)amine (TPMA), 1,1, 4, 7, 10, 10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1, 4,8,11 -tetramethyl- 1,4, 8,11-tetraazacyclotetradecane (Me4Cyclam), and / or 2, T -bipyridyl (BiPy). In the method, the catalyst / ligand complex may be a complex selected from: Cu / PMDETA. Cu / MeeTREN, Cu / TREN. Cu / TPMA, Cu / HMTETA, Cu / TMEDA, Cu / MeiCyclam, and Cu / BiPy. In the method, the catalyst activator may be selected from sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose with GOx, and / or pyrogallic acid. The first solvent may have a dielectric constant, k, in the range of 5 to 80. The first solvent may be selected from methanol, ethanol, and isopropanol. The second solvent may be water. In the method, the solvent may further comprise a third solvent selected from aprotic solvents. The third solvent may be one or more of acetone, acetonitrile and dimethylsulfoxide (DMSO). The monomer may be selected from methyl methacrylate (MMA), 2-hydroxyethylmelhacrylale (HEMA), tert- butylmetacrylate (tBMA), acrylic acid (AA), methacrylic acid (MAA), styrene, and glycidyl methacrylate (GMA). The method may enable formation of surface polymers having an average dry film thickness of no more than 50 nm. The surface polymer may be formed within 30 seconds to 30 minutes. The method may enable formation of surface polymers having an average dry film thickness of no more than 25 nm. The surface polymer may be formed within 30 seconds to 30 minutes. The method may enable formation of surface polymers having an average dry film thickness of no more than 10 nm. The surface polymer may be formed within 30 seconds to 30 minutes. The method may enable formation of surface polymers having an average dry film thickness of no more than 5 nm. The surface polymer may be formed within 30 second to 30 minutes.

[0015] In an aspect of the present invention, a reaction composition is provided comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing a surface polymer dry film thickness of at most 50 nm.

[0016] In an aspect of the present disclosure, a reaction composition is provided comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing a surface polymer dry film thickness of at most 25 nm.

[0017] In an aspect of the present disclosure, a reaction composition is provided comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or t pes providing a surface polymer dry film thickness of at most 10 nm.

[0018] In an aspect of the present disclosure, a reaction composition is provided comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing a surface polymer dry film thickness of at most 5 nm.

[0019] In an aspect of the present disclosure, a polymer is provided, which polymer may be formed on a surface of a substrate by the methods described herein, wherein the applied relative amounts and / or types of two or more of the first solvent, the second solvent, monomer, the catalyst and ligand forming a catalyst / ligand complex, and the catalyst activator may be selected to control the rate of surface polymer formation.

[0020] In an aspect, a system for forming surface polymers on a substrate is disclosed, the system comprising a reaction composition container containing a reaction composition, said reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of the first solvent and the second solvent are selected to control the rate of surface polymer formation, and a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers of a specified average dry' film thickness to be formed on the portion of the polymerization initiator-modified substrate. The system may be such comprising a reaction composition container containing a reaction composition, said reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts to the balance of the amount of the reaction composition and / or types of two or more of the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation, and a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers of a specified average dry film thickness to be formed on the portion of the polymerization initiator- modified substrate. The substrate displacement device may comprise any one of a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism. The system may further comprise a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is configured to bring the at least a portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition. The system may further comprise one or more cleaning containers, the cleaning containers containing cleaning agents, wherein the substrate displacement device is configured to bring the at least a portion of the polymerization initiator-modified substrate into contact with the cleaning agents of the one or more cleaning containers prior to, or subsequent to, bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition, and / or the substrate displacement device is configured to bring the at least a portion of substrate into contact with the cleaning agents in the one or more cleaning agents prior to. or subsequent to. bringing the at least a portion of the substrate into contact with the polymerization initiator. The system may comprise a container for pre-wetting the at least a portion of the substrate prior to bringing the at least a portion of the substrate into contact with the reaction composition. The system may comprise a reaction composition management system. The reaction composition management system comprises one or more sensors in relation to the reaction composition container. The sensors may be configured to measure the pH of the reaction composition or the molecular oxygen concentration in the reaction composition. The system may comprise one or more flow control devices. The flow control devices may be selected from circulation pumps, flow guidance grids, filters, and / or mechanical stirring means. The system may compnse a heating device for annealing the substrate prior to, or subsequent to, bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition.

[0021] Brief Description of the Drawings

[0022] Certain embodiments of the matter disclosed herein are illustrated in the accompanying drawings. The drawings are, however, in no way intended to limit the scope of the disclosure. In the drawings:

[0023] Fig. 1 illustrates the ’‘grafting to’’ concept schematically.

[0024] Fig. 2 illustrates the '‘grafting from” concept schematically.

[0025] Fig. 3 illustrates linear polymerization rate for 3 different surface polymer formations.

[0026] Fig. 4 illustrates non-linear polymerization rate for 3 different surface polymer formations. Fig. 5 illustrates linear polymerization rate with coefficient of determination. R2. indicated.

[0027] Fig. 6 illustrates non-linear polymerization rate with coefficient of determination, R2, indicated. Fig. 7 shows an initial rapid surface polymerization phase (“A”) followed by a plateau phase with low further surface polymerization (“B”). Fig. 8 is a schematic illustration of a system for forming surface polymers on at least a portion of a substrate, according to embodiments of the present invention.

[0028] Fig. 9 is a schematic illustration of an exemplary substrate displacement device, the substrate displacement device comprising a roll-to-roll processing device, in accordance with an embodiment.

[0029] Fig. 10 shows a plot of the average dry film thickness of a surface polymer as a function of polymerization time for 5 different solvent composition ratios of DI water and ethanol (Reaction IDs 5. 1-5.3, 5.4, 5.5-5.6, 5.7 and 5.8), see Example 5.

[0030] Fig. 11 shows the average dry' film thickness of a surface polymer as a function of polymerization time for three different catalyst T concentrations, see Example 6.

[0031] Fig. 12 shows the results obtained in Example 7. The average dry film thickness as a function of polymerization time for reaction compositions comprising Dl-water and one of methanol, ethanol, and isopropanol is shown.

[0032] Fig. 13 shows the average dry' film thickness after 20 minutes polymerization time for Reaction ID 7.1, 7.2, and 7.3, see Example 7, plotted against the dielectric constant of the first solvent.

[0033] Fig. 14 shows a plot of the average dry film thickness as a function of polymerization time for 3 different reaction compositions comprising different ratios of Dl-water and isopropanol see Example 8.

[0034] Fig. 15 shows a plot of the average dry’ film thickness as a function of polymerization time for the reaction conditions in Example 9.

[0035] Fig. 16 show s a plot of the average dry' film thickness as a function of polymerization time, for the reaction compositions of Example 10.

[0036] Fig. 17 shows the average dry film thickness as a function of polymerization time for the surface polymerizations of Example 11.

[0037] Fig. 18 shows the average dty film thickness of the surface polymerizations of Example 12 as a function of polymerization time for different solvent compositions.

[0038] Fig. 19 shows the average dry film thickness of formed surface polymers as a function of volume ethanol (EtOH). see Example 12.

[0039] Fig. 20 shows the average dry' film thickness as a function of polymerization time, see Example 13.

[0040] Fig. 21 shows the polymerization rates of ligands MeeTREN, TPMA and PMDETA, respectively, and surface polymerization thicknesses of PMMA in a polymerization rate experiment where only the type of ligand is varied in the reaction composition, see Example 15.

[0041] Fig. 22 shows the polymerization rates of ligands MeeTREN, TPMA and PMDETA, respectively, and surface polymerization thicknesses of PGMA in a polymerization rate experiment where only the type of ligand is varied in the reaction composition, see Example 16.

[0042] Fig. 23 shows polymerization rates of styrene monomer in reaction compositions containing first solvent with different dielectric constants, see Example 17.

[0043] Fig. 24 shows the average dry film thickness as a function of polymerization time for surface polymerization of styrene monomer, see Example 18.

[0044] Detailed Description

[0045] Disclosed herein is a method of controlling the formation of surface polymers based on the recognition that certain formulations of the reaction composition for forming the surface polymer film on a substrate unexpectedly influence the rate of the surface polymer formation, and, thus, the average dry film thickness of the obtained surface polymers.

[0046] In an aspect, the present disclosure relates to a method of controlling the rate of the formation of surface polymers on a substrate comprising applying to the substrate a reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types the first solvent, and the second solvent are selected to control the rate of surface polymer formation.

[0047] In an aspect, the present disclosure relates to a method of controlling the rate of the formation of surface polymers on a substrate comprising applying to the substrate a reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of two or more of: the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation. The method may be such, wherein the relative amount of the first solvent to the amount of the second solvent is selected to control the rate of surface polymer formation.

[0048] The method may be such, wherein the type of the first solvent, and the relative amount of the first solvent to the amount of the second solvent are selected to control the rate of surface polymer formation.

[0049] With the expression “rate of surface polymer formation”, “polymerization rate” or simply “rate” is meant that within a given timeframe, surface polymerization (propagation of polymer chains from polymerization initiator sites on the surface) occurs as a function of time to an extent where a certain average dry film thickness on a surface is obtained. The relationship between average dry film thickness and polymerization time, during a polymerization time interval, may be overall linear as exemplified by Fig. 3. The relationship between the polymer average dry film thickness and polymerization time, during a polymerization time interval, may be overall non-linear as exemplified by Fig. 4. In Fig. 3, the surface polymer formation is highly linear throughout the polymerization time interval and does not, as in the Fig. 4, approach a polymerization plateau during the polymerization time interval, at which the surface polymer chain ends propagate slowly or have partially terminated. In Fig. 4. a first polymerization time interval is linear, and a second polymerization time interval is linear but with a slower polymerization rate, thus, given the overall non-linear polymerization rate during the total polymerization time. The polymerization rates versus the polymerization time as shown in Fig. 3 and Fig. 4 may also be referred to as “polymerization rate profile”.

[0050] Controlling the rates of both surface polymer propagation and surface polymer chain-end termination may allow for a high degree of predictability and control of the average dry film thicknesses of formed surface polymers. Thus, being able to control polymerization rate to follow a path as shown in Fig. 4 makes possible specific design of surface polymer forming methods that, after a certain polymerization time, will result in essentially the targeted and desired average dry film thicknesses.

[0051] The inventors have recognized that by selecting a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, the rate of the surface polymer formation may be controlled so as to modulate the polymerization rate profile.

[0052] A surface polymer formation following a linear rate (path) during a polymerization time may further be illustrated as shown in Fig. 5. Here, the surface polymerization displaying linear relationships between the average dry film thickness (y-axis) and polymerization time (x-axis - polymerization time after activation of catalyst / ligand complex) is shown. In Fig. 5, it is assumed that a certain number of substrates are subjected to surface polymerization after activation of the catalyst / ligand complex, and at certain times, at least one substrate is withdrawn, and the average dry film thickness measured (in Fig. 5, at time 2 minutes, 5 minutes, 7.5 minutes, 10 minutes, 20 minutes, and 40 minutes). The polymerization rate is here defined to be linear within the context of this disclosure, if the average dry film thickness as a function of polymerization time after activation of catalyst / ligand complex can be fitted to a linear regression with a coefficient of determination (R-squared or R2) between 1 and 0.95 (1 > R2> 0.95) during a selected time interval (here time 0 minutes to 40 minutes). R2is always between 1 and 0. The higher the value, the higher the percentage of points that fall within the linear regression. Hence, R2provides a measure of the “goodness-of-fif ’. R2> 0.95 signifies that > 95% of the average dry film thicknesses fall within the linear regression.

[0053] A surface polymerization following a nondinear rate (path) during a certain time interval between the average dry film thickness (y-axis) and polymerization time after activation of catalyst / ligand complex (x-axis) may further be illustrated as shown in Fig. 6 (as in the case of Fig. 5, at least one substrate is withdrawn and analyzed at time 2 minutes, 5 minutes, 7.5 minutes, 10 minutes, 20 minutes, and 40 minutes). If the average dry film thickness as a function of the polymerization time is fitted to a linear regression, and the R2value is < 0.95 within a certain time interval (here approximately time 0 minutes to time approximately 40 minutes), it is in this context defined to be non-linear. In Fig. 6, the non-linear polymerization rate is due to a convergence of the data points for polymerization times above 10 minutes. This convergence is giving a plateauing trend (i.e. approaching a polymerization plateau) in the polymerization rate profile, recognized by average dry film thickness values of similar magnitude at two adjacent time points (e g., similar average dry film thickness at minutes 20 and minutes 40). In many cases, approaching a polymerization plateau will be sufficient to control the formation of surface polymers to a desired average dry film thickness. Fig. 7 illustrates the plateau of surface polymer formation showing an initial linear surface polymer propagation phase (“A”), followed by a surface polymer propagation phase (“B”) approaching and reaching a polymerization plateau. Within the present context, the terms ‘'plateau” and '‘polymerization plateau” may be used interchangeably. It should be mentioned that during surface polymer propagation phases “A” and “B” individually, R2may be > 0.95, whereas for the whole surface polymerization time interval (“A” and “B”), R2may be < 0.95. Since both phases “A” and “B” in Fig. 7 may have R2> 0.95, another parameter may be applied to determine whether the polymerization plateau “B” has been reached. The ratio between the determined lowest average dry film thickness, T IN. and the highest determined average dry film thickness, TMAX, during a certain time interval may be used to evaluate if the polymerization plateau has been reached. By way of example and for illustrative purposes, the average dry film thickness following two consecutive polymerization times, e.g., a polymerization time of 20 minutes (T IN) and 40 minutes (TMAX) may be used to evaluate if the polymerization plateau has been reached after 20 minutes. If the ratio TMIN / TMAX is > 0.8, the polymerization plateau is considered reached. When estimating the ratio between TMIN and TMAX, standard deviations on the measured average dry’ film thicknesses should be taken into consideration, giving rise to variations in the measured average dry’ film thicknesses. The ratio TMIN / TMAX will in general approach 1 when the polymerization plateau is reached. As described herein, the average dry film thickness may be measured in a variety of manners.

[0054] The inventors have recognized that the coefficient of determination, R2, for a linear regression of the surface polymer dry film thickness as a function of the polymerization time, together with the non-linear convergence of the average dry’ film thickness to a plateau are valuable tools and may be used in modulating the rate of surface polymer formation. The inventors have found that the linearity of the rate profile of the surface polymerization (polymerization rate profile) may be modulated and controlled to provide a surface polymer propagation approaching and reaching a polymerization plateau, and at the same time the average dry film thickness of formed surface polymer may be modulated so as to result in “thicker” or “thinner” surface polymers (referring to the average dry film thickness of the formed surface polymer). The inventors have found that the rate of the surface polymerization may be modulated and controlled to provide a surface polymer propagating in a linear fashion with polymerization time, where the rate of formation of the surface polymer may be modulated so as to proceed slower or faster, i.e., the slope of the average dry’ film thickness versus polymerization time may be controlled through the reaction composition, e g., solvent composition, monomer amount (concentration), catalyst / ligand complex type and amount (concentration). As disclosed herein, the several components of the reaction composition applied in the surface polymer formation may be chosen so as to provide the desired polymerization rate control.

[0055] In accordance with the disclosure herein, methods of controlling surface polymer formation are provided. The relative amount of the first solvent to the amount of the second solvent may be selected to modulate and / or control the rate of surface polymer formation. The t pe of the first solvent, and the relative amount of the first solvent to the amount of the second solvent may be selected to modulate and / or control the rate of surface polymer formation. The relative amount and / or the type of the first solvent and the second solvent may be selected together with the following to modulate and / or control the rate of formation of the surface polymers: The type of monomer may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the monomer to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The t pe of the monomer and the relative amount of the monomer to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The type of catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The type of the catalyst / ligand complex, and the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The ty pe of the monomer, and the type of the catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The balance of the amount of the reaction composition, and the type of the catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The type of the monomer, and the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the monomer to the balance of the amount of the reaction composition, and the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The ty pe of the catalyst activator may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst activator to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The type of the monomer, and the type of the catalyst activator may be selected to modulate and / or control the rate of surface polymer formation. The type of the monomer, and the relative amount of the catalyst activator to the balance of the reaction composition may be selected to modulate and / or control the rate of the surface polymer formation. The type of catalyst activator, and the type of catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst activator to the balance of the reaction composition, and the type of catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The type of the catalyst activator, and relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation. The type of the catalyst activator, type of the monomer, and the type of the catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst activator to the balance of the reaction composition, type of the monomer, and the ty pe of the catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst activator to the balance of the reaction composition, the relative amount of the monomer to the balance of the reaction composition, and the type of the catalyst / ligand complex may be selected to modulate and / or control the rate of surface polymer formation. The relative amount of the catalyst activator to the balance of the reaction composition, the relative amount of the monomer to the balance of the reaction composition, and the relative amount of the catalyst / ligand complex to the balance of the reaction composition may be selected to modulate and / or control the rate of surface polymer formation.

[0056] In the "grafting fronr-approach. surface polymers propagate from polymerization initiators attached to the surface or a portion or portions of a surface of a substrate. Attachment of polymerization initiators are described below. The “monomer-by-monomer” (“grafting from”) approach for formation of surface polymers offers myriads of monomer ty pes and combinations thereof in forming surface polymers of desired structure, composition, and properties. The methods presented herein have proven sufficiently oxygen insensitive to make possible the polymerization to generally take place under ambient atmospheric conditions, and this offers a flexibility in the design of surface polymers as well as in the preparation of them, including high- volume manufacturing. Such flexibility in structure, composition, and properties is difficult to achieve with the grafting to approach. Atachment of polymerization initiators to a surface of a substrate, from which surface polymers may be propagated, may be performed by various procedures. Polymerization initiators are covalently bonded to the surface of the material, see, e.g., WO 2014 / 0075695. The polymerization initiators may be provided with a predefined surface chemistry to enable atachment onto the surface of the substrate, depending on the nature of the substrate. Non-limiting examples of suitable chemistries for ataching polymerization initiators on surfaces include but are not limited to: aryl diazonium salts, organosilanes, organothiols, organophosphonic acids, organophos- phonates, catechols, iodonium salts, alkenes, alkynes, and sol-gel coatings. Surface anchored polymerization initiators can be prepared as multilayer films or monolayer films. Monolayer films can be densely packed (full monolayer coverage) or partly packed, covering all or only a part of the available surface. The density of the polymerization initiator influences the density and may possibly influence the growth rate of the subsequently formed surface polymer. Density of initiators would be understood by persons of ordinary skill as the number of polymerization initiators per unit area of the substrate.

[0057] The atachment of polymerization initiators usually follows a 1-step or a 2-step process. The 1- step process applies grafting of benzyd halide (like benzyl chloride) or secondary or tertiary' halide moieties onto the surface of the substrate either by diazonium or silane grafting. The benzyl halide and secondary and tertiary halide moiety act as the polymerization initiator for the following surface-initiated polymerization. The 2-step process usually applies surface grafting of an initial organic compound with a nucleophilic group, and in a second step using the nucleophilic group to atach an initiator moiety. The nucleophilic group may include a hydroxyl or amine group. Then, the nucleophilic group may be reacted with an electrophile to add an initiator moiety, forming a covalent bond between the two. The initiator moiety may be, e.g., benzyl halide and tertiary halide moieties.

