Surface polymerization control

Abstract

Reaction compositions for forming surface polymers can include at least one monomer, at least one ligand and at least one catalyst that form a complex, at least one solvent, and at least one polymerization control agent for controlling at least one of pH and molecular oxygen concentration. Systems and methods utilizing these reaction compositions to form surface polymers are described.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 440,145, filed January 20, 2023, entitled "Reaction compositions for surface polymerization, methods for forming surface polymers on a substrate and systems for performing the methods," and Danish Application No. PA 2023 70032, filed January 20, 2023, entitled "Reaction compositions for surface polymerization, methods for forming surface polymers on a substrate and systems for performing the methods," both of which are incorporated herein by reference in their entireties.

[0002] Embodiments of the present disclosure generally relate to controlled polymer growth on surfaces, as well as to reactant compositions for controlled surface polymerization, methods of controlled surface polymerization, and apparatus for forming surface polymers on substrates. [Background technology]

[0003] Well-defined polymer structures on surfaces are becoming increasingly important in many technologies and applications. "Surface polymers" or "surface-bound polymers" refer to polymer structures with polymer chains chemically bound to a surface at one end via a covalently attached polymerization initiator. Two methods known to those skilled in the art can be used to achieve such polymer structures: the "grafting-to" approach and the "grafting-from" approach (see Figures 1a and 1b). In the "grafting-to" approach, the polymer is pre-prepared in solution and then deposited on the surface in question. This is because the pre-prepared polymer is designed so that one of the chain ends has some affinity for the target surface. Upon contact with the target surface, the polymer self-assembles on the surface to form a surface-bound polymer. In the "grafting-from" approach, a small molecule capable of acting as a polymerization initiator is covalently attached to the target surface in a pre-polymerization step. Polymerization is then initiated via the polymerization initiator. Thus, the surface polymer is formed from the surface.

[0004] The "grafting-to" approach allows for a simple preparation procedure in that polymers can be prepared using conventional polymerization methods and stored before initiating the self-assembly procedure. However, the "grafting-to" approach lacks the ability to form dense, surface-bound polymer structures. The main problem is that upon self-assembly on a surface, steric repulsion between pre-prepared polymers halts the self-assembly process (see Figure 1a). The "grafting-from" approach allows for the formation of dense, surface-bound polymer structures because small molecules can form more densely packed layers on the surface (compared to large polymer molecules, see Figure 1b). Thus, surface-bound polymer structures formed by the grafting-from approach result in much higher densities. Furthermore, because the "grafting-from" approach allows for dense, surface-bound polymer structures, brush-like structures can be achieved, hence the name "polymer brush." ​​In these structures, the polymers are stretched and forced to stand upright as a result of steric repulsion between neighboring polymers, creating a unique structure known to those skilled in the art as a "polymer brush" structure. On a surface, the structures are tethered / attached, usually covalently, at one end to a surface, typically a solid or semi-solid surface, thereby differing from polymers that are formed in solution and then deposited onto a surface.

[0005] As mentioned above, surface polymers are prepared by one of 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 has several drawbacks and limitations that make it difficult to produce thick, dense surface polymers. In the "grafting from" approach, surface polymer growth (surface polymer chain growth, chain extension by monomer units) is initiated from an initiator-functionalized surface using controlled / "living" polymerization techniques such as anionic polymerization, cationic polymerization, ring-opening polymerization, and radical polymerization, among others.

[0006] Thus, a surface polymer in this context is a polymer structure having polymer chains chemically attached at one end to a surface. Such surface polymers can be tailored to provide specific chemical and / or physical properties, creating precisely tailored chemical structures on a molecular scale. They can be used, for example, to store specific chemical species, control transport properties, improve surface stability and properties, create interfaces where dissimilar materials can bond or interact, and for other functions. Surface polymers can then join otherwise incompatible materials, such as metals and plastics, and improve adhesion between otherwise incompatible materials (see, e.g., WO 2014 075695).

[0007] Different polymerization techniques have facilitated the specific design and synthesis of surface polymers with precise molecular control and desired properties. In particular, surface polymers can be considered as nanoscale "building blocks" with a wide range of applications, from redox activity to biocompatibility and surface modification, and the flexibility of surface polymers allows the creation of thin films of surface polymers that are highly tailored in terms of chemical composition, thickness, grafting density, and architecture.

[0008] Several methods for forming surface polymers are known, including 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 activator (regeneration) 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 (auxiliary activator and reducing agent atom transfer radical polymerization).