[0058] The atachment process is further described below. The procedures may in general apply to all types of substrates. Prior to atachment of polymerization initiators to form the polymerization initiator layer, the surface of the substrate may be cleaned using various techniques, including sonication in ammonia, ABC-clean A200, a solution of DI-water:NHs:H2O2 (5: 1: 1), acetone, and / or water. Following atachment of polymerization initiators, the substrate may be annealed at ambient conditions or at elevated temperatures. Silane grafting 1-step:

[0059] Initiators can be attached to a surface in one step by silane grafting of trialkoxy silane with benzyl halide or tertiary halide groups. The silane grafting is normally done by vapor deposition, in solution, by spray coating, or paint-on coating.

[0060] Diazonium grafting 1-step:

[0061] Initiators can be attached to a surface in one step by grafting aryl diazonium salts with benzyl halide groups. The diazonium grafting is normally done either by activating the aryl diazonium salt electrochemically or chemically or by letting it react spontaneously. Diazonium salts can be pre-synthesized before being used for grafting reaction or formed in-situ during grafting reaction from a set of precursors added to the grafting reaction solution.

[0062] Diazonium grafting 2-step:

[0063] Another route of initiator attachment is by a two-step process. The first step being grafting of an aryl diazonium salt that contains a nucleophilic group (alcohol or amine). In a second step a nucleophilic acyl substitution reaction adds a halogen containing group, giving the attached polymerization initiator.

[0064] Silane grafting 2-step:

[0065] The first step being grafting of a silane that contains a nucleophilic group (alcohol or amine). In a second step, a nucleophilic acyl substitution reaction adds a halogen containing group, giving the attached polymerization initiator.

[0066] Other processes for forming the polymerization initiator layer may be applied. An example is the polymerization initiator p-(chloromethyl)phenyltrimethoxysilane (CPTMS) which may be attached using a vapor deposition method or a dipping method. Another example is the polymerization initiator j»-(chloromethyl)phenyltrimethoxysilane (CPTMS) in combination with the "‘dummy’7initiator (3-glycidyloxypropyl)tnmethoxysilane (GPTMS). the latter which display an epoxy (epoxide) group suited for further modification by ring-opening of the epoxy (epoxide) group. Within the present context, the term “dummy initiator”, “non-polymerization initiator” or “initiator not initiating polymerization” is a chemical entity which does not initiate surface polymer formation. The presence of polymerization initiators in the polymerization initiator layer may be “diluted” by the simultaneous presence of “dummy” initiators to form a polymerization initiator layer containing polymerization initiators active for surface polymer formation and chemical entities (the “dummy” initiator) not active for surface polymer formation. The “dummy” initiator may be added in a certain percentage together with the polymerization initiator, thus, competing with the polymerization initiator about available attachment sites on the substrate surface. Dilution of the polymerization initiator with a “dummy” initiator may be used to adjust the density of the polymerization initiators on the surface of the substrate, thus, aiding in controlling density (“grafting density ”, i.e. the number of surface polymer chains per unit area of the substrate) of subsequently formed surface polymers. Here “grafting” means monomer-by -monomer propagation of surface polymers from the polymerization initiators. The density of the initiators (both polymerization initiators and non-polymerization / ”dummy” initiators) influences the density of the subsequently formed surface polymer propagated from the polymerization initiators. As mentioned above, the density of polymerization initiators is intended to mean the number of polymerization initiators per unit area. Non-limiting examples of suitable percentage ratios (molecular-% (mol%) of polymerization initiator to non-polymerization initiator) may be in the range 100:0 (no non-polymerization initiator), 90: 10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 10:90.

[0067] For forming surface polymers as described herein, suited polymerization initiators may be CPTMS, BiBB, or chloromethyl (CM) moieties.

[0068] It is expected that a wide range of different substrates will be useful in connection with the disclosure herein, however, suited substrates should provide a surface, allowing firstly attachment of first polymerization initiators, and secondly formation of surface polymers of first polymer molecules from said first polymerization initiator sites. Substrates may wholly or partly be composed of metal (like aluminum, steel, nickel, gold, silver, platinum, chrome, copper, iron and alloys), glass, carbon, graphite, graphene, carbon black, monoclays, ceramics, composite materials, plastics, polymer materials, semiconductors, compound semiconductors (e g., gallium arsenide (GaAs), gallium nitride (GaN), germanium sulfide (GeS), and indium phosphide (InP)), and particles (e.g., Si, metal, metal alloys and coated particles). Substrates may be patterned or unpattemed. If patterned, substrate surface(s) may comprise one or more of the mentioned substrate materials. The substrate may be composed of several layers of different materials, optionally being attached together, e.g., using a glue, or be a blend of different materials. The substrate may have any size, shape and structure, including an elongated structure, and may be in the form of pieces, threads, fibers, cables, wires, hollow structures, particles, nanoparticles, monolayers etc. Particles and nanoparticles may be uncoated or coated with another material and may further be in the form of aggregates (multiple (nano)particles forming an assembly of individual (nano)particles). Aggregates may in some cases be viewed as one (nano)particle. Substrates may also be composed of one or more of the above mentioned, e g., the substrate may be a base material comprising glass, silicon, GaAs, GaN, GeS, InP, dielectric material, ceramic, composite, as well as layered and patterned structures thereof. Substrates may have any form and shape, be elongated, be hollow, have protrusions or recesses, etc.

[0069] A portion or portions of a substrate may be “masked” so as to only attach polymerization initiators to unmasked areas on the substrate. Different techniques may be used to accomplish such specific attachment of polymerization initiators. For example, the portion or portions of the substrate maybe covered by a film or layer during polymerization initiator attachment. Alternatively, contact between a portion or portions of a substrate and the reaction composition for forming surface polymer may be limited by, e.g., a masking with for example a film or a layer covering the portion or portions of the substrate on which surface polymers are not to be formed, or by immersing, into the reaction composition, only those portions of the substrate onto which surface polymers are to be formed. In general, any masking should be non-reactive with other chemistries to which the substrate is exposed and should be easily removable from the substrate.

[0070] Different polymerization techniques have facilitated the specific design and synthesis of surface polymers with strict molecular control and desired properties. In particular, the surface polymers can be viewed as nanoscale “building blocks” with a wide range of uses, varying from redox activity to biocompatibility and surface alteration, and due to the flexibility of the surface polymers, highly tailored thin films of surface polymers can be created with respect to chemical composition, thickness, density and architecture.

[0071] Several methods for forming surface polymers are known, among them SI-ATRP (surface-initiated atom transfer radical polymerization), SI-RAFT (surface-initiated reversible-addition fragmentation chain transfer). SI-NMP (surface-initiated nitroxide-mediated polymerization), SI- PIMP (surface-initiated photoiniferter-mediated polymerization), and SI-A(R)GET (surface- initiated activators (regenerated) by electron transfer) ATRP. A review is given in Chem. Rev. 2009, 109, 5437-5527. Other approaches include SET-LRP (single-electron transfer living radical polymerization) and SARA ATRP (supplemental activator and reducing agent atom transfer radical polymerization).

[0072] When forming surface polymers, polymerization initiators are firstly formed on the surface or portion(s) of the surface onto which the surface polymers are to be formed. Secondly, the surface or portion(s) of the surface is brought into contact with suitable monomers, catalysts, ligands and optionally a solvent, or suitable monomers, catalyst, ligands, a reducing agent and optionally a solvent, whereby the surface polymer can form using certain reaction conditions. The polymerization initiators and the monomers are chosen so as to suit the purposes and properties of the resulting surface polymers. Surface polymers may also be formed as layers of surface polymers by repeating the polymeric architecture, e.g., using another starting monomer (so-called block copolymers).

[0073] Among these known procedures for formation of surface polymers, (ARGET) ATRP and SET- LRP are widely used. For the polymerizing chains to propagate, a monomer, a catalyst, a ligand and a solvent are needed. In (ARGET) ATRP and SET-LRP polymerizations, some reactions activate the catalyst, thereby, promoting polymerization, and at the same time, other reactions deactivate the catalyst to impede polymerization. SARA-ATRP and SET-LRP are described, e.g., in https: / / www.cmu.edu / maty / atrp-how / procedures-for-initiation-of-ATRP / SARA-ATRP-or- SET-LRP.html.

[0074] Both the SET-LRP and (ARGET) ATRP method rely on the formation of a complex between the ligand and a halide formed with a transition metal as specified in the Periodic Table (usually CuCh or CuBr2 in the case of ARGET ATRP, and Cu(0) in the case of SET-LRP, but other transition metals and halogens may be used).

[0075] The ARGET ATRP involves a halogen transfer between a dormant halogen capped species, Pn-X and Cu(I)X / L catalyst, resulting in the formation of a propagating radical (Pnradical) and Cu(II)X2. The propagating radical undergoes polymerization with monomers, forming the growing polymer chain. Controlling the ratio between Cu(I)X / L and Cu(II)X2 / L allows control of the polymerization itself.

[0076] From WO 2019 / 196999 Al, which is incorporated by reference in its entirety, as if fully set forth herein, an alternative oxygen-tolerant method for forming surface polymers is disclosed. The catalyst / ligand complex described in WO 2019 / 196999 Al is halogen free in so far as the catalyst / ligand complex formed is not complexed with a halogen anion. An advantage is that the complex formed between the transition metal and the ligand is inactive (i.e., not available for initiating polymerization of the monomer) and stable (oxygen-insensitive), but the system can be activated “on demand’', thus, initiating polymerization and propagation of the surface polymers.

[0077] In accordance with the methods disclosed herein, the substrate including one or more surfaces of the substrate, or portions of one or more surfaces of the substrate may be brought into contact with the reaction composition for surface polymer formation. It is understood that the surfaces or portions of the surfaces of the substrate may have been subjected to attachment of polymerization initiators prior to contact with the reaction composition. It is to be understood that the components of the reaction composition may be mixed and subsequently be brought into contact with the substrate. In another embodiment, the components of the reaction composition may be prepared as discrete compositions and mixed prior to or following contact with the substrate. E.g., the monomer may be prepared as a discrete component (solvated in the solvent if needed), and the catalyst / ligand complex may be brought into contact with the catalyst activator, whereafter the activated catalyst / ligand complex may be brought into contact with the substrate, followed by addition of the monomer. E.g., the monomer, the catalyst / ligand complex, and the solvent may be brought into contact with the substrate, and the catalyst activator may be dissolved in the solvent and subsequently be added. E.g., the monomer, the catalyst / complex, the solvent, and the catalyst activator may be pre-mixed, and subsequently be brought into contact with the substrate.

[0078] For forming surface polymers, the substrate and the reaction composition as defined herein are typically kept in contact with each other for a suitable period (residence time or polymerization time), sufficiently to form surface polymers essentially having an average dry film thickness within a desired range. The polymerization time may be as long as needed. Suited polymerization times include, but is not limited to, up to 24 hours, e.g., 2 seconds, 5 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds. 1 minute, 5 minutes. 30 minutes, 1 hour, 2 hours. 3 hours, 4 hours and 5 hours. For a manufacturing perspective, polymerization times between 20 seconds and 20 minutes may be suitable. The surface polymer formation may take place at ambient temperature (room temperature), or with cooling or heating. Suitable temperatures include, but are not limited to, such from 5°C up to 120°C, such as from room temperature (approximately 20°C) to 120°C. Specific temperatures include, but are not limited to, 5°C, 10°C, 15°C, 20°C, room / ambient temperature (approximately 20°C), 30°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C. and 120°C. The polymerization time and temperature during the polymerization time may suitably be computer controlled. Following formation of surface polymers, the substrate may be subjected to optionally multiple rinsing and cleaning processes, typically involving flushing with a suitable solvent, sonicating, and / or drying at room temperature or elevated temperature ("annealing").

[0079] It is to be understood that by the term ‘’thickness of a surface polymer’ or “thickness of a polymer on a surface” is meant the film formed on the substrate, i.e., the surface polymer as defined herein. The thickness is often measured as the dry film thickness by ellipsometry but may be measured by other means such as reflectometry or by measuring a step edge in the coating by atomic force microscopy or profilometry. To determine the dry film thickness, several ellipsometry measurements are taken in evenly spaced positions on the substrate surface. At a beam incidence angle of 65° the beam spot of the ellipsometer, i.e., the area from which each measurement collects data for the thickness calculation, is approximately 0. 16 cm2. E.g., for a 2” silicon wafer quadrant substrate (total area of -20.3 cm2), different data collection routines may include 10. 45. or more measurement spots, meaning that the area from which thickness data is collected ranges from 1 .6 cm2to 7.2 cm2or more, corresponding to thickness data being obtained from 7.8 % to 35.5 % of the total surface area. Adding more measurement points to the measurement routine would mean that average dry film thickness data would be obtained from a larger fraction of the surface area, although the inventors generally find that the good homogeneity of the surface polymers presented herein may suffice for determining the average dry film thickness of a surface polymer. Generally speaking, a substrate with a surface polymer film may be considered dry when no visible solvent film, droplets, or residues are observed, by visual inspection, on the surface of the substrate. Measurements such as atomic force microscopy and profilometry demand that a step edge is made in the coating from the outer edge of the coating and all the way to the surface of the substrate, by e.g. scratching. In the dry state, the surface-tethered polymer molecules acquire a conformation between fully collapsed and stretched conformation where the degree of stretching depends on the grafting density. The reaction composition to be used in the disclosed methods comprises a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent. Suitable monomers, catalysts and ligands, and catalyst activators are indicated below.

[0080] Non-limiting examples of appropriate monomer types include anionic, cationic, zwitterionic, protic and aprotic monomers, and include acrylates, methacrylates, halogen-substituted alkenes, acry lamides, methacrylamides, and styrenes, as well as mixtures thereof. The generic monomer structure comprises a polymerizable part (such as a vinyl group), which in certain embodiments is connected to a functional group responsible for the specific functionality (e.g., adhesion, permeability, electric and ionic conductivities) of the certain monomer through a certain linker chemistry.

[0081] For acrylate monomers, non-limiting examples of functional moieties include but are not limited to: alkyl groups, aryl groups, sulfonates, fluorosulfonates, carboxyls, metal carboxylates, ethers, poly(ether) groups, bis(sulfonyl)amides, fluorinated sulfonates, perfluoroalkyl carboxylate, borate, fluorinated borate, borate ester derivatives, bis(trifluoromethane)sulfonimide, triflimides and derivatives thereof, halogenated alkyl chains, and mono-, di-, and tri-alkoxy silanes.

[0082] The polymerizable part and the functional part of the monomer can, in certain embodiments, be connected by a linker moiety. Non-limiting examples of appropriate linker chemistries include but are not limited to alkyl chains, esters, ethers, poly(ethers), amines, amides, aryls, and any combination(s) thereof. Non-limiting examples of appropriate acrylate monomers containing alkyl linkers include but are not limited to methyl acrylate, ethyl acrylate, hydroxy ethyl acrylate, and lauryl acry late. Non-limiting examples of monomers using ether and poly(ether) linker chemistry' include but are not limited to poly(ethylene glycol) methyl ether acrylate, and poly(ethylene glycol) acrylate. Non-limiting examples of monomers without linker chemistry include but are not limited to acrylic acid, lithium acrylate, sodium acry late, and vinyl imidazole.

[0083] For methacrylate monomers, non-limiting examples of appropriate functional moieties include but are not limited to: carboxylic acids, metal carboxylates, esters, alkyl alcohols, oxiranes, linear and branched alkyl groups, alkenes, ar l groups, sulfonates, fluorosulfonates, bis(sulfonyl)amides, fluorinated sulfonates, perfluoroalkyl carboxylate, borate, fluorinated borate, borate ester derivatives, bis(trifluoromethane)sulfonimide, triflimides, and derivatives thereof, halogenated alkyl chains, and mono, di, and tri-alkoxy silanes.

[0084] Non-limiting examples of linker chemistries include but are not limited to alkyl chains, esters, ethers, poly(ethers), amines, amides, aryls, and any combination(s) thereof.

[0085] Non-limiting examples of methacrylate monomers include but are not limited to methacrylic acid, lithium methacrylate, sodium methacry late, methyl methacrylate (MMA), potassium 3-sulfpropyl methacrylate (K-SPMA), 2 -hydroxyethylmethacrylate (HEMA). glvcidyl methacrylate (GMA), ethyl methacrylate, n-butyl methacrylate (BuMA), tert-butyl methacrylate (tBMA), lauryl methacrylate. (((perfluorobutyl)sulfonyl)oxy)methyl methacrylate, 3-(N-((trifluoromethyl)- sulfonyl)sulfamoyl)propyl methacrylate. lH,lH,2H,2H-heptadecafluorodecyl methacrylate (HFDMA). allyl methacrylate (AMA), 2-((triethoxysilyl)oxy)ethyl methacrylate, and 2-(3- (tnethoxysilyl)propyl)ethyl methacrylate.

[0086] Non-limiting examples of acry late monomers include but are not limited to methyl acry late (MA), tert-butyl acrylate (IBA), lauryl acrylate (LA), and 2-hydroxyethylacrylate (HEA).

[0087] Non-limiting examples of appropriate halogen-substituted alkene monomers include but are not limited to vinyl chloride, vinylidene difluoride, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene.

[0088] Non-limiting examples of appropriate acrylamide monomers include but are not limited to acrylamide, A-Ao-propylacrylamide, AAe / 7-butylacrylamide. and A-hydroxy ethyl acrylamide.

[0089] Non-limiting examples of appropriate methacrylamide monomers include but are not limited to N- Ao-propylmethacrylamide. methacrylamide. A-teA-butylmethacrylate, and A-hydroxy ethyl methacrylamide. Non-limiting examples of appropriate styrene monomers include but are not limited to sty rene, 4- methylstyrene, 2,3.4.5.6-pentafluorostyrene, / ?-divinylbenzene, 4-chlorostyrene, sodium 4-vinyl- benzenesulfonate, lithium 4-vinylbenzenesulfonate, and 4-vinylphenyl 1,1, 2,2,3, 3,4,4,4-nona- fluorobutane- 1 -sulfonate.

[0090] Monomer(s) may be chosen to provide compatibility / adhesion / elasticity / surface properties, as appropriate for a specific application. Monomer(s) may also be selected to enhance or diminish electrical and / or ionic conductivity, and / or permeability. Monomers may be chosen to improve interface stability of a surface in question. Furthermore, introduction of functional groups or combination of functional groups may provide improvement of various desired properties, like density, dielectric constants, diffusion barrier, wettability, etc. Monomers may suitably be used in an amount corresponding to a percentage of the total volume of the reaction composition (see formula (I)). For example, a liquid monomer may constitute e.g. 0.5 Vol%, 2 Vol%, or 10 Vol% of a reaction composition. In accordance with the present disclosure, an amount of monomer may be chosen to obtain desired surface polymerization rates, solubility of the monomer, and cost of the monomer. The monomer(s) may suitably be used in the range 0.5 Vol% to 50 Vol%.

[0091] Following formation of the surface polymer, the formed surface polymer is indicated with a “P” as prefix to the monomer. By way of example, methyl methacrylate monomer is denoted MMA, and after polymerization, the surface polymer is denoted PMMA. Likewise. 2-hydroxyethyl methacrylate is denoted HEMA, and after polymerization, the surface polymer is denoted PHEMA.

[0092] Catalysts to be used herein for forming surface polymers may be selected from several different metals, e.g., transition metals as given in the Periodic System. Examples of such transition metals are, e.g., copper (Cu), iron (Fe),and ruthenium (Ru. Specific examples of such catalysts include Cu2O, CuO, CuCl, CuCh, CuBr, CuBr2, FeCh and FeCh, RuCb, RuCh as well as combinations thereof. Some halogenide salts may be used as hydrates. The catalyst concentration in the reaction composition is typically in the range 0.001-1 mM. The concentration of catalyst in the reaction composition is preferrable in the range 0.02-0.32 mM, for example 0.02 mM, 0.04 mM, 0.08 mM, 0.16 mM, or 0.32 mM. The activator for the catalyst (e.g., an oxygen scavenger) may be used in excess compared to the catalyst. Excess catalyst activator may, e.g., be 10-500 times. The catalyst activator is responsible for the turnover between oxidized deactivating and / or activating catalyst states. It is presently believed that the principal reaction pathway for catalyst activation is reduction, that is. the catalyst activator is a species which is capable of reducing the catalyst of the complex between the catalyst and the ligand from its inactive state to its catalytically active state, where surface polymer formation can take place. Examples of suited catalyst activators are sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, tin 2- ethylhexanoate, sodium phenoxide, sodium dithionite, and a mixture of iron powder and sodium chloride.

[0093] Ligands to be used herein include, but are not limited to, nitrogen-containing ligands. Non-limiting examples of such nitrogen-containing compounds are bi-, tri-, or tetradentate amine ligands (containing two, three or four amine substituents) which are aliphatic and / or aromatic in nature. In particular, such ligands include N AC ' / N' -pentamethyldiethylene-triamine (PMDETA), tris [2-(dimethylamino)ethyl] amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridyl- methyl)amine (TPMA), 1,1, 4, 7, 10,10-hexamethyltri ethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1,4.8.11 -tetramethyl- 1.4.8.11-tetraazacyclotetradecane (Me4Cyclam), and / or 2,2’ -bipyridyl (BiPy). Other ligands may include 1,4, 8,11-tetraazacyclotetradecane (Cyclam), 1,8-dimethyl-l, 4, 8,11-tetraazacyclotetradecane (Me2Cyclam), 1,4,7,10- tetraazacyclododecane (Cyclen), and different methylated Cyclen derivatives, and combinations thereof. The amount of ligand in the reaction composition is defined as a ratio to the concentration of catalyst in the reaction composition. The ratio of ligand to catalyst in the reaction composition is in the range 0.001 :1 to 1000: 1. The ratio of ligand to catalyst in the reaction composition may be in the range 0.005: 1 to 100: 1, for example 0.13:1, 0.5: 1, 1.0: 1, 2.0:1, 3.5: 1, 7.5: 1 or 12:1. In general, an excess amount of ligand as compared to amount of catalyst is preferred.

[0094] The catalyst and the ligand form a complex. One, two, three or even four ligands may form complexes with one catalyst. Suitable catalyst / ligand complexes include, but are not limited to, Cu / PMDETA, Cu / MeeTREN, Cu / TREN, Cu / TPMA, Cu / HMTETA, Cu / TMEDA, Cu / Me4Cyclam, and Cu / BiPy.

[0095] The reaction composition may in some cases comprise a halide compound for increasing the “livingness” of the polymerization of monomers. A “living” polymerization refers to a polymerization where the rate of termination is minor in comparison to the rate of propagation of polymer molecules from the polymerization initiators. As a result, living polymerizations show a T1 more linear relationship between polymer chain length and time. The halide compound to be used herein is a compound capable of providing a halide anion. Non-limiting examples of such compounds are NaCl, NaBr, KC1, KBr, MgCb, MgBr2, CaCh, HC1, HBr, LiCl, LiBr, CaBn, as well as combinations thereof. Halide compounds may disassociate in the reaction composition, generating halide anions which may form complexes with and / or bind to catalysts in solution, resulting in an increased concentration of catalyst / ligand-X (X is the halide anion) complexes which are responsible for end-capping, and thus deactivating, propagating surface polymer chainend radicals to deliver alkyl halides. Consequently, the number of propagating surface polymer chain-end radicals at any given time is lowered, which may result in at least the following effects, (1) a lowering of the rate with which polymer molecules grow initially due to a lower number of propagating chains, and (2) a lowering of the rate with which chain termination between two propagating polymer molecule chain-end radicals occur (through recombination or disproportionation), leading to an increased living character of the polymerization. In an embodiment, the catalyst is Cu, the ligand is MeeTREN, PMDETA, TREN, HMTETA, TPMA, TMEDA, or Me-iCyclam and the halide compound is NaCl.

[0096] The reaction composition may further comprise a buffer. Buffers usually are aqueous. Suitable buffers include carbonate buffers, glycine buffers, citrate buffers, phosphate buffers, acetate buffers, ammonium buffers (ammonium chloride / ammonia), formate buffers, sodium ascorbate / ascorbic acid buffers, and / or zwitterionic buffers such as Good’s buffers. Good’s buffer include MES, PIPES, MOPS, HEPES, CHES, CAPSO and / or CAPS. The buffer may provide stabilization of the reaction composition during the surface polymer formation.

[0097] The reaction composition for surface polymer formation may further be pH controlled. That is, an acidic or alkaline substance may be added one or more times to the reaction composition prior to or during surface polymer formation. The pH of the reaction composition may depend on acid dissociation constant of the complex formed between the catalyst and the ligand complexes. pH control is described further in WO 2024 155981, which is incorporated herein by reference. To meaningfully determine pH and / or pKa, the reaction composition may in general be aqueous, i.e., meaning that water is present in a certain amount. The second solvent of the reaction composition may suitably be water. Since the catalyst / ligand complexes mentioned herein are alkaline, the term pKaH is used, which refers to the pKaof the conjugate acid. The higher the pKaH value, the stronger the base. For species which may be protonated more than once pKaHi refers to the pKa of the conjugate acid obtained after the “first” protonation, and pKaHz refers to the pKa of the conjugate acid obtained after the “second” protonation; pKHi is in this case always higher than pKaH2, i.e., pKaHi > pKaH2. Specific pKa and pKaH values may be calculated using known titration methods, or, where available, be looked up in various publications and handbooks. Nonlimiting examples of alkaline substances are potassium hydroxide (KOH), lithium hydroxide (LiOH), tripotassium phosphate (K3PO4), sodium carbonate (Na2COs), or sodium ethoxide (CH3CH2ONa). Non-limiting examples of acidic substances are methanesulfonic acid (MSA), hydrochloric acid (HC1), sulfuric acid (H2SO4), phosphoric acid (H3PO4), 2,2,2-trifluoroacetic acid (TFA). -toluenesul Tonic acid (pTSA), and nitric acid (HNO3).

[0098] The reaction composition may further comprise an additive in the form of a surfactant and / or a polyquatemium compound. Suitable surfactants include sodium dodecyl sulfate (SDS), Triton- Xi 00, dioctyl sodium sulfosuccinate (DOSS), cetrimonium bromide (CTAB), cetrimonium chloride (CTAC), and / or dimethyldioctadecylammonium chloride. Suitable polyquatemium compounds include polyquatemium-7. polyquatemium- 10, polyquatemium-11, polyquatemium- 14. polyquatemium-D16, polyquatemium-31, polyquatemium-36, polyquatemium-46, poly- quatemium-65, polyquatemium-68, polyquatemium-79.

[0099] The formed surface polymer may be cross-linked. “Chains” of surface polymers on the surface of the substrate may be cross-linked via several pathways, depending on their structure and chemical functionalities. Generally, a cross-linking molecule must be able to either react at least with two reactive groups present in the polymer molecules, or, be able to react at least once with reactive groups present in the surface polymer and generate in this reaction at least one new reactive group, which may react further with neighboring chains of the surface polymer, leading to cross-linking. As an example of the latter, poly(glycidyl methacrylate) (PGMA) contains a reactive oxirane(epoxide)-moiety, which upon reaction with a nucleophile (Nu) yields a hydroxyl group, and a carbon-Nu covalent bond. The formed hydroxyl group may itself be considered a nucleophile and can react with another oxirane moiety of a neighboring polymer molecule, resulting in formation of a carbon-0 covalent bond, which is responsible for the cross-linking of two chains of surface polymers. Suitable nucleophiles for reaction with PGMA include but are not limited to amines, thiols, hydroxyls. Examples of nucleophiles which may react only once with PGMA surface polymer chains include alcohols such as ethanol and phenol, secondary amines such as diethylamine, and thiols such as 1 -decanethiol. Examples of nucleophiles that may react at least twice with PGMA surface polymer chains include primary' amines such as allyl amine and propyl amine, diamines such as 1 ,2-diaminoethane, diols such as ethylene glycol and bisphenol A, and dithiols such as ethylene bis(thioglycolate). Cross-linkers which may react e.g. at least three times can be conceptualized by e.g. branched triamines such as propane- 1, 2, 3-amine, and glycerol. In order for a molecule to cross-link chains of surface molecules that contain nucleophilic functional groups such as hydroxyls and amines, the cross-linker molecule should comprise at least two reactive electrophilic sites. Examples thereof include di-acid halides such as succinyl chloride, adipoyl chloride, fumaryl chloride and azealoyl chloride, or dicarboxylic acids such as maleic acid, glutaric acid, and terephthalic acid, which may be activated by suitable reagents such as carbodiimides like l-ethyl-3-(3-dimethylaminopropyl)carbodiimide, diisopropylcarbodiimide. or N,N’ -dicyclohexylcarbodiimide, or acid halide forming species such as thionyl chloride.

[0100] The reaction composition comprises a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent. The first solvent may suitably be a “simple” alcohol like methanol (MeOH), ethanol (EtOH) and / or isopropanol (iPrOH). In some embodiments, the first solvent may suitably be a monomer having a hydroxyl functional group on an aliphatic carbon atom like 2-hydroxyethyl methacrylate (HEMA), 2-hydroxylethyl acrylate (HEA), 2-hy droxyethyl acrylamid, 2-hydroxypropyl methacrylate, and 2-hy droxy propyl methacrylamide. In some embodiments, the first solvent may be a combination of first solvents. Non-limiting examples include mixtures of methanol, ethanol and / or isopropanol. The second solvent may suitably be water. Here, “water” is intended to include deionized water, demineralized water etc. First and second solvents are herein expressed as volume percent (Vol%) relative to the volume percent of the reaction composition (Vol%Totai) according to the formula (I) and (II):

[0101] VolumeFirst solvent

[0102] Vol%(First solvent) = - (I)

[0103] VolumeTotai

[0104] Volumesecond solvent

[0105] Vol%(Second solvent) = - (II)

[0106] VolumeTotai

[0107] VolumeTotai is the volume of the first solvent, the second solvent, the monomer, the catalyst / ligand complex including any solvent, and the catalyst activator including any solvent.

[0108] The inventors have surprisingly found that choosing the Vol% of the first solvent can result in improved control over the surface polymerization. As shown in the Examples, the type and / or the amount of the first solvent provides the possibility of influencing the polymerization rate so as to approach or reach a plateau. The inventors believe that the first solvent surprisingly has a dampening effect on the polymerization rate as it has been observed that increasing Vol% of the first solvent provides a lowering of polymerization rate and also influences the average dry film thickness of the formed surface polymers. Furthermore, adjusting the Vol% of monomer and / or catalyst / ligand may surprisingly provide an additional dampening effect on the surface polymerization rate.

[0109] In an embodiment, the first solvent is present in the reaction composition in an amount of 20 Vol% to 80 Vol%, calculated according to formula (I) above.

[0110] Furthermore, the inventors have found that the dielectric constant, k, of the first solvent may provide a dampening effect on the polymerization rate. Thus, suitable first solvents may have a dielectric constant in the range of 5 to 80, depending on the amount of dampening required.

[0111] In some embodiments, the solvent may further comprise at least a third solvent. The third solvent may suitably be selected from aprotic solvents such as acetone, acetonitrile and / or dimethylsulfoxide (DMSO).

[0112] The methods described herein make possible the formation of surface polymers with a controlled average dry film thickness. The average dry film thickness may in general be any thickness, for example, up to 500 nm, or even 1000 nm. The methods described herein make possible the formation of surface polymers with an average dry film thickness in the range of up to 100 nm, for example in the range of 50 nm to 3 nm. This may be achieved by choosing the composition of the reaction composition to modulate the polymerization rate to follow a certain desired surface polymer propagation pattern (e.g., linear propagation, or reaching polymerization plateau). Thus, in one embodiment, the method may be such, wherein the formed surface polymer has an average dry film thickness of no more than 50 nm. In one embodiment, the method may be such, w herein the formed surface polymer has an average dry film thickness of no more than 25 nm. In one embodiment, the method may be such, wherein the formed surface polymer has an average dry film thickness of no more than 10 nm. In one embodiment, the method may be such, wherein the formed surface polymer has an average dry film thickness of no more than 5 nm. Suitably, the surface polymer may be formed within 30 second to 30 minutes.

[0113] While the term surface polymer is used to describe the molecules propagation on the surface of the substrate from the polymerization initiation sites, it should be appreciated that when the length of these molecules is only in the lower end of the 10s of nm scale, or the nm scale, these molecules may correctly be called oligomers when the definition provided by the IUPAC is observed to apply. An oligomer is “a molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass. Notes: A molecule is regarded as having an intermediate relative molecular mass if it has properties which do vary significantly with the removal of one or a few of the units. If a part or the whole of the molecule has an intermediate relative molecular mass and essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass, it may be described as oligomeric, or by oligomer used adjectivally.” See https: / / goldbook.iupac.org / terms / view / O04286.

[0114] Within the present context, the terms “surface polymer(s)” and “oligomer(s)” are also intended to encompass “polymer brush(es)”.

[0115] The present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, w herein the relative amounts of and / or types of the first solvent and the second solvent providing an average dry film thickness of at most 50 nm. The present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or ty pes of the first solvent and the second solvent providing an average dry film thickness of at most 25 nm. The present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of the first solvent and the second solvent providing an average dry film thickness of at most 10 nm. The present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of the first solvent and the second solvent providing an average dry film thickness of at most 5 nm.

[0116] In accordance with the above, the present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of at most 50 nm. In accordance with the above, the present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of at most 25 nm. In accordance with the above, the present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of at most 10 nm. In accordance with the above, the present disclosure provides a reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of at most 5 nm. As described above, the disclosure herein makes possible obtaining polymers formed on a surface of a substrate by the method described herein, wherein the applied relative amounts and / or types of the first solvent, and the second solvent are selected to modulate and / or control the rate of surface polymer formation.

[0117] As described above, the disclosure herein makes possible obtaining polymers formed on a surface of a substrate by the method described herein, wherein the applied relative amounts and / or types of two or more of the first solvent, the second solvent, monomer, the catalyst and ligand forming a catalyst / ligand complex, and the catalyst activator are selected to modulate and / or control the rate of surface polymer formation.

[0118] The inventors have shown that formulation of the reaction composition for surface polymer formation may unexpectedly influence or even alter the polymerization rate as well as the profile or trace (see Fig. 3 and Fig. 4) of the surface polymerization. Modulation of the amounts and / or types of other components (other than the first and the second solvent) of the reaction composition may further add to the modulate and / or control of surface polymer thickness.

[0119] The inventors have further shown that the rate of the surface polymer formation may be modulated so as to obtain a more living polymerization by selecting the type of catalyst / ligand complex to be a less active ligand when formulating the reaction composition. A less living surface polymerization may further be influenced by formulating the reaction composition so as to include an increased amount of first solvent.

[0120] Thus, in accordance with the above, a living polymerization rate may be converted to a less living polymerization rate. Likewise, a non-living polymerization rate may be converted to a more living polymerization rate.

[0121] The inventors have found that formulating the solvent of the reaction composition so as to include different Vol% of first and second solvent may be used to increase or decrease the average dry film thickness. Furthermore, the dielectric constant of the first solvent may have an influence on the average dry film thickness. The inventors have found that a plateauing polymerization rate profile (and the polymerization time at which the polymerization plateau is reached) may be modulated by formulating the reaction composition so as to comprise an increased or a decreased amount of first solvent. The higher the amount of first solvent, the lower average dry film thickness of surface polymers within a certain polymerization time interval. An example of this is Example 9, Fig. 15, in which an isopropanol (iPrOH) concentration of 53 Vol% leads to more than 60 nm surface polymer (average dry film thickness), while adjusting to 77 Vol% iPrOH leads to just 10 - 12 nm surface polymer (average dry film thickness). The average dry film thickness of the surface polymers formed at the polymerization plateau may further be modulated so as to shift the polymerization plateau (thicker or thinner surface polymer) by applying less monomer and more catalyst / ligand complex in the reaction composition. As an example, see Example 11. changing the monomer concentration in the reaction composition from 7.4 Vol% to 3.4 Vol% leads to almost half the average dry film thickness at the polymerization plateau. Applying a higher amount of catalyst in the catalyst / ligand complex in the reaction composition resulted in the following (see Example 6, Fig. 11): both 80 and 40 pM Cu led to similar average dry film thicknesses at the polymerization plateau, while 20 pM Cu led to a higher average dry film thickness at the polymerization plateau. In the case of formulating the reaction composition so as to include more first solvent being isopropanol (iPrOH) and less second solvent being DI- water, the following was observed: the average dr ' film thickness at the polymerization plateau may be modulated to yield surface polymers with average dry film thicknesses of above 60 nm and down to 10-12 nm by increasing the Vol% of first solvent from 53 Vol% to 77 Vol%, see Example 9. Inventors speculate that an even higher amount of first solvent may lead to lower average dry film thickness at the polymerization plateau. In case of formulating the reaction composition so as to include PMDETA ligand in the catalyst / ligand complex, tBMA as the monomer and isopropanol (iPrOH) as the first solvent, the slope of the linear surface polymer formation rate was be modulated by adjusting the Vol% of iPrOH, with 53 Vol% iPrOH leading to the steepest slope (fastest polymerization rate) and 77 Vol% leading to the flattest slope (slowest polymerization rate), see Example 8.

[0122] Fig. 8 is a non-limiting schematic illustration of a system 100 for forming surface polymers on at least a portion of a substrate. The system 100 comprises a reaction composition container 104 containing the aforementioned reaction composition 105. Container 104 may relate to any vessel or chamber suitable for holding the reaction composition. At least a portion of a polymerization initiator-modified substrate 102 is brought into contact with the reaction composition 105, for example by at least partly immersing a desired surface of substrate 102 into the reaction composition, thereby enabling surface polymers to form on the substrate.

[0123] Optionally, system 100, may comprise one or more further containers, each container comprising different compositions and / or agents for treating the substrate 102, either prior to the substrate being brought into contact with the reaction composition 105. or afterwards. Where substrate 102 has not been pre-treated with a polymerization initiator, then the system 100 may further comprise a container 106 holding a polymerization initiator chemistry 107, thus, forming the polymerization initiator-modified substrate 102 in the container 106. As mentioned above, a portion or portion of substrate 102 may be masked, e.g., by applying a film or a layer, so as to enable attachment of polymerization initiators only to a portion or portions onto which surface polymers are to be formed subsequently.

[0124] When Fig. 8 relates to an embodiment in which the substrate has been pre-coated with a polymerization initiator. In such embodiments, and as illustrated in Fig. 8, a cleaning container 114 may be provided, comprising a cleaning agent or cleaning device 116. The cleaning agent / device 116 may be used to clean the surface of substrate 102 prior to bringing it into contact with reaction composition 105 held by the reaction composition container 104. This may be achieved by, at the very least, subjecting at least a portion of the substrate 102 on which it is desired to form surface polymers on. to cleaning procedures in container 114 using cleaning agent / device 1 16. In this way, any impurities which may interfere with the formation of the surface polymers, are removed from the surface of substrate 102, prior to bringing substrate 102 into contact with the reaction composition 105. System 100 may additionally include a substrate displacement device 103 for bringing the substrate 102 at least partly into contact with the reaction composition 105 held by the reaction composition container 104 for a controlled time to ensure surface polymers form. The expression “at least partly” is intended to mean that a portion or portions of substrate 102 is brought into contact with the reaction composition 105. The displacement device 103 may be configured to control the contact between substrate 102 and reaction composition 105. Alternatively, as mentioned above, the portion or portions of substrate 102 may be covered (“masked”) by, e.g., a film or a layer suited for avoiding contact between reaction composition 105 and the substrate 102. The displacement device 103 may be used to remove the substrate 102 from the reaction composition 105 following surface polymer formation. Thus, the substrate displacement device 103 may be configured to maintain the surface of substrate 102 at least partly in contact with the reaction composition 105 to enable surface polymers to form on at least a portion of the surface of the substrate, and the substrate displacement device 103 may be configured to maintain the substrate 102 in contact with the reaction composition 105 for a predetermined amount of time.

[0125] In embodiments where the system 100 may comprise two or more containers, such as illustrated in Fig. 8, in addition to bringing substate 102 into contact with the compositions contained by each container, the substrate displacement device 103 is configured to transport substrate 102 to and from each container. For example, as illustrated in Fig. 8, the substrate displacement device 103 is configured to first transport substrate 102 into contact with cleaning agent / device 116 in container 114, and / or a polymerization initiator composition 107 if the substrate is not pre-coated with a polymerization initiator as mentioned previously, held in the polymerization initiator container 107, and subsequently to transport the substrate 102 from the polymerization initiator container 107 to the reaction composition container 104, where the substrate is brought at least partly into contact with the reaction composition 105 held by the reaction composition container 104. In the latter example, the substrate may in embodiments be cleaned between initiator coating and surface polymer formation.

[0126] System 100 as shown in Fig. 8 may further be equipped with a reaction composition management system (not shown). The reaction composition management system may include one or more sensors in relation to the reaction composition container 1 4. The one or more sensors may be configured to measure a characteristic of the reaction composition 105, which characteristic may relate to a physical or chemical characteristic of the reaction composition 105, such as the pH of the reaction composition or the molecular oxygen concentration in the reaction composition. The sensor data may be used to determine whether a value of the measured characteristic lies within a predetermined threshold for the surface polymer formation process. If the measured characteristic is determined to lie outside the predetermined threshold, then the chemistry of the reaction composition 105 may be adjusted by dispensing different chemistries to reaction composition container 104 to adjust the value of the measured characteristic, e.g., an acidic or an alkaline substance to adjust the pH value of the reaction composition 105 or a substance to control the oxygen concentration of the reaction composition 105. In this way, it is possible to ensure that the values of the one or more characteristics of the reaction composition are within a range suitable for forming desired surface polymers on the substrate 102. A control unit operatively connected to the one or more sensors, may be used to control one or more dispensers for dispensing one or more chemistries to control the chemistry of the reaction composition 105.

[0127] Similarly, the chemistry of the reaction composition 105 may be adjusted by dispensing any one or more of the components of the reaction composition into the reaction composition 105. For example, the components may relate to any one or more of: at least one monomer, at least one ligand, at least one catalyst, at least one catalyst activator, and at least one solvent. In some embodiments, the control unit may be configured to output a control signal for controlling operation of a dispenser for dispensing one or more components of the reaction composition into the reaction composition 105, in response to the measured characteristic of the reaction composition 105. or in response to an observed time variance of the characteristic. For example, a value of the measured characteristic may be monitored over a time period using the one or more sensors. The control unit may determine to output a control signal to control operation of one or more dispensers to dispense the one or more components on the basis of an observed variation over time of the measured characteristic. The observed variation may be indicative that the chemistry of the reaction composition 105 is varying such that the surface polymer formation process is falling out of specification - for example, surface polymer formation is reduced and / or compromised. The dispensing of one or more components of the reaction composition into the reaction composition 105 may help to maintain one or more chemical properties of the reaction composition 105. to enable the formation of surface polymers. In some embodiments, dispensing of the one or more control agents and / or components of the reaction composition may occur periodically. In such embodiments, sensor measurement data may be used to ensure the chemical and / or physical characteristics of the reaction composition 105 are as desired. However, dispensing of the one or more control agents and / or components of the reaction composition, and more specifically the outputting of one or more control signals by the control unit to control the dispensers, may be independent of any specific sensor measurement. (The latter method of maintaining the reaction composition 105 may be based on known rates of consumption of components of the reaction composition or on known variation over time of pH or molecular oxygen concentration, for example.) In yet further embodiments, dispensing of the one or more agents and / or components of the reaction composition, and more specifically the outputting of one or more control signals by the control unit, may be directly dependent on one or more measured characteristics of the reaction composition 105. Similarly, the outputting of one or more control signals by the control unit to control dispensing of the one or more control agents and / or components of the reaction composition may be dependent on a measured sensor signal indicative of a change in a measured characteristic of the reaction composition 105. Combinations of some of these different methods may also be advantageous, for example using dispensing of agents and / or components for maintenance of the reaction composition 105 over shorter time intervals without use of sensor measurements, combined with adjustments being made based on regular sensor measurements made at longer time intervals.

[0128] In some embodiments it may be advantageous to control the environmental conditions in which the system 100 is implemented, and in particular in which the surface polymers are formed. For example, this may help to reduce contaminants and other impurities contaminating the reaction composition 105 and / or the substrate 102. Non-limiting examples of contaminants and impurities may include bulk polymers or metals. Similarly, controlling environmental conditions such as, but not limited to, pressure, temperature, humidity, and / or inert atmosphere, may be beneficial to the process for forming surface polymers. To achieve this, in some embodiments, system 100 may be implemented in an environmentally controlled chamber. For example, the aforementioned containers may sit within one or more environmentally controlled chambers. In some embodiments all of the containers may sit within one or more chambers. In some embodiments a subset of the containers may sit within one or more chambers. For example, it is envisaged that in some embodiments the polymerization initiator container may sit within a chamber, whilst the reaction composition container 104, may sit outside a chamber. Similarly, in some embodiments it is envisaged that cleaning of the substrate prior to polymerization initiator formation may also occur in an environmentally controlled chamber, in which case the associated cleaning agent container also could sit within an environmentally controlled chamber.

[0129] The substrate displacement device 103 may relate to any device capable of transporting the substrate from one container to another container. For example, the substrate displacement device 103 may relate to a mechanical device. In particular, it is envisaged that the substrate displacement device 103 may comprise any one of: a conveyor system, a programmable mechanical arm, and / or a roll-to-roll processor / mechanism.

[0130] A conveyor system as used herein may refer to a mechanical system that is used to move a material, such as the substrate, which in embodiments may be in a substrate holder on its own or with other substrates, from one process container to another, typically comprising a movable conveyor, powered by a drive system and having a series of rollers or pulleys that support and guide the belt. In use, the substrate may be placed on the conveyor which passes the substrate through the one or more containers comprised in the system. In this way, as the conveyor is powered, the substrate is passed through the component(s) held by each container within the system. Furthermore, in some embodiments the containers are enclosures in which the reaction composition, or other appropriate wet chemistry’, is uniformly applied over the substrate using spray nozzles.

[0131] In some embodiments a programmable mechanical arm, such as a robotic arm, may be used to transport the substrate, which may be in a holder as described above.

[0132] A roll-to-roll processor or mechanism is particularly advantageous for use where the substrate may be flexible and elongated, such as a cable, wire, foil, sheet or any other elongated flexible substrate. Fig. 9 illustrates such an embodiment, in which the substrate displacement device relates to a roll- to-roll processor 118, comprising a sending roll 121, a receiving roll 122 and a plurality of rollers 120. At least some of the rollers 120 and the receiving roll 122 are driven, thereby enabling a flexible elongated substrate 123 to be passed from the sending roll 121 through the reaction composition 105 in container 104 to the receiving roll 122. The roll-to-roll mechanism can be utilized as a replacement to the substrate displacement device 103 in Fig. 8 when elongated flexible substrates are being processed. In some embodiments, the substrate may be masked in certain areas to form surface polymers only from unmasked polymerization initiator. In some embodiments, polymerization initiator sites may only be attached at certain portion(s) on the substrate as described above. In some embodiments, only the portion(s) of the substrate is immersed into the reaction composition to form surface polymers on the portion(s) of the substrate being in contact with the reaction composition. In some embodiments, forming surface polymers on portion(s) of the substrate may be a combination of masking and bringing only the desired portion(s) of the substrate in contact with the reaction composition. The substrate displacement device or another type of substrate displace device may be suited for carry ing out the specific contact between the substrate and the reaction composition.

[0133] In yet further embodiments, at least one of the plurality of containers may comprise an annealing oven for annealing the formed surface polymers. In a similar manner as described previously, the substrate displacement device 103 may be configured to transport the substrate with the formed surface polymers to the annealing oven 109 and to bring the substrate with surface polymers into position for annealing. The annealing oven is equipped with a heating device for annealing the formed surface polymers and the gas environment 111 in the oven may be controlled as needed - for example, to avoid oxidation by using only non-oxidizing gases.

[0134] According to embodiments, a system for forming surface polymers on a substrate may comprise: a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts to the balance of the amount of the reaction composition and / or types of two or more of the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation, and a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers of a specified average dry film thickness to be formed on the portion of the polymerization initiator- modified substrate. Furthermore, the substrate displacement device may comprise any one of: a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism. Furthermore, the system may comprise a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is configured to bring the portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition. Furthermore, the system may comprise one or more cleaning containers, the cleaning containers containing cleaning agents, wherein the substrate displacement device is configured to bring the portion of the polymerization initiator-modified substrate into contact with the cleaning agent prior to, or subsequent to, bringing the portion of the polymerization initiator-modified substrate into contact with the reaction composition, or the substrate displacement device is configured to bring the portion of substrate into contact with the cleaning agent prior to. or subsequent to. bringing the portion of the substrate into contact with the polymerization initiator. Furthermore, extra containers may be added as needed for rinsing, etc. between processes. The substrate displacement device may be one or more robots or a conveyor system with the capability to move substrates horizontally and vertically in and out of containers and from container to container. In some embodiments, system 100 may include one or more containers holding a chemistry' for pre-wetting the substrate 105 prior to bringing the substrate 105 into contact with the reaction composition 105 in the reaction composition container 104. The pre-wetting chemistry may essentially correspond to the reaction composition 105, however, without the catalyst activator, for example, to pre-wet the surface but not induce polymerization reaction. In some embodiments, the pre-wetting chemistry’ may include one or more components to enhance pre-wetting of the substrate 102, for example, a composition of solvent differing from the reaction composition 105. The pre-wetting of the substrate 105 may facilitate homogeneous formation of particularly "thinner" surface polymers, that is, surface polymers of at most 50 nm, at most 25 nm, at most 10 nm, or at most 5 nm.

[0135] In some embodiments, each container of system 100 may include flow control devices, such as, for example, circulation pumps, flow guidance grids, filters, and / or mechanical stirring means. The flow control devices may facilitate distribution of the chemistry’ in a container around the substrate 102, and may in some cases be useful for filtering off potential contaminants.

[0136] Aspects and embodiments of the disclosure are further illustrated by' the following, non-limiting examples.

[0137] Examples

[0138] Throughout the examples, Dl-water refers to tap water deionized using the deionizing equipment (Silhorko with M22-F softening plant, RO Bl -2 Reverse Osmosis plant and Silex 2BS mixed bed plant). The Dl-water has a conductivity of <0.5 pS / cm, indicating an ultrapure quality with very' low presence of ions. The quality of the Dl-water is confirmed at least weekly. Dl-water holds a conductivity of less than 0.5 pS / cm, indicating very low presence of ions, below 0. 1 mg / L.

[0139] Silicon wafer substrates, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), were purchased from MicroChemicals GmbH (r = 5.08 cm) and cut into l / 4th of a wafer.

[0140] Ammonia (25% p. a) was purchased from Chemsolute.

[0141] Hydrogen peroxide (30%, stab.) was purchased from Chemsolute.

[0142] Acetone (>99%) was purchased from Chemsolute.

[0143] Acetonitrile (MeCN) (min. 99.9 %) was purchased from Chemsolute.

[0144] Dimethylsulfoxide (DMSO) (> 99 %) was purchased from Toky o Chemical Industry. Dioxane (min. 99.5 %) was purchased from Chemsolute. ABC clean A200 was purchased from ABC-Clean ApS. / 7-(Chloromethyl)phenyltrimethoxysilane (CPTMS) (95%) was purchased from Gelest. Tris[2-(dimethylamino)ethyl]amine (Me6TREN) (>98% ) was purchased from abcr or Alfa Aesar. Tris(2-pyridylmethyl)amine (TPMA) (98%) was purchased from Tokyo Chemical Industry.

[0145] N,N,N',N",N''-Pentamethyldiethylenetriamine (PMDETA) (99%) was purchased from Sigma Aldrich.

[0146] Copper(II)chloride dihydrate (CuC12-2H2O) (99.0%) was purchased from Sigma Aldrich.

[0147] Methyl methacrylate (MMA) (99 %, 30 ppm MEHQ inhibitor) was purchased from Sigma Aldrich (lot no. STBK8834).

[0148] Glycidyl methacrylate (GMA) (> 97 %) was purchased from Sigma Aldrich. te / 7-Butyl methacrylate (tBMA) (>98.0%) was purchased from Sigma Aldrich. Sodium ascorbate (NaAsc) (98%) was purchased from Sigma Aldrich.

[0149] List of catalyst solutions:

[0150] Catalyst M: Me6TREN (76 LIL). Dl-water (15.924 mL), and Cu(II) (324 mg / L, obtained from a solid copper source by stirring or otherwise mixing prior to mixture with ligand and Dl-water).

[0151] Catalyst T: TPMA (84 mg), Solvent 1 (7 mL) and 9 mM CuC12 2H2O (aq.) (9 mL).

[0152] Catalyst P: PMDETA (0.06 mL), CuC12-2H2O (13.6 mg) and Dl-water (16 mL).

[0153] List of equipment used in the Examples:

[0154] “Big sonicator ’ refers to an ULTRASONIC CLEANER PROCLEAN 28.0 from Ulsonix (40 kHz, 480 W).

[0155] “Sonicator” refers toto a Bandelin Sonorex Super RK100 sonicator (35 kHz ultrasound frequency, 80 W nominal ultrasonic power).

[0156] “Vacuum oven” refers to a Faithful Vacuum Drying Oven-DZ-BCII.

[0157] “Oven” refers to a Binder model FD 56.

[0158] Ellipsometry was measured on a J. A. Woollam M-2000 Ellipsometer. This instrument was set to measure 10 points on each substrate, unless otherwise indicated. Each point was analyzed using a Cauchy model providing a thickness and a Mean Square Error (MSE). the latter referring to the goodness of the fit. Thicknesses are thus given as the average of all measured points on the substrate (average dry film thickness). Unless specifically stated otherwise, 10 data points were obtained on each sample. Standard deviation is the standard deviation based on the entirety of the measured thicknesses. The standard deviation is an estimate of the homogeneity of surface polymers formed. The coefficient of variation (CV) can be calculated as the standard deviation divided by the average dry film thickness. The CV is the size of the standard deviation relative to the average dry film thickness, making it a dimensionless number (reported as a percentage below) making the CV good measure when comparing different data sets. To obtain detailed datasets of surface polymer thickness from which lateral maps of average dry film thickness can be produced, the ellipsometer instrument can be equipped with focusing optics (J. A. Woollam), reducing the beam spot size (the measured area) from 300 pm x 710 pm to 30 pm x 71 pm at a 65 degree angle of incidence. The much smaller beam size enables measurement of many more points on a substrate, enabling a higher resolution of the average dry film thickness.

[0159] Infrared Reflection Absorption Spectroscopy (IRRAS) was measured on a Nicolet 6700 FTIR Spectrometer (Thermo Fisher Scientific. Denmark), equipped with a liquid nitrogen-cooled narrow-band mercury cadmium telluride (MCT / A) detector. The spectral resolution was 4 cm- 1, and 100 spectra were recorded and averaged for each measurement. The spectra were recorded in dry air, at room temperature. The substrates were irradiated with p-polarized light, at an angle of approximately 65°. The spectra were baseline corrected using the OMNIC 8.2 software.

[0160] Water contact angles (WCA) were measured on a Krtiss Mobile Surface Analyzer. In 5 separate points, the contact angle of a Dl-water and a CH2I2 drop is measured. Using the software ADVANCED v. 1.14, the surface free energy (SFE) can be calculated. The SFE indicates the maximum surface tension of a liquid that wets a solid surface, under ideal conditions. Accordingly, a material with a high SFE is easier to wet than a material with a lower SFE, and low SFE materials will generally exhibit higher water contact angles than those materials with a higher SFE.

[0161] Example 1

[0162] Pre-cleaning of silicon wafers

[0163] This example describes a procedure for pre-cleaning of substrates for surface polymer formation. The total number of substrates may vary depending on the later application.

[0164] Silicon wafer substrates (r = 5.08 cm, cut to l / 4thof a wafer, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), purchased from MicroChemicals GmbH) were cleaned prior to further processing using the following method:

[0165] Racks containing the substrates were placed in an aqueous solution of ammonia (15 Vol% DI- water / 85 Vol% ammonia) and sonicated for 10 minutes in a big sonicator. Then, the substrates were flushed with Dl-water, and sonicated in DI- water for 10 minutes. Thereafter, the racks containing the substrates were transferred to a 5% solution of ABC clean and sonicated for 10 minutes at in a big sonicator. This step was followed by flushing the substrates in Dl-water and sonicating the substrates in Dl-water for 5 minutes with previously described equipment. Finally, the substrates were flushed with acetone, and left to dry at room temperature or in an oven at 80°C for 15 minutes.

[0166] Example 2

[0167] Chemical vapor deposition of (p-chloromethyl)phenyltrimethoxysilane (CPTMS) at 45°C

[0168] This example illustrates a procedure for covalently attaching polymerization initiators on a substrate.

[0169] Silicon wafer substrates as described in Example 1, cleaned as described in Example 1, were used for surface modification with CPTMS polymerization initiators using a chemical vapor deposition method.

[0170] The substrates were placed in a rack and placed in a vacuum oven with 16 vials of 100 pL CPTMS at approximately 45°C for 150 minutes. The gauge pressure was lowered to -1.0 bar, whereby the CPTMS evaporated, and the substrates were left for 150 minutes. Thereafter, the substrates were removed and placed in an oven at approximately 80°C for 15 minutes to anneal the silane layer. After annealing, the substrates were stored in ambient conditions and left for 24 hours.

[0171] Ellipsometry measurements before and after the deposition of the CPTMS molecules do not show significantly different surface layer thickness on the wafer, indicating formation of a thin polymerization initiator layer. Thus, the layer thickness from the CPTMS initiator molecule is at most expected to contribute to the overall thickness following surface polymerization with 1.7 nm.

[0172] Example 3

[0173] Chemical vapor deposition of (z?-chloromethyl)phenyltrimethoxysilane (CPTMS) at 100°C

[0174] The example illustrates a procedure for covalently attaching polymerization initiators on a substrate (in this case Si substrate). Silicon wafer (Si) substrates, pre-cleaned as described in Example 1, were used for surface initiator-modification with CPTMS polymerization initiators using a chemical vapor deposition method.

[0175] The substrates were placed in a rack and placed in a vacuum oven with 16 vials of 100 pL CPTMS (polymerization initiator liquid) at approximately 100°C for 30 minutes. The gauge pressure was lowered to -1.0 bar, whereby the CPTMS evaporated, and the substrates were left for 30 minutes in the vapor. Thereafter, the substrates were removed and left for 24 h to anneal the silane layer.

[0176] Ellipsometry measurements before and after the deposition of the CPTMS molecules do not show significantly different surface layer thickness, indicating formation of a thin layer. Thus, the layer thickness from the CPTMS initiator molecule is not expected to contribute in a significant way to the average dry7film thickness.

[0177] Example 4

[0178] Method for assessment of surface polymer forming ability (rate study) of a reaction composition This example illustrates a procedure for assessing the rate with which surface polymers are formed over time in a reaction composition. This procedure serves as a reference in subsequent examples.

[0179] Silicon wafer substrates (same grade as described in Example 1) were pre-cleaned as described in Example 1 , and polymerization initiators were attached on the surface as described in Example 2 or Example 3. The substrates were then immersed simultaneously in the reaction composition, and individually recovered from the reaction composition according to the following procedure. At minute 0, defined as 5 minutes after addition of (a solution of) catalyst activator (NaAsc), all substrates were immersed into the reaction composition. At subsequent timestamps, typically at 2, 5, 7.5, 10, 20, and 40 minutes, one substrate was withdrawn from the reaction composition, immediately rinsed and dried as described below, at each instance from the reaction composition. In this way, 6 substrates subjected to the same reaction composition but for different durations of polymerization time were obtained, allowing for the assessment of the surface polymer growth as a function of time. After surface polymer formation and withdrawal from the reaction composition, the substrates were cleaned by sonication in Dl-water for 5 minutes, followed by sonication in acetone for 5 minutes. The substrates were allowed to dry in ambient air.

[0180] After cleaning and drying the surface polymerized substrates, the average dry film thicknesses of the formed (collapsed) surface polymers were analyzed using ellipsometry’. For each substrate, the average dry film thicknesses (in nm) of the surface polymers were plotted against time (in minutes) at which the substrate was recovered. In this way, the rate of surface polymer formation was evaluated as a function of polymerization time. From here, the “rate” of a given reaction composition is referred to as the average dry film thickness (in nm) of surface polymers which were obtained as a function of polymerization time.

[0181] Example 5

[0182] Effect on surface polymer formation by varying the composition of the solvent

[0183] In this example, the inventors illustrate the influence on the formation of surface polymers by changing the composition of the solvent (first solvent and second solvent), and, thus, modulation of the obtained average dry film thickness. 5 different compositions of the solvent (Dl-water and EtOH) were evaluated as shown in Table 1.

[0184] In a glass container (Container C), Catalyst T was prepared by' dissolving CuCk 2H2O (13.64 mg) and TPMA (84.21 mg) in Solvent 1 (EtOH, 7 mL) and Solvent 2 (Dl-water, 9 mL)

[0185] To a glass container (Container A) was added Catalyst T (16 mL), Solvent 2 (Dl-water (second solvent)) and Solvent 1 (EtOH (first solvent)) in varying volume as defined in Table 1. The volumes are reported in percentage to the total volume of the final reaction composition (see formula (I) and (II) below), where Volumesoiventi is the volume of the first solvent, Volumesoivent2 is the volume of the second solvent, and Volumeiotai is the total volume of the final reaction composition (Solvent 1, Solvent 2. catalyst / ligand complex solution including any Solvent 1 and / or Solvent 2, monomer, and catalyst activator including any Solvent 1 and / or Solvent 2). The solution was sonicated for 5 minutes.

[0186] Volumesoiventi

[0187] Vol%(Solvent 1) =

[0188] VolumeTotai In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes. Then GMA monomer (75 mL) was added to Container A. The content of Container A was poured into a reaction container.

[0189] For each reaction IDs. 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS), pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2 were placed in the reaction container, and one substrate was withdrawn at a certain time, according to Table 2, to conduct a rate experiment as described in Example 4. Below, the average dry film thicknesses obtained at each time, for each solvent composition, are reported in Table 2. The data sets from each Reaction ID are reported with an R2value, this value is the coefficient of determination obtained by fitting the data set to a linear regression, of the form y=a«x+b. where the inventors ascribe the value of b, the y-intercept, to the thickness of the CPTMS initiator layer, and lock this value at 1.7 nm for the entirety of the subsequent examples. Additionally, a TMIN / TMAX is reported; TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes (TMIN) and 40 minutes (TMAX) and is used to evaluate if a plateau has been reached. It is understood that as TMIN / TMAX approaches a value of 0.8 the polymerization plateau is considered reached.

[0190] Table 1 : Specific volume of Dl-water and EtOH in Container A for Reaction ID 5. 1-5.8. Note: ID 5.2 and 5.3 are replicas of ID 5.1 , and ID 5.6 is replica of ID 5.5. Table 2: Polymerization times and corresponding average dry film thickness and standard deviation for a series of solvents of Table 1. R2values based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to the 1.7 nm of the CPTMS initiator layer. TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes (MIN) and 40 minutes (MAX), used to evaluate if a plateau has been reached. Note:

[0191] ID 5.2 and 5.3 are replicas of ID 5.1, and ID 5.6 is replica of ID 5.5.

[0192] Fig. 10 is a plot of average dry film thickness as a function of polymerization time for 5 different solvent composition ratios of DI water and ethanol (Reaction IDs 5.1-5.3, 5.4, 5.5-5.6, 5.7 and 5.8). As observed from Fig. 10, the overall polymerization activity lowers with an increasing volume percentage of Solvent 1 (EtOH). Amazingly from the results shown in Table 1, Table 2 and Fig. 10, the inventors confirm the influence on the formation of surface polymers by changing the composition of the solvent: Increasing the concentration of Solvent 1 (EtOH) leads to a significantly lower average dry film thickness of formed surface polymers. This was observed for otherwise identical conditions regarding both composition of components (ligand, activator, catalyst, monomer) and polymerization time. Surprisingly, increasing Solvent 1 (EtOH) content from 35% to 38%, a 3- percentage point change, leads to an average dry film thickness with ~40 percentage points lower average dry film thickness after a polymerization time of 20 minutes. Moreover, the average dry film thickness obtained after 20 minutes polymerization time in a reaction composition comprising 35% Solvent 1 is 106 nm (average), while the average dry film thickness of the formed surface polymer using 49% Solvent 1 (an increase of 14 percentage points) is 11.5 nm, or a change of (1 - (11.5 nm / 108 nm) = 89.4%). A non-linear rate is observed for all data sets, seen from R2< 0.95 in all cases (Table 2). From TMIN / TMAX reported in Table 2, it is also concluded that all data sets (except ID 5.7) have reached a plateau. For ID 5.7 TMIN / TMAX = 0.78, hence it is approaching a plateau.

[0193] The trend of lower average dry film thickness with increasing EtOH content extends to all average dry film thickness yielded from the rate experiments reported above. Curiously, with a very small adjustment to the overall reaction composition as regards to solvent, major changes in the polymer average dry film thickness are observed, while the rate of the evolution of average dry film thickness over time remains similar (i.e. rapid growth in average dry film thickness at short polymerization times (A), and a lower rate of polymer propagation at longer polymerization times (B), as can be seen in Fig. 7). This trend of a plateau developing in average dry film thickness after a certain polymerization time is a useful feature in combination with the discovered impact that the Vol% of Solvent 1 (EtOH) has on the specific surface polymer thickness. It is noted that the replicas show similar average dry film thicknesses having regard to the standard deviation, and, thus, confirm the repeatability7of the polymerization.

[0194] Interestingly, it thus appears that the solvent composition of the reaction composition is a useful and readily accessible tool for pre-determining the average dry film thickness. The inventors recognize that despite the high complexity7of the effect of the solvent composition, manipulation thereof is an effective tool to achieve surface polymers with average dry film thicknesses below 50 nm or above 50 nm. Example 6

[0195] Effect of catalvst concentration on surface polymer formation when the ligand is TP MA

[0196] Based on the finding of Example 5, namely that the average dry film thickness at the plateau may be modulated by solvent composition, the inventors selected one solvent composition from the conditions tested in Example 5, and for this solvent composition, varied the catalyst / ligand complex concentration to establish the impact thereof on the rate of surface polymer formation, and the final average dry film thickness. While it may initially be expected that less catalyst should lower the rate of surface polymer formation, the intricate interplay between propagating and dormant chain ends, and the activating and deactivating catalyst species renders predicting the average dry film thickness trends as a function of catalyst / ligand complex concentration a challenging task.

[0197] In a glass container (Container C), Catalyst T was prepared by dissolving CuCh 2H2O (amount according to Table 3) and TPMA (amount according to Table 4) in Dl-water (according to Table 3) and EtOH (according to Table 3).

[0198] To a glass container (Container A) was added Catalyst T (according to Table 4), Dl-water and EtOH in varying volumes as defined in Table 4. The solution was sonicated for 5 minutes.

[0199] In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes. Then GMA monomer (75 mL) was added to Container A. The content of Container A was poured into a reaction container.

[0200] For each reaction IDs, 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS), pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2 were placed in the reaction container, and one substrate was withdrawn at a certain time, according to Fig. 11, to conduct a rate experiment as described in Example 4. Below, the average dry film thicknesses of obtained surface polymers at each time, for each solvent composition, are reported in Table 5. Table 3. Compositions for Catalyst T for the three different catalyst / ligand concentrations tested.

[0201] Table 4. Solvent and catalyst / ligand compositions for conditions evaluated.

[0202] Table 5. Polymerization times and corresponding average dry film thickness and standard deviation for the series of catalyst / ligand compositions of in Table 3 and Table 4.

[0203] In Fig. 11. average dry film thickness as a function of polymerization time for three different catalyst T concentrations is shown. As observed from Fig. 11, the overall reaction activity can be increased by significantly lowering the catalyst concentration.

[0204] Surprisingly, in accordance with Fig. 11 and Table 5, changing the catalyst concentration from 80 pM (Reaction ID 6.3) to 40 pM (Reaction ID 6.2) does not appear to have a significant impact on the average dry film thickness in this setup. However, decreasing the catalyst / ligand complex concentration further to 20 pM (Reaction ID 6.1) leads to a changed rate profile with a higher average dry film thickness at the plateau (54 nm to 90 nm). Thus, this experiment illustrates that the catalyst concentration influences the rate of surface polymer formation as well as the average dry film thickness of the surface polymer at the plateau. The inventors recognize the relation between the average dry film thickness and catalyst / ligand complex concentration is not straightforward, given the intricate interplay between activating and deactivating catalyst / ligand complex species in the reaction composition, and the number of propagating and dormant surface polymer chain ends.

[0205] Interestingly, like the solvent composition, the catalyst / ligand complex concentration (composition) is a useful and readily accessible tool for pre-determining the average dry film thickness. The inventors recognize that despite the high complexity of the effect of catalyst / ligand complex concentration, and manipulation thereof is an effective tool to achieve surface polymers with average dry film thicknesses below 50 nm or above 50 nm.

[0206] In this example, the inventors observe that the average dry film thickness reaches a plateau, most pronounced for Reaction condition ID 6.2 and 6.3. these plateaus are useful in reaching a predetermined average dry film thickness within a broad process window - i.e. for Reaction condition 6.2 and 6.3 an operator could remove a substrate at polymerization time 20 minutes and get an average dry film thickness of 49 - 51 nm, while removing a substrate at polymerization time 40 minutes would yield an average dry7film thickness of 53-54 nm, an increase of 3-4 nm, or 6% to 8% over a 20 minute period. This provides a major advantage from a manufacturing perspective as it allows a high degree of flexibility in the process flow.

[0207] Example 7

[0208] Dampening effect of solvents with varying dielectric constants on surface polymer formation

[0209] In this experiment the inventors investigated the influence of Solvent 1 dielectric constants (dielectric constants MeOH > EtOH > iPrOH) and compared these with a solvent selected from DMSO and 1,4-di oxane (dielectric constant DMSO > 1,4-dioxane), where the dielectric constant of DMSO is higher than MeOH and the dielectric constant of 1,4-dioxane is higher than iPrOH. The impact thereof on the average dry film thickness of formed surface polymers was investigated.

[0210] In a glass container (Container C), Catalyst T was prepared by dissolving CuCk 2H2O (13.64 mg) and TPMA (84.21 mg) in Solvent 2 (Dl-water) (9 mL) and Solvent 1 (7 mL) as defined in Table 6. To a glass container (Container A) was added Catalyst T (16 mL), Dl-water (Solvent 2, 519 mL) and Solvent 1 (375 mL) as indicated in Table 6. The solution was sonicated for 5 minutes.

[0211] In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes. Then. GMA monomer (75 mL) was added to Container A.

[0212] For each reaction IDs, 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS), pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2 or Example 3 were placed in the reaction container, and one substrate was withdrawn at a certain time, according to Table 7. to conduct a surface polymer formation rate experiment as described in Example 4. Below, the average dry film thickness of the formed surface polymers obtained at each time, for each solvent, is reported in Table 7.

[0213] Table 6. Solvent 1 and Solvent 2 used in Container A and Container C.

[0214] *: From https: / / people.chem.umass.edu / xray / solvent.html

[0215] Table 7: Polymerization times and corresponding average dry film thickness and thickness standard deviation of surface polymers obtained from rate experiments in Example 6, from reaction compositions comprising Dl-water as Solvent 2 and one other organic solvent as Solvent 1, as indicated in the first column. In Fig. 12, average dry film thickness as a function of polymerization time for reaction compositions comprising DI water and one of methanol, ethanol, or isopropanol is shown.

[0216] Surprisingly, as can be seen in Fig. 12, the inventors discovered that the dielectric constant of Solvent 1 affects the overall average dry film thickness of the formed surface polymers: using a Solvent 1 with increasing dielectric constant, polymerization activity (rate) increased resulting in a higher average dry film thickness. Especially when Solvent 1 is a solvent with an alcohol functional group, the inventors recognized a relation between the dielectric constant of the solvent, namely MeOH, EtOH, and iPrOH, and the average dry film thickness, as can be seen in Fig. 13. In Fig. 13 the average dry film thickness after 20 minutes polymerization time for reaction ID 7.1, 7.2. and 7.3 as indicated in Table 7, plotted against the dielectric constant of the co-solvent.

[0217] Quite surprisingly, as can be seen in Table 7, the trend was not clearly observed when Solvent 1 is an aprotic solvent having no alcohol functional group, DMSO or 1,4-dioxane. For the alcohols MeOH. EtOH and iPrOH, a lower dielectric constant resulted in a lower average dry film thickness (in case of same polymerization conditions), whereas this is not the case for 1.4-dioxane and DMSO, the use of 1,4-dioxane as Solvent 1 leads to a similar average dry film thickness as when using EtOH as Solvent 1, despite the dielectric constant of EtOH being more than ten times that of 1,4-dioxane. The inventors speculate that this difference is due to the protic nature of the alcohols versus the aprotic nature of DMSO and 1,4-dioxane. however, considering that the reaction composition comprises a mixture of water as Solvent 2 and either protic or aprotic Solvent 1 in all cases, the reaction composition is of an overall protic nature. Hence, finding that the activity of the polymer forming liquid (hence the average dry' film thickness) correlates with the dielectric constant of a protic Solvent 1 is strongly unexpected considering the overall nature of reaction compositions investigated.

[0218] Example 8

[0219] Dampening effect of solvents in relation to ligands used for surface polymerization

[0220] In this example, the impact of the composition of the solvent on the average dry film thickness was investigated in case of tBMA monomer and PMDETA ligand forming a catalyst / ligand complex Cu / PMDETA, to corroborate that the discovered influence of the ratio of Dl-water to solvent having an alcohol functional group on the average dry film thickness is a more general trend. For Reaction ID 8.1 : In a glass container (Container A) was added Catalyst P (16 mL), Solvent 2 (Dl-water) and Solvent 1 (iPrOH) in varying volume as defined in Table 8. tBMA monomer (75 mL) was added. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL DL water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes.

[0221] For Reaction ID 8.2 and 8.3: To a glass container (Container A) was added Catalyst P (16 mL), Dl-water (Solvent 2) and iPrOH (Solvent 1) in varying volume as defined in Table 8. The solution was sonicated for 1 minute to remove air bubbles. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes. Then tBMA monomer (75 mL) was added to Container A.

[0222] For each Reaction ID, 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS), precleaned as described in Example 1 and subjected to initiator-modification as described in Example 2 were placed in the reaction container, and one substrate was withdrawn at a certain time, according to Table 9, to conduct a surface polymer formation rate experiment as described in Example 4. Below, the average dry film thickness of obtained surface polymers at each time, for each type of solvent, is reported in Table 9. The data sets from each Reaction ID are reported with an R2value, this value is the coefficient of determination obtained by fitting the data set to a linear regression.

[0223] Table 8. Specific volumes of Solvent 1 and Solvent 2 in Container A used for Reaction ID 8.1- 8.3. Table 9. Polymerization time and corresponding an average dry film thickness and thickness standard deviation of surface polymers obtained in Solvent 1 (iPrOH). R2values based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to the 1.7 nm of the CPTMS initiator layer. TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes and 40 minutes, used to evaluate plateau.

[0224] The findings are shown in Fig. 14 (plot of an average dry film thickness as a function of polymerization time for 3 different reactions comprising different ratios of Dl-water and isopropanol). The results observed from Fig. 14, Fig. 10 (see previously), and Fig. 11 (see previously), suggest that changing the ligand type in the catalyst / ligand complex from TPMA to

[0225] PMDETA leads to an altered rate profile of the surface polymerization. In case of PMDETA, the rate is linear (Fig. 5. R2> 0.95. Table 9). which is expected due to the nature of the PMDETA ligand and indicates a living / controlled polymerization, whereas TPMA rate profile is more akin to that of a linear polymerization with rapid thickness growth that tapers off with time and may approach an average dry film thickness plateau with increasing polymerization time. In Example 5, TMIN / TMAX > 0.80 in all cases as a plateau could be reached, whereas in this example TMIN / TMAX is < 0.80 as there is full linearity, i.e., no plateau has been reached. Even with a different rate (i.e., the surface polymerization activity), the Vol% of iPrOH in the reaction composition surprisingly modulates the average dry film thickness of the formed surface polymer. However, in this example no plateau was observed within the overall polymerization time. The Vol% of iPrOH modulated the average dry film thickness by changing the slope of the rate profile, i.e. changing the rate of surface polymer propagation. A higher Vol% of iPrOH (Solvent 1) leads to decreased an average dry film thickness, as also observed for the GMA / TPMA / EtOH (Solvent 1 = EtOH) reaction composition in Example 5. Thus, the trend observed in Example 5 was confirmed and it may surprisingly be concluded that the trend appears to be of a general nature for various solvents having an alcohol functional group (as exemplified by MeOH, EtOH, and iPrOH), even when monomers with different polarities are used (GMA being more hydrophilic than tBMA due to the large, hydrophobic / e / 7-butyl group).

[0226] Example 9

[0227] Dampening effect of solvents in relation to ligand used

[0228] In this example the inventors explored the surface polymer formation under the conditions described in Example 8, now with MeeTREN as ligand in the catalyst / ligand complex. The used monomer was tBMA as in Example 8. The MeeTREN ligand is known to provide a higher surface polymerization rate than PMDETA. This experiment was conducted to investigate whether the observed influence of solvent composition on an average dry film thickness also applies when using a highly active ligand to form the catalyst / ligand complex.

[0229] In a glass container (Container A) was added Catalyst M (31.2 mL), Solvent 2 (Dl-water) and Solvent 1 (iPrOH) in varying volume as defined in Table 10. The tBMA monomer (75 mL) was added. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition (total volume = 1016.2 mL) was left for 5 minutes to activate the catalyst / ligand for surface polymer formation. For each reaction ID, 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS) were pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2. The content of Container A prepared above was poured into the reaction container and used to conduct a rate experiment as described in Example 4. Below, the average dry film thicknesses of obtained surface polymers are reported in Table 11 below.

[0230] Table 10. Specific volumes of Solvent 1 and Solvent 2 in Container A used for Reaction ID 9.1-

[0231] 9.4.

[0232] Table 11: Polymerization time, average dry film thickness of obtained surface polymers, and thickness standard deviation from polymerization rate experiments. TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes and 40 minutes, used to evaluate plateau. Fig. 15 shows a plot of an average dry film thickness as a function of polymerization time for the reaction conditions indicated in Table 11.

[0233] The results obtained are shown in Fig. 15. Changing the ligand from PMDETA (Example 8, Fig. 14) to MeeTREN (this example, Fig. 15) had an impact on the polymerization rate overall profile of the surface polymer formation. The MeeTREN ligand generally exhibits higher polymerization activity followed by termination of the chain growth (for all Experiments, TMIN / TMAX > 0.8). However, the Vol% of the alcohol (here iPrOH) surprisingly modulates the average dry film thickness, but in this case the modulation also leads to different average dry film thickness at the polymerization plateau in case of different Vol% iPrOH, specifically, a higher Vol% of iPrOH led to a plateau having lower average dry film thickness. The establishment of a polymerization plateau region is a very important finding, since it gives a very broad process window, enabling slow and careful handling of, e.g., larger substrates without introducing unintended changes in the average dry film thickness, as well as it makes the process robust and tolerant towards process mishaps, e.g., when substrates are left in reaction containers for longer times due to some unforeseen events, e.g., mechanical breakdown of handling equipment. As such, the methods disclosed herein are highly suited for large scale manufacturing and industrial processes due to the broad process windows. Also, it was noted from Table 11 that the standard deviation is very7low, thus, implying a homogeneous nature of the formed surface polymer across the substrate.

[0234] Thus, the trend observed in the previous example was confirmed, i.e. higher Vol% alcohol used led to decreased an average dry film thickness. The fact that Vol% alcohol present in the solvent modulates the average dry film thickness across 3 different ligands with significantly different reactivities (PMDETA, TPMA, and MeeTREN, order of increasing polymerization activity), 2 different monomers (GMA and tBMA), and three types of alcohols (MeOH, EtOH, iPrOH) was highly unexpected and an important finding which may be used to modulate the specific average dry film thickness of resulting formed surface polymers. Nonetheless, these parameters make for useful and readily accessible tools for pre-determining an average dry film thickness.

[0235] Example 10

[0236] Combined effect of lower catalyst / ligand complex concentration with fixed solvent composition In this example the inventors re-investigate the effect of the catalyst / ligand complex loading for the reaction composition investigated in Example 9 (tBMA as monomer), where the inventors explored the effect of a highly active catalyst / ligand complex (the MeeTREN ligand) in combination with a solvent composition with a highly dampening effect on an average dry film thickness (low dielectric constant, iPrOH). In this example, the catalyst concentration was decreased by adding less of the aqueous Catalyst M. To ensure a stable Vol% of Solvent 1, the amount of Solvent 2 was adjusted to a certain volume.

[0237] In a glass container (Container A) was added Catalyst M and Solvent 2 (Dl-water) in amounts corresponding to the values in the Table 12, and Solvent 1 (iPrOH, 537 mL), and tBMA monomer (75 mL). In a separate container (Container B) a solution ofNaAsc (4000 mg in 15 mL DI- water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes.

[0238] For each reaction ID, 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS) were, pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2. The content of Container A prepared above was poured into the reaction container and used to conduct a rate experiment as described in Example 4. Below, the average dry film thicknesses of obtained surface polymers are reported in Table 12. The data sets from each Reaction ID are reported with an R2value, this value is the coefficient of determination obtained by fitting the data set to a linear regression.

[0239] Table 12. Components of the reaction composition investigated in this example, including amount of catalyst M and Solvent 2 (Dl-water), and the derived concentration of Cu of the catalyst / ligand complex (Catalyst M). and concentration of ligand in the catalyst / ligand complex (Me6TREN ligand). Note: Reaction ID 10. 1 is the same as Reaction ID 9. 1, Example 9. Table 13. Polymerization time, average dry film thickness of obtained surface polymers, and thickness standard deviation from reaction ID 10.1, 10.2, and 10.3. R2 values based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to the 1.7 nm of the CPTMS initiator layer. TMIN / TMAX is the ratio between the average dry film thickness at 20 minutes and 40 minutes, respectively, used to evaluate plateau. Here, TMIN and TMAX are the lowest respectively the highest of the average dry film thicknesses measured at 20 minutes and 40 minutes. Note: Reaction ID 10.1 is the same as Reaction ID 9.1, Example 9.

[0240] Fig. 16 shows a plot of an average dry film thickness as a function of time, for the reaction compositions indicated in Table 12 and in the example description. Surprisingly, the inventors found that by lowering the catalyst concentration, the overall polymerization activity trend changes towards a linear rate t. R2increases going from ID 10. 1 over 10.2 to 10.3. For ID 10.3, R2> 0.95 here defined as linear rate. In Example 6, the inventors found that lowering the catalyst concentration, the polymerization activity increased but the overall rate remained. The inventors hypothesize that the combination of a Solvent 1 with a dampening effect (iPrOH) and a highly active ligand may be the reason for these observations. As the catalyst concentration is lowered the activity was expected to increase (see Example 6), however, as Solvent 1 has a dampening effect, the sensitive equilibrium between active and dormant catalyst species is managed and a more living (linear) nature is obtained for the polymerization. An increasingly living rate is indicative from the more linear rate profile. This is indeed surprising as the previous examples have shown that the effect of Solvent 1 is predominantly dampening, however, with this example the inventors hypothesize that in certain combinations of Solvent 1 and catalyst / ligand complex, the rate profile of the polymerization activity may be modulated as well.

[0241] Overall, when comparing with the findings of Examples 5-10, modulating the alcohol (Solvent 1) content of the solvent, the choice of ligand and concentration catalyst / ligand complex for surface polymerization offers an unexpected and unique possibility of forming surface polymers with a specific pre-determined average dry film thickness. This unexpected finding provides a valuable tool in the specific design of surface polymers for various uses and purposes.

[0242] Example 11 tBMA (monomer) concentration variations in DI-water / iPrOH (Solvent 2 / Solvent 1) and Me6TREN ligand

[0243] In this example the inventors investigated the influence of varying the monomer concentration of the reaction composition using the reaction composition described in Example 10. Expectedly, the overall polymerization activity will be lowered at lower monomer concentrations, due to lower availability of monomer for surface polymer formation.

[0244] In a glass container (Container A) was added Catalyst M (31.2 mL) and Solvent 2 (Dl-water), Solvent 1 (iPrOH, 53 Vol%), and tBMA monomer in amounts described in Table 14. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes.

[0245] 6 CPTMS-initiator-modified substrates (substrate Si, initiator CPTMS), pre-cleaned as described in Example 1 and subjected to initiator-modification as described in Example 2 were applied. The content of Container A prepared above was poured into the reaction container and a polymerization rate experiment as described in Example 4 was conducted. Below, the average dry film thicknesses of obtained surface polymers are reported in Table 15. Table 14. Reaction compositions for Reaction ID 11.1 and 11.2 composing of Dl-water (Solvent 2), iPrOH (Solvent 1), and monomer volumes and monomer volume percentage. Catalyst M as in Example 10. Results of reaction ID 11.1 is obtained in Example 9, Reaction ID 9.1 .

[0246] Table 15. An average dry film thickness and standard deviation at the indicated polymerization times, for the conditions given in Table 14 and in the example description. Reaction ID 11.1 is results obtained in Example 9 Reaction ID 9.1. Expectedly, by investigating 2 reactions with different monomer concentrations and otherwise similar reaction composition, lowering the monomer concentration results in a lower reaction activity (Fig. 17). Fig. 17 shows the average dry film thickness of the substrates with IDs 11.1 and 11.2. In fact, by halving the monomer concentration the obtained average dry film thicknesses are nearly halved as well. Deviation to this trend is hypothesized to be due to slight changes to the overall reaction composition polarity as the contribution of the monomer to reaction composition polarity is lowered as the monomer concentration is lowered. Hence, the monomer concentration can be used to modulate the overall average dry film thickness of the surface polymer. Lowering the monomer concentration will also lower the rate of the polymerization and vice versa. Example 12

[0247] Dampening effect of solvents in relation to monomer

[0248] In this example, the inventors explored the surface polymer formation under the conditions described in Example 5, now with MMA as monomer. MMA and GMA are both methacrylate monomers of comparable reactivity', but with different solubilities in aqueous media. The epoxide group on GMA makes it a more hydrophilic methacrylate monomer than MMA. This experiment was conducted to investigate whether the observed influence of solvent composition on an average dry film thickness also applies when using the less hydrophilic methacrylate monomer.

[0249] Silicon wafer substrates (r = 5.08 cm, cut to l / 4thof a wafer, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm. (100), p-type (Boron), purchased from MicroChemicals GmbH) were cleaned and initiator-modified using the following method:

[0250] Racks containing the substrates were placed in iPrOH and sonicated for 5 minutes in a big sonicator. Then, the substrates mounted in the racks were placed in an oven at 80°C for 15 minutes. Thereafter, the racks containing the substrates were transferred to a 5: 1 : 1 DI-water / NH4OH / H2O2 solution at temperatures between 70°C and 75°C and sonicated for 10 minutes. Next, the substrates were flushed under a running tap of Dl-water and transferred to a Dl-water container and sonicated for 5 minutes. Thereafter, the substrates were transferred to an iPrOH container and sonicated for 5 minutes, before being dried in an oven at 80°C for 15 minutes. Finally, the substrates were subjected to initiator-modification as described in Example 3.

[0251] In a glass container (Container C), Catalyst T was prepared by dissolving CuCL 2H2O (13.64 mg) and TPMA (84.21 mg) in Solvent 1 (EtOH, 7 mL) and Solvent 2 (Dl-water, 9 mL).

[0252] To a glass container (Container A) was added Catalyst T (16 mL), Solvent 2 (Dl-water), Solvent 1 (EtOH) and MMA monomer (75 mL) in varying volumes as defined in Table 16. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes. The content of Container A was poured into a reaction container.

[0253] For each reaction ID, 6 CPTMS-initiator-modified substrates (substrate Si: pre-cleaned as described above, initiator CPTMS: as described in Example 3) were applied. The content of Container A prepared above was poured into the reaction container and used to conduct a rate experiment as described in Example 4. The average dry film thicknesses of obtained surface polymers are reported in Table 17. Table 16: Specific volume of Dl-water and EtOH in Container A for Reaction ID 12.1-12.5.

[0254] Table 17: Polymerization time, average dry film thickness of obtained surface polymers, and thickness standard deviation from polymerization rate experiments of ID 12.1-12.5.

[0255] The obtained results are shown in Fig. 18 with the average dry film thickness as a function of polymerization time for different solvent ratios as described in Table 16 for ID 12.1-12.5. The components (ligand, activator, catalyst, monomer) are identical in ID 12.1-12.5, thus the differences in dry film thicknesses are only related to changes in Solvent 1 (EtOH) content. As observed in Fig. 18, the overall polymerization activity' is significantly lowered with an increasing volume percentage of EtOH. The rate profile during the polymerization time remained similar regardless of EtOH content.

[0256] Interestingly, increasing Solvent 1 (EtOH) content from 42% to 45%, a 3-percentage point change, leads to an approximately 25% lower an average dry film thickness after a polymerization time of 20 minutes. Moreover, increasing the Solvent 1 (EtOH) content from 42% to 75%. a 33-percentage change, leads to an approximately 84% lower average dry film thickness after a polymerization time of 20 minutes. Surprisingly, the impact of increasing EtOH content is decreased towards higher EtOH content. This tendency is shown in Fig. 19 with the average dry film thickness after 20 minutes as a function of EtOH Vol% as described in Table 16 for ID 12. 1-12.5. As observed in Fig. 19, the relation between average dry film thickness and EtOH content is steeper below 50 Vol% EtOH content, before dampening off towards higher EtOH content. The inventors recognize the high complexity' of the effect of the solvent composition; thus, the two different regimes may be related to solubilities of catalyst, monomer, and the surface bound polymer film.

[0257] The effect of solvent composition on obtained average dry' film thickness was also observed in Example 5 with GMA monomer. This indicates that the DI-w aler / EtOH solvent composition has a major impact on the polymerization rate regardless of methacry late monomer polarity and can be used to modulate the specific average dry film thickness of resulting formed surface polymers.

[0258] Example 13

[0259] MMA (monomer) concentration variations in DI-water / EtOH and TPMA ligand and batch-to- batch variation

[0260] In this example the inventors investigated the influence of varying the relative amount of monomer (concentration) of the reaction composition. In this example, the inventors maintained the same volume (combined volume of Solvent 1, Solvent 2, monomer) in the different Reaction IDs by replacing monomer volume with ahigher Solvent 2 (Dl-water) volume (IDs 13.2, 13.3 and 13.4). Increased water concentration was, in above examples, shown to have an accelerating effect on the rate of surface polymerization. This example shows that the change in amounts of Solvent 1 and Solvent 2 in combination with changing the amount of monomer relative to the total volume of reaction composition influences the average dry film thickness of the formed surface polymers.

[0261] Silicon wafer substrates (r = 5.08 cm, cut to l / 4thof a wafer, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm. (100), p-type (Boron), purchased from MicroChemicals GmbH) were cleaned and initiator-modified using the following method:

[0262] Racks containing the substrates were placed in iPrOH and sonicated for 5 minutes in a big sonicator. Then, the substrates mounted in the racks were placed in an oven at 80°C for 15 minutes. Thereafter, the racks containing the substrates were transferred to a 5: 1 : 1 DI-water / NH4OH / H2O2 solution at temperatures between 70°C and 75°C and sonicated for 10 minutes. Next, the substrates were flushed under a running tap of Dl-water and transferred to a Dl-water container and sonicated for 5 minutes. Thereafter, the substrates were transferred to an iPrOH container and sonicated for 5 minutes, before being dried in an oven at 80°C for 15 minutes. Finally, the substrates were subjected to initiator-modification as described in Example 3.

[0263] In a glass container (Container C), Catalyst T was prepared by dissolving CuCh 2H2O (13.64 mg) and TPMA (84.21 mg) in Solvent 1 (EtOH, 7 mL) and Solvent 2 (Dl-water, 9 mL).

[0264] To a glass container (Container A) was added Catalyst T (16 mL), Solvent 2 (Dl-water), Solvent 1 (EtOH) and MMA monomer in varying volumes as defined in Table 18. In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes. The content of Container A was poured into a reaction container.

[0265] For each reaction ID, 6 CPTMS-initiator-modified substrates were applied. The content of Container A prepared above was poured into the reaction container and used to conduct a rate experiment as described in Example 4. The average dry film thicknesses of obtained surface polymers are reported in Table 18 and 19.

[0266] Table 18. Reaction compositions for Reaction ID 13.1-13.4 comprising Dl-water (Solvent 2), EtOH (Solvent 1), and monomer volumes and monomer volume percentages. Results of reaction ID 13.1 is obtained in Example 12, Reaction ID 12.5. Note: ID 13.3 and 13.4 are replicas of ID 13.2.

[0267] Table 19. An average dry film thickness and standard deviation at the indicated polymerization times, for the conditions given in Table 18 and in the example description. Reaction ID 13.1 is results obtained in Example 12 Reaction ID 12.5. Note: ID 13.3 and 13.4 are replicas of ID 13.2. The obtained results are shown in Fig. 20 with the average dry film thickness as a function of polymerization time for ID 13.1-13.4. As observed in Example 11 , the thicknesses appear to be related to the monomer concentration, thus, demonstrating monomer concentration as a useful and simple way of modulating the obtained an average dry film thickness in addition to the solvent composition.

[0268] Importantly, replicas 13.2-13.4 give similar results, demonstrating that the reaction compositions and methods as described herein are robust and reliably lead to the formation of very thin surface polymers with pre-defined average dry film thicknesses. The obtained results demonstrate the robustness of the devised methodology of varying the solvent composition and amount of monomer relative to the total volume of the reaction composition to modulate formation of surface polymers to obtain surface polymers with a very' low average dry' film thickness (thin surface polymer) with a pre-defined targeted average dry film thickness and very low variation across polymerization and substrates. Thus, average dry' film thickness can be modulated by changing the amount of second solvent (Solvent 2) and the amount of monomer relative to the total volume of the reaction composition.

[0269] Example 14

[0270] Surface polymerization on larger substrate applying surface polymer conditions of Example 13, Using the surface polymerization conditions described in Example 13 (ID 13.2-13.4) which demonstrated very low batch-to-batch variations in the formed thin surface polymers, the inventors tested whether the surface polymerization conditions could be used to form surface polymers on a larger substrate, namely a silicon wafer with a 7.62 cm radius, with high conformality i.e., very low on-sample variation of the an average dry' film thickness.

[0271] A silicon wafer substrate (Prime CZ-Si wafer, 6-inch, thickness = 675 ± 25 pm, (100), 2-side polished, p-type (Boron), purchased from MicroChemicals GmbH) was cleaned and initiator- modified using the following method:

[0272] A rack containing the substrate was placed in iPrOH and sonicated for 5 minutes in a big sonicator. Then, the substrate mounted in the rack was placed in an oven at 80°C for 15 minutes. Thereafter, the rack containing the substrate was transferred to a 5: 1: 1 DI-water / NH4OH / H2Ch solution at temperatures between 70°C and 75°C and sonicated for 10 minutes. Next, the substrate was flushed under a running tap of Dl-water and transferred to a Dl-water container and sonicated for 5 minutes. Thereafter, the substrate was transferred to an iPrOH container and sonicated for 5 minutes before being dried in an oven at 80°C for 15 minutes. Finally, the substrate was subjected to initiator-modification as described in Example 3.

[0273] In a glass container (Container C), Catalyst T was prepared by dissolving CuCL 2H2O (47.73 mg) and TPMA (294.73 mg) in Solvent 1 (EtOH, 24.5 mL) and Solvent 2 (Dl-water, 31.5 mL).

[0274] To a glass container (Container A) was added Catalyst T (56 mL), Solvent 2 (Dl-water, 656.25 mL), Solvent 1 (EtOH, 2604 mL) and MMA monomer (131.25 mL).

[0275] In a separate container (Container B) a solution of NaAsc (14000 mg in 52.5 mL Dl-water) was prepared. The content of Container B was poured into Container A and the reaction composition was left for 5 minutes. The content of Container A was poured into a reaction container.

[0276] The rack containing the CPTMS-initiator-modified substrate (substrate Si, initiator CPTMS) was transferred to the reaction container and withdrawn after 10 min. The substrate was flushed with Dl-water and sonicated in Dl-water for 5 minutes in a big sonicator. The substrate was flushed with acetone, then sonicated in acetone for 5 minutes in a big sonicator before being dried in an oven at 80°C for 2 minutes. The next day the sample was sonicated in acetone for 5 minutes in a big sonicator, then flushed with iPrOH, then sonicated in iPrOH for 5 minutes in a big sonicator. Finally, the sample was dried in an oven at 80°C for 5 minutes. Below, the average dry film thickness of the formed surface polymers obtained is reported in Table 20.

[0277] Table 20. An average dry film thickness, standard deviation, and coefficient of variation (CV) for 6-inch coated silicon wafer.

[0278] Notably, the process used in this example can form very thin surface polymers with a CV of 2.5% on a large substrate. This result illustrates how the methods disclosed herein are compatible with high volume manufacturing conditions where larger substrates are coated with thin, well-defined, dry surface polymers. These findings further confirm the robustness of the methods disclosed herein and the valuable modulation of surface polymer formation rates. Furthermore, the very’ low batch-to-batch variation observed in Example 13 could be directly transferred to a much larger substrates, still leading to the targeted average dry film thickness of formed surface polymers.

[0279] Example 15

[0280] Effect of ligand ty pe on PMMA surface polymer formation

[0281] In this example, the polymerization rate profile of different ligands (MeeTREN, TPMA and PMDETA, respectively) was investigated in case of a surface polymerization with MMA monomer. The complex formed between Cu and the ligand in question and its activity is influenced on, i.a., the solubility, the geometry of the formed Cu / ligand complex and the electron-donating ability of the ligand to the copper ion. In this experiment, only the ligand type was changed (i.e., other components of the reaction composition were the same).

[0282] Silicon wafer substrates (r = 5.08 cm, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), purchased from MicroChemicals GmbH) were polymerization initiator-modified as described in Example 3. The day following the polymerization initiator-modification, the substrates were cut to 1 / 4* of a wafer.

[0283] In separate glass containers (3 Container Cs), the various catalysts (Cu / ligand complex) (denoted Catalyst M.15 (MeeTREN), Catalyst T.15 (TPMA) and Catalyst P.15 (PMDETA)) were prepared by dissolving the ligand in Solvent 1 (EtOH, 7 mL) and 9 mM CuCh-2H2O (9 mL). The amount of each ligand is shown in Table 21 .

[0284] Table 21. Amount and type of catalyst / ligand. Catalyst was Cu.

[0285] To a glass container (3 Container As) was added Catalyst M.15, Catalyst T.15 or Catalyst P.15, Solvent 2 (Dl-water), Solvent 1 (EtOH) and MMA monomer as shown in Table 22.

[0286] Table 22. Components of reaction compositions for Reaction ID 15.1-15.3 used for surface polymerization before activation of reaction composition.

[0287] In a separate container (3 Container Bs), a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and each of the reaction compositions was left for 5 minutes to activate the reaction compositions for surface polymer formation.

[0288] For each reaction ID, 6 CPTMS-initiator-modified substrates were used for surface polymerization. The content of each Container A was poured into a reaction container (one for each reaction composition) and a polymerization rate experiment was performed as described in Example 4. The average dry film thicknesses of obtained surface polymers are shown in Table 23 together with the linear regression fitting values.

[0289] Table 23. Polymerization conditions for each Reaction ID and average dry film thicknesses of obtained surface polymers determined by ellipsometry. R2values are based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to 1.7 nm thickness of CPTMS initiator layer. TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes (MIN) and 40 minutes (MAX), respectively, used to evaluate if a plateau has been reached.

[0290] The results are shown in Fig. 21 with the average dry film thickness as a function (y-axis) of polymerization time (x-axis) for Reaction ID 15.1-15.3.

[0291] The results show a unique polymerization rate for each of the different ligands. Interestingly, ligands MeeTREN and TPMA caused a more rapid polymerization rate initially, decreasing towards the end of the polymerization rate experiment, whereas ligand PMDETA caused a more slow surface polymer propagation, appearing with a linear polymerization rate profile. The inventors believe the observed polymerization rate profile to be related to the geometry of the catalyst (MeeTREN and TPMA being tetradentate ligands with four coordination sites on the copper ion, whereas PMDETA is a tridentate ligand with three coordination sites on the copper ion). The difference in denticity of the ligands (coordination sites and geometry) may indeed result in the observed different polymerization rate profiles. This may be used to further modulate the polymerization rate in combination with the solvent composition (Vol% of Solvent 1 and Solvent2) to control the rate of polymerization and average dry film thickness of surface polymers. It is noted that the TMIN / TMAX values for MeeTREN and TPMA are 0.86 and 0.87, respectively, indicating that an average dry' film thickness plateau will soon be reached, whereas PMDETA has a TMIN / TMAX of 0.37 indicating that the polymerization will proceed for a longer polymerization time before its polymerization plateau is reached. This observation may be used to target a certain polymerization time to reach polymerization plateau, aiding in designing optimal process conditions for manufacturing. For large-scale manufacturing, reaching the polymerization plateau may be beneficial, since it provides more flexibility as regards operation time of surface polymerization with low batch-to-batch variation. Furthermore, a slower but more living polymerization (e.g., with ligand PMDETA) may also be desirable for some surface polymer formations, e.g., block-polymer formation, thus emphasizing the advantages in modulating the rate of polymerization to obtain a desired polymerization rate and polymerization profile.

[0292] Example 16

[0293] Effect of ligand type on GMA surface polymerization

[0294] The surface polymer formation using the same ligands as in Example 15, but with GMA as monomer, was investigated. MMA and GMA monomers are both methacrylate monomers of comparable reactivity, but with different solubilities in aqueous media. The epoxide group on the GMA monomer makes it more hydrophilic than the MMA monomer. This experiment was conducted to investigate whether the observed influence of ligand type on polymerization rate and an average dry film thickness also applies when using a more hydrophilic methacrylate monomer.

[0295] Silicon wafer substrates (r = 5.08 cm, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), purchased from MicroChemicals GmbH) were polymerization initiator-modified as described in Example 3. The day following the initiator-modification the substrates were cut to 1 / 4* of a wafer. In separate glass containers (3 Container Cs), the various catalysts (Cu / ligand complex) (denoted Catalyst M.16 (MeeTREN), Catalyst T.16 (TPMA) and Catalyst P.16 (PMDETA)) were prepared by dissolving the ligand in Solvent 1 (EtOH, 7 mL) and 9 mM CuCh 2H2O aq. (9 mL). The amount of each ligand is shown in Table 24.

[0296] Table 24. Amount and type of catalyst / ligand. Catalyst in the catalyst / ligand complex was Cu.

[0297] To a glass container (3 Container As) was added Catalyst M.16, Catalyst T.16 or Catalyst P.16, Solvent 2 (Dl-water), Solvent 1 (EtOH) and GMA monomer as shown in Table 25.

[0298] Table 25. Components of reaction compositions for Reaction ID 16.1-16.3 used for surface polymerization before activation of reaction composition.

[0299] In a separate container (3 Container Bs), a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A and each of the reaction compositions was left for 5 minutes to activate the reaction compositions for surface polymer formation.

[0300] For each Reaction ID, 6 CPTMS-initiator-modified substrates were used for surface polymerization. The content of each Container A was poured into a reaction container (one for each reaction composition) and a polymerization rate experiment was performed as described in Example 4. The average dry film thicknesses of obtained surface polymers are shown in Table 26 together with the linear regression fitting values. Table 26. Polymerization conditions for each Reaction ID and average dry film thicknesses of obtained surface polymers determined by ellipsometry. R2values are based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to 1.7 nm thickness of CPTMS initiator layer. TMIN / TMAX is the ratio between the average dry film thickness after 20 minutes (MIN) and 40 minutes (MAX), respectively, used to evaluate if a plateau has been reached.

[0301] The obtained results are shown in Fig. 22 with the average dry film thickness as a function of polymerization time for different ligands as described in Table 25 for Reaction ID 16.1-16.3. As observed in Fig. 22, the ligands show different polymerization rates. MeeTREN and TPMA polymerize rapidly initially but exhibit a decrease in polymerization rate towards the end of the polymerization rate experiment, whereas ligand PMDETA appears to have a slower and more linear polymerization rate. Correspondingly, the TMIN / TMAX values of Me6TREN and TPMA are 0.76 and 0.91 respectively indicating that an average dry film thickness plateau is soon reached, while PMDETA has a TMIN / TMAX of 0.64 indicating that the polymerization will proceed for a longer time before a polymerization plateau is reached.

[0302] Interestingly, the same trend was also observed in Example 15 with the MMA monomer. This indicates that the denticity of ligands (tetradentate versus tridentate) and thereby geometry of the catalyst as described in Example 15 also applies to more hydrophilic monomers and solvent compositions, amplifying the significant polymerization rate modulation obtained by ligand selection. The inventors conclude that ligand selection may be made based on, e,g., solubility of the ligand and / or monomer, and may provide advanced control in terms of both polymerization rate and obtained average dry film thickness of the surface polymers.

[0303] Example 17

[0304] Dampening effect of solvents with varying dielectric constants on surface polymer formation of vinvl monomer

[0305] In this experiment the influence of Solvent 1 dielectric constants (dielectric constants MeOH > EtOH > iPrOH) on the average diy film thickness of surface polymers formed from styrene (a nonmethacrylate monomer) was investigated.

[0306] Silicon wafer substrates (r = 5.08 cm, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), purchased from MicroChemicals GmbH) were initiator-modified according to Example 3. The day following the polymerization initiator-modification, the substrates were cut to l / 4thof a wafer.

[0307] In a glass container (Container C), Catalyst T was prepared by dissolving TPMA (84 mg) in Solvent 1 (7 mL) and 9 mM CuCk 2H2O (aq.) (9 mL) as defined in Table 27.

[0308] To a glass container (Container A) was added Catalyst T (16 mL), Solvent 1 (480 mL), Solvent 2 (Dl-water, 460 mL) and styrene monomer (5 mL) as indicated in Table 27. In a separate container (Container B), a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A. and the reaction composition was left for 5 minutes. For each reaction ID, 4 CPTMS-initiator-modified substrates were used for surface polymerization, and one substrate was withdrawn after a certain polymerization time, according to Table 28, to conduct a surface polymer formation rate experiment as described in Example 4. Below, the average dry film thickness of the formed surface polymers obtained at each time, for each solvent, is reported in Table 28.

[0309] Table 27. Solvent 1 and Solvent 2 used in the experiments.

[0310] *■ From https: / 'people. chem. umass. edwxray / solvent. html

[0311] Table 28: Polymerization times and corresponding average dry film thicknesses determined by ellipsometry and thickness standard deviation of surface polymers.

[0312] In Fig. 23, an average dry film thickness (y-axis) as a function of polymerization time (x-axis) for Reaction IDs 17.1-17.3 is shown. It appeared that the dielectric constant of Solvent 1 markedly influences the obtained average dry film thickness of the obtained surface polymer. Using a Solvent 1 with increasing dielectric constant (see Fig. 13), polymerization activity (thus, polymerization rate) increased resulting in a higher an average dry film thickness. Interestingly, polymerizations in MeOH and EtOH indicated that surface polymer propagation progressed in linear manner with polymerization time, indicating that the profile of the polymerization rate (linear) remained unaffected by the changes in dielectric constant of Solvent 1. The inventors hypothesize that the very thin average dry film thickness observed in case of iPrOH (lowest dielectric constant of MeOH, EtOH and iPrOH) as Solvent 1 is due to the high dampening factor of this solvent (as discussed in Example 10). Thus, this finding may be used to modulate the reaction composition so as to obtain very thin surface polymers. Hence, finding that the polymerization rate profile for surface polymer formation depends on the dielectric constant of a protic Solvent 1 for a styrenic monomer (compared to the previous results shown with methacrylates) underlines the versatility' of the solvent composition as a modulation tool for modulation of surface polymer forming activity, across different monomer types.

[0313] Example 18

[0314] Styrene surface polymerization with MeeTREN ligand

[0315] Silicon wafer substrates (r = 5.08 cm, Test CZ-Si wafer, 4 inch, thickness = 525 ± 25 pm, (100), p-type (Boron), purchased from MicroChemicals GmbH) were polymerization initiator-modified as described in Example 3. The day following the initiator-modification the substrates were cut to 1 / 4* of a wafer.

[0316] In a glass container (Container A) was added Catalyst M (30 mL), Solvent 1 (EtOH. 480 mL), Solvent 2 (Dl-water, 460 mL) and styrene monomer (5 mL). In a separate container (Container B) a solution of NaAsc (4000 mg in 15 mL Dl-water) was prepared. The content of Container B was poured into Container A, and the reaction composition was left for 5 minutes.

[0317] 5 initiator-modified substrates were used for surface polymerization, and one substrate was withdrawn at a certain time, according to Table 29, to conduct a surface polymer formation rate experiment as described in Example 4. Below', the average dry' film thickness of the formed surface polymers obtained at each time is reported.

[0318] Table 29: Polymerization times and corresponding an average dry film thickness determined by ellipsometry' and thickness standard deviation of surface polymers. R2value based on linear regression fit of entire data series, where the fit is set to intercept the y-axis at 1.7, corresponding to the estimated 1.7 nm thickness of the CPTMS initiator layer. TNHN / TMAX is the ratio between the average dry' film thickness at 20 minutes and 40 minutes, respectively, used to evaluate plateau. The obtained results are shown in Fig. 24 with the average dry film thickness (y-axis) as a function of polymerization time (x-axis) for Reaction ID 18.1. As observed in Fig. 24, the polymerization rate was fast initially before slowing down towards the end of the timeframe investigated. The polymerization rate appeared to be non-linear (linear fit R2value was 0.72). The TMIN / TMAX value of 0.94 indicated that the polymerization plateau was reached. Such polymerization profile was previously observed in case of the MeeTREN ligand, see Example 10, Reaction ID 10.1. In this experiment as well as the experiment in Example 10, the polymerization plateau was reached. Thus, it may be concluded that the choice of ligand in combination with catalyst concentration is suited for modulating surface polymers of different types (surface polymers of methacrylate monomers in Example 10 and vinyl monomers such as styrene in this Example).

[0319] In this Example, the monomer volume and solvent (Solvent 1 and Solvent 2) composition of Reaction ID 18.1 resembled that of Reaction ID 17.2 (Example 17) with changes being different ligand, catalyst (Cu) concentration, and thereby a 1.4 Vol% difference in EtOH. Surprisingly, Reaction ID 17.2 appeared linear in polymerization rate while Reaction ID 18. 1 appeared to reach a polymerization plateau. This difference in polymenzation rate profile highlights the importance of ligand choice and catalyst concentration on surface polymer formation. Ligand selection and catalyst concentration is an effective tool for modulating surface polymer thickness and polymerization rate profile since within almost same solvent composition and monomer concentration a linear rate (living polymerization) like Reaction ID 17.2 may be useful for forming, e.g., block surface polymers, while a faster polymerization rate with a polymerization plateau like, e.g., Reaction ID 18.1 reaction composition conditions, may be useful for large scale production and low- batch-to-batch variations.

[0320] Comments on the results obtained in the

[0321] As can be gathered from the Examples, the reaction composition comprising monomer, catalyst and ligand forming a catalyst / ligand complex and solvent (first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom) and a second solvent miscible with first solvent) may be modulated, by formulating the reaction composition with varying amounls / types of first and second solvents as well as other components, to yield thinner or thicker surface polymers (lower average dry film thickness) in a controlled, predictable and reproducible manner by controlling the rate of surface polymer formation. Furthermore, the surface polymer formation may be modulated by amount and / or types of reaction composition components so as to reach a polymerization plateau. The polymerization plateau enables reaching a target surface polymer dry film thickness within a broad process window, thus providing a high degree of manufacturability and compatibility with high volume manufacturing. The observations from the results of the Examples may be summarized as follows:

[0322] Using an increasing amount of first solvent surprisingly leads to a dampening of the overall polymerization rate profile of surface polymer formation, thus, surface polymers form with a decreased polymerization rate, in a predictable fashion.

[0323] The dampening effect on surface polymer formation by the first solvent is increased with a lower dielectric constant of the first solvent.

[0324] A lower amount of monomer (lower concentration) may lower the polymerization rate of the surface polymer formation.

[0325] Choosing the ligand of the catalyst / ligand complex results in a change in the polymerization rate of surface polymer formation. The ligands applied in the Examples (PMDETA, Me6TREN and TPMA, respectively) suggest that choosing a ligand with lower activity or denticity', e.g., PMDETA, promotes a more linear polymerization rate, since a lower activity leads to lower presence of active radicals which leads to a lower degree of surface polymer chain end termination. This effect can be observed from both Example 15 and Example 16, where PMDETA leads to a linear polymerization rate profile while both Me6TREN and TPMA catalyst / ligands lead to plateauing rate profiles, in accordance with TPMA and Me6TREN being tetradentate ligands, while PMDETA is a tridentate ligand, thus the two subsets of ligands (TPMA and Me6TREN compared to PMDETA) have different denticities and expected different coordination geometries with the copper catalyst.

[0326] Formulating the reaction composition to comprise a dampening first solvent in combination with a decreased catalyst / ligand complex concentration, alters the rate of the surface polymer formation from a plateauing trend ('‘flat” curve with increasing polymerization time) to a more living trend (“increasing” curve having continued surface formation with polymerization time) (See Example 10 and Fig. 16).

[0327] Scalable surface polymer formation process with low batch-to-batch variation is possible (See Example 5 and Example 13).

[0328] Surface polymer formation may be optimized to enable long and stable process windows for forming surface polymers with predefined average dry film thicknesses. Specifically, very' thin (low average dry film thickness) surface polymers may be obtained with manufacturability in high volume production. Obtaining very thin surface polymers may be considered a challenge, since the process window for forming, e.g., a 4 nm surface polymer, is usually quite narrow, given the rapid polymerization rates observed in methods with more linear, less dampened polymerizations, see, e.g., Example 5, Reaction ID 5.1, in which an average dry film thicknesses of 21.4 nm in 2 minutes and 102 nm in 20 minutes were seen. To obtain, e.g., a 4 nm thick surface polymer under such reaction conditions, an operator / robotic system would have to remove a substrate after a very' short polymerization time, in a very narrow process window of possibly a few seconds or tens of seconds. Additionally, such short polymerization time leaves too little time to allow relaxation of the reaction composition at the surface interface, with the risk of forming inhomogeneous surface polymers. A longer process window may be desired in case of high-volume manufacturing and handling of substates as the larger process window makes possible more manufacturing options. With the controlled rate of surface polymer formation as disclosed herein, this may indeed be achieved. In terms of reliably forming very thin surface polymers, knowing the polymerization time that leads to the desired average dry film thickness may be a valuable tool.

[0329] It is desirable to develop a relatively long and broad process window in terms of polymerization time and stable polymerization rate, when forming very thin and / or homogenous surface polymers. In Example 9 (Fig. 6), the inventors investigated the more active ligand MeeTREN, which in general tends to lead to more rapid surface polymer propagation with short polymerization times (0-15 minutes). Formulating the reaction composition in a certain way allows the rate of surface polymer formation to reach a polymerization plateau after a certain polymerization time, which again allows for a very broad process windows during which the average dry film thickness does not change significantly, e.g., after an initial faster surface polymer propagation period, see Fig. 7. As the inventors have demonstrated, the Vol% of dampening first solvent (Solvent 1 such as iPrOH) can then be used to determine the average dry' film thickness obtained after the initial faster propagation of surface polymers. Here, polymerization plateaus with different an average dry film thicknesses were obtained after ~15 minutes, with the average dry' film thickness at the plateau being adjustable from 10 nm to 60 nm an average dry film thickness by changing the iPrOH Vol% in the solvent from 53 Vol% to 77 Vol%. After ~15 minutes, the average dry' film thickness remained stable and constant from 20 minutes to at least 40 minutes after which the experiment was ended. However, the inventors speculate that the average dry film thickness de facto remains constant for longer, indicating a potentially stable process window' in which a predetermined an average dry' film thickness may be obtained. Furthermore, most likely the average dry film thickness at the polymerization plateau may be further expanded to both lower and higher average dry film thicknesses by further formulating the reaction composition to comprise higher or lower Vol% of the first solvent.

[0330] Example 11 (Fig. 8) illustrates another means of pre-determining the average dry film thickness at the polymerization plateau, namely the monomer concentration of the reaction composition. In this case, reducing the monomer concentration in the reaction composition leads to a lower average dry film thickness at the polymerization plateau, from more than 60 nm to about 25 nm. The inventors speculate that further reducing the monomer concentration in the reaction composition to, e g. , 1 V ol% may lead to an even lower average dry film thickness at the polymerization plateau. Considering Example 12, the inventors demonstrated excellent control of an average dry film thickness in a predictable fashion where the surface polymer propagates slowly from minute 10 to minute 40. This was accomplished by formulating the reaction composition according to embodiments described herein by modulating the Vol% of dampening first solvent, and modulating the monomer amount (concentration) to a reduced monomer concentration (Example 13). This leads to a reliable and robust process which was utilized in Examples 13 and 14 to show low batch-to-batch an average dry film thickness variations as well as very high conformality and homogeneity of an average dry film thickness across a larger substrate.

[0331] Furthermore, the inventors note that the modulation of the rate profile of surface polymerization through the adjustment of ligand ty pe and catalyst / ligand complex amount (concentration) appears to be ubiquitous across different monomer types, as evidenced by the results obtained for a styrenic monomer in Example 17 and Example 18. compared to the findings for methacrylic monomers in Examples 5 to Example 16. These findings indicate that the relation between rate profile and polymerization composition components appear independent of the monomer type, at least for methacrylic and sty renic monomers.

[0332] Comments regarding modulation of the livingness of surface polymer formation

[0333] The inventors observed beneficial properties by formulating the reaction composition so as to yield long and stable process windows by establishing an average dry film thickness plateau to ensure a low batch-to-batch variation (multiple polymerization events for high-volume manufacturing). The inventors were surprised by discovering the complex interplay between solvent (first solvent and second solvent), and catalyst / ligand complex type and amount (concentration) and discovered how these parameters may be used to enable linear polymerization profiles for forming surface polymers with a tunable average dry film thickness. A living surface polymer formation results from a linear rate of surface polymer formation (continuous propagation of surface polymers). The inventors have made it possible to modulate the rate of polymerization towards a more living nature of the surface polymer formation by formulating the reaction composition in a certain manner. A living polymerization rate yields possibilities in producing various an average dry film thicknesses using the same reaction composition for multiple polymerization events, and in building block co-polymer structures as a living procedure generally leaves viable chain-ends on the surface polymer which are available for further polymerization.

[0334] Especially, the inventors hypothesize, the possibility of using the same reaction composition in subsequent / multiple polymerization events to form surface polymers of different average dry film thicknesses, strengthens the application potential of the methods and reaction compositions disclosed herein. In the Examples, the inventors illustrated how the reaction composition comprising monomer, catalyst and ligand forming a catalyst / ligand complex and solvent (first solvent and second solvent) may be formulated with vaiy ing amounts of components present in the reaction composition, to yield a living polymenzation rate.

[0335] Example 8, Fig. 5 shows a linear polymerization rate, which results in predictable an average dry7film thickness that depends on the polymerization time. Such a rate of polymerization was obtained using a less reactive ligand in the catalyst / ligand complex, namely PMDETA. The rate of the polymerization was then modulated on the basis of the inventor’s discovery of the ‘'first solvent”- effect by varying iPrOH (first solvent) Vol% present in the reaction composition, e.g., 53 Vol% iPrOH yielding a steep slope (an average dry film thickness of 7 nm after 10 minutes polymerization time and 19 nm after 40 minutes polymerization time), while 69 Vol% iPrOH led to a much flatter slope (yielding an average dry’ film thickness of 2 nm after 10 minutes polymerization time and 4 nm after 40 minutes polymerization time), leading to a broader process window.

[0336] In Example 10 (Fig. 16). a linear rate of polymerization (i.e. living polymerization) was achieved by modulating an otherwise non-living rate of polymerization. The linear rate of polymerization yvas achieved by loyvering the Cu / MeeTREN complex amount (concentration) (from 165 pm Cu to 41 pm Cu) in combination with a highly dampening first solvent (iPrOH) resulting in surface polymers with average dry film thicknesses of 36 nm after 10 minutes polymerization time and 124 nm after 40 minutes polymerization time. Thus, the rate of the surface polymer formation may be changed from a non-living surface polymer formation to a living surface polymer formation by modulating the amount of the first solvent, the second solvent and the Cu / MeeTREN complex comprised in the reaction composition.

[0337] List of reference numerals

[0338] 100 System

[0339] 102 Substrate

[0340] 103 Substrate displacement device

[0341] 104 Reaction composition container

[0342] 105 Reaction composition

[0343] 106 Container

[0344] 107 Polymerization initiator chemistry

[0345] 109 Annealing oven

[0346] 114 Cleaning container

[0347] 116 Cleaning agent / device

[0348] 118 Roll-to-roll processor

[0349] 120 Roller

[0350] 121 Sending roll

[0351] 122 Receiving roll

[0352] 123 Flexible elongated substrate

Claims

Claims1. A method of controlling a rate of formation of surface polymers on a substrate, the method comprising applying to the substrate a reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of the first solvent and the second solvent are selected to control the rate of surface polymer formation.

2. A method of controlling the rate of formation of surface polymers on the substrate according to claim 1, wherein the relative amounts of and / or types of two or more of: the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation.

3. A method according to claim 1, wherein the relative amount of the first solvent to the amount of the second solvent are selected to control the rate of surface polymer formation.

4. A method according to claim 1, wherein the type of the first solvent, and the relative amount of the first solvent to the amount of the second solvent are selected to control the rate of surface polymer formation.

5. A method according to any one of claims 2-4, wherein the type of monomer is selected to control the rate of surface polymer formation.

6. A method according to any one of claims 2-4, wherein the relative amount of the monomer to the balance of the amount of the reaction composition is selected to control the rate of surface polymer formation.

7. A method according to any one of claims 2-4, wherein the ty pe of the monomer and the relative amount of the monomer to the balance of the amount of the reaction composition is selected to control the rate of surface polymer formation.

8. A method according to any one of claims 2-4, wherein the type of catalyst / ligand complex is selected to control the rate of surface polymer formation.

9. A method according to any one of claims 2-4, wherein the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition is selected to control the rate of surface polymer formation.

10. A method according to any one of claims 2-4, wherein the type of the catalyst / ligand, and the relative amount of the catalyst / ligand complex to the balance of the amount of the reaction composition are selected to control the rate of surface polymer formation.

11. A method according to any one of claims 2-4. wherein the type of the monomer, and the type of the catalyst / ligand complex are selected to control the rate of surface polymer formation.

12. A method according to any one of claims 2-4, wherein the relative amount of the monomer to the balance of the amount of the reaction composition, and the type of the catalyst / ligand complex are selected to control the rate of surface polymer formation.

13. A method according to any one of claims 2-4, wherein the ty pe of the monomer, and the relative amount of the catalyst / ligand to the balance of the amount of the reaction composition are selected to control the rate of surface polymer formation.

14. A method according to any one of claims 2-4, wherein the relative amount of the monomer to the balance of the amount of the reaction composition, and the relative amount of the catalyst / ligand to the balance of the amount of the reaction composition are selected to control the rate of surface polymer formation.

15. A method according to any one of claims 1 to 14, wherein the rate of surface polymer formation is selected to be linear so as to have a coefficient of determination, R2, during a selected time interval of polymerization above or equal to 0.95.

16. A method according to any one of claims 1 to 14, wherein the rate of surface polymer formation is selected to be non-linear so as to have a coefficient of determination, R2, during a selected time interval of polymerization below 0.95.

17. A method according to any one of claims 1 to 14, wherein the rate of surface polymer formation is selected to be linear in a first time interval, and plateaued in a second time interval.

18. A method according to claim 17, wherein the surface polymerization is approaching or reaching a plateau within the second time interval.

19. A method according to claim 17, wherein the surface polymerization is stopped during the second time interval.

20. A method according to any one of claims 1 to 19, wherein the first solvent is present in an amount of 20 Vol% to 80 Vol%, calculated according to formula (I)VolumeFirst solventVol%(First solvent) = - (I)Volumeiotai wherein VolumeFirst solvent is the volume of the first solvent, and wherein VolumeTotai is the volume of the first solvent, the second solvent, the monomer, the catalyst / ligand complex including any solvent, and the catalyst activator including any solvent.

21. A method according to any one of claims 1 to 20, wherein the ligand is selected fromN, N, N’,N”, V"-pentamethyldiethylene-triamine (PMDETA), tris [2-(dimethylamino)ethyl] amine (MeeTREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1 , 1 ,4,7, 10, 10-hexamethy Itri ethylenetetramine (HMTETA), tetramethylethylenediamine(TMEDA), l,4,8,l l-tetramethyl-l,4,8,l l-tetraazacyclotetradecane (MeiCyclam). and / or 2,2’- bipyndyl (BiPy).

22. A method according to any one of claims 1 to 21, wherein the catalyst / ligand complex is a complex selected from Cu / PMDETA, Cu / MeeTREN, Cu / TREN, Cu / TPMA, Cu / HMTETA, Cu / TMEDA, Cu / Me4Cyclam, and Cu / BiPy.

23. A method according to any one of claims 1 to 22, wherein the activator is selected from sodium ascorbate (NaAsc). ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, glucose with GOx, and / or pyrogallic acid.

24. A method according to any one of claims 1 to 23, wherein the first solvent has a dielectric constant, k, in the range of 5 to 80.

25. A method according to any one of claims 1 to 24, wherein the first solvent is selected from methanol, ethanol, and isopropanol.

26. A method according to any one of claims 1 to 25, wherein the second solvent is water.

27. A method according to any one of claims 1 to 26, wherein the solvent further comprises a third solvent selected from aprotic solvents.

28. A method according to claim 27, wherein the third solvent is one or more of acetone, acetonitrile and dimethylsulfoxide (DMSO).

29. A method according to any one of claims 1 to 28, wherein the monomer is selected from methyl methacrylate (MMA). 2-hydroxyethylmethacrylate (HEMA), te / 7-butylmetacrylate (tBMA), acrylic acid (AA), methacrylic acid (MAA), styrene, and glycidyl methacrylate (GMA).

30. A method according to any one of claims 1 to 29, wherein the formed surface polymer has an average dry film thickness of no more than 50 nm.

31. A method according to claim 30, wherein the surface polymer is formed within 30 seconds to 30 minutes.

32. A method according to any one of claims 1 to 29, wherein the formed surface polymer has an average dry film thickness of no more than 25 nm.

33. A method according to claim 32, wherein the surface polymer is formed within 30 seconds to 30 minutes.

34. A method according to any one of claims 1 to 29, wherein the formed surface polymer has an average dry film thickness of no more than 10 nm.

35. A method according to claim 34. wherein the surface polymer is formed within 30 seconds to 30 minutes.

36. A method according to any one of claims 1 to 29 wherein the formed surface polymer has an average dry film thickness of no more than 5 nm.

37. A method according to claim 36, wherein the surface polymer is formed within 30 second to 30 minutes.

38. A reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of no more than 50 nm.

39. A reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent,in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of no more than 25 nm.

40. A reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of no more than 10 nm.

41. A reaction composition comprising a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, in relative amounts to the balance of the amount of the reaction composition and / or types providing an average dry film thickness of no more than 5 nm.

42. A polymer formed on a surface of a substrate by the method according to any one of claims 1 to 37, wherein the applied relative amounts and / or types of two or more of the first solvent, the second solvent, monomer, the catalyst and ligand forming a catalyst / ligand complex, and the catalyst activator are selected to control the rate of surface polymer formation.

43. A system for forming surface polymers on a substrate, the system comprising: a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, anda solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts of and / or types of the first solvent and the second solvent are selected to control the rate of surface polymer formation, and a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers of a specified average dry film thickness to be formed on the portion of the polymerization initiator-modified substrate.

44. A system for forming surface polymers on a substrate according to claim 43, the system comprising: a reaction composition container containing a reaction composition, said reaction composition comprising: a monomer, a catalyst and a ligand forming a catalyst / ligand complex, a catalyst activator, and a solvent comprising a first solvent having an alcohol functional group, being a hydroxyl functional group on an aliphatic carbon atom, and a second solvent miscible with the first solvent, wherein the relative amounts to the balance of the amount of the reaction composition and / or types of two or more of the monomer, the catalyst / ligand complex, the catalyst activator, the first solvent, and the second solvent are selected to control the rate of surface polymer formation, and a substrate displacement device for bringing at least a portion of a polymerization initiator-modified substrate into contact with the reaction composition in the reaction composition container for a controlled time, wherein the controlled time is sufficient for surface polymers of a specified average dry film thickness to be formed on the portion of the polymerization initiator-modified substrate.

45. A system of claim 43 or 44, wherein the substrate displacement device comprises any one of: a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism.

46. A system according to any one of claims 43 to 45, further comprising a polymerization initiator container containing a polymerization initiator agent, wherein the substrate displacement device is configured to bring the at least a portion of the substrate for attachment of polymerization initiators into contact with the polymerization initiator agent to form polymerization initiators at the substrate surface, prior to bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition.

47. A system according to any one of claims 43 to 46 comprising one or more cleaning containers, the cleaning containers containing cleaning agents, wherein the substrate displacement device is configured to bring the at least a portion of the polymerization initiator-modified substrate into contact with the cleaning agents of the one or more cleaning containers prior to, or subsequent to, bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition, and / or the substrate displacement device is configured to bring the at least a portion of substrate into contact with the cleaning agents in the one or more cleaning agents prior to, or subsequent to, bringing the at least a portion of the substrate into contact with the polymerization initiator.

48. A system according to any one of claims 43 to 47, further comprising a container for prewetting the at least a portion of the substrate prior to bringing the at least a portion of the substrate into contact with the reaction composition.

49. A system according to any one of claims 43 to 48, further comprising a reaction composition management system.

50. A system according to claim 49, wherein the reaction composition management system comprises one or more sensors in relation to the reaction composition container.

51. A system according to claim 50, wherein the sensors are configured to measure the pH of the reaction composition or the molecular oxygen concentration in the reaction composition.

52. A system according to any one of claims 43 to 51 , further comprising one or more flow control devices.

53. A system according to claim 52, wherein the one or flow control devices are selected from circulation pumps, flow guidance grids, filters, and / or mechanical stirring means.

54. A system according to any one of claims 43 to 53, further comprising a heating device for annealing the substrate prior to, or subsequent to, bringing the at least a portion of the polymerization initiator-modified substrate into contact with the reaction composition.

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