[0009] When forming a surface polymer, a polymerization initiator is first formed on the surface on which the surface polymer is to be formed. Secondly, the surface is contacted with an appropriate monomer, catalyst, ligand, and optionally a solvent, or with an appropriate monomer, catalyst, ligand, reducing agent, and optionally a solvent, whereby the surface polymer can be formed using specific reaction conditions. The polymerization initiator and monomer are selected to suit the purpose and properties of the resulting surface polymer. The surface polymer can be formed as a layer of surface polymer, for example, by repeating the polymer structure using different starting monomers (block copolymers).

[0010] Among these known procedures for the formation of surface polymers, (ARGET)ATRP and SET-LRP are widely used. For polymer chain growth, monomers, catalysts, ligands, and solvents are required. In (ARGET)ATRP and SET-LRP polymerizations, some reactions activate the catalyst, thereby promoting polymerization, while other reactions deactivate the catalyst and hinder polymerization. SARA-ATRP and SET-LRP are described, for example, at https: / / www.cmu.edu / maty / atrp-how / procedures-for-initiation-of-ATRP / SARA-ATRP-or-SET-LRP.html.

[0011] Both the SET-LRP and (ARGET) ATRP methods rely on the formation of a complex between a ligand and a halide formed with a transition metal (typically CuCl2 or CuBr2 for ARGET ATRP and Cu(0) for SET-LRP, although other transition metals and halogens may be used).

[0012] ARGET ATRP involves the deactivated halogen-capped species, P n -X and Cu(I)X catalyst, which involves halogen transfer, and the propagating radical (P nThis results in the formation of Cu(I)X and Cu(II)X2. The propagating radical polymerizes with the monomer, forming a growing polymer chain. Controlling the ratio between Cu(I)X and Cu(II)X2 allows for control of the polymerization itself, as is well known for these types of polymerization.

[0013] In ARGET ATRP, a reducing agent (such as ascorbic acid or sodium ascorbate) is added to the polymerization to continuously regenerate active Cu(I)X species from inactive Cu(II)X2 (the latter species inevitably forms from termination events in the ATRP process). In the classical ARGET ATRP process, maintaining control of the ATRP equilibrium remains important, which is also affected by the concentration of the reducing agent. The reducing agent is used in very small amounts to maintain control of the polymerization. The ARGET ATRP procedure is oxygen-sensitive and can tolerate only small amounts of oxygen (the reaction vessel is sealed when the reagents are mixed). Scavenged oxygen is removed by the addition of the reducing agent, a process known as an "incubation" process. The reaction vessel must be sealed during the polymerization because exposure to atmospheric oxygen rapidly quenches the polymerization reaction due to the oxidation of the active Cu(I)X catalyst to the inactive Cu(II)X2 form. The polymerization reaction is further promoted by the presence of catalytically active Cu, and the kinetics of polymerization are controlled using the equilibrium between an activated catalyst, such as Cu(I)X / L species (where L is a ligand and X is a halogen), and a deactivated catalyst, such as Cu(II)X / L species. This equilibrium is difficult to control, making many methods of forming surface polymers unpredictable and short-lived. Furthermore, a major drawback of the prior art is the sensitivity of the system to oxygen, as discussed above. Molecular oxygen (O) can oxidize species that can be used as activated catalysts in surface polymerization, such as Cu(I)X / L species, to generate species that can be used as deactivated catalysts in surface polymerization, such as Cu(II)X / L species. Thus, in the presence of O, the catalytic species may be predominantly present in a form that deactivates surface polymerization, slowing surface polymer formation. A solution to this problem has been to perform the reaction in an O-free atmosphere; however, in such cases, the polymerization solution remains short-lived because the system is exposed to oxygen during handling of the materials from which the surface polymer is formed. In SET-LRP, Cu(0) in solid form (powder, nanoparticles) is used along with a ligand.In the SET-LRP procedure, the Cu catalyst is extracted from the solid Cu present in the reaction composition, and therefore the catalyst concentration increases during the polymerization process, making it difficult to control the kinetics. Therefore, the polymerization solution can only be used once, making the prior art methods unsuitable or impractical for mass production (HVM) of surface polymers. These drawbacks make the uniform growth of surface polymers with highly stable kinetics extremely difficult.

[0014] WO 2019 196999, the entire contents of which are incorporated by reference as if fully set forth herein, discloses an alternative oxygen-tolerant method for forming surface polymers. The catalyst / ligand complexes described in WO 2019 196999 are halogen-free unless the catalyst / ligand complex formed is complexed with a halogen anion. The advantage of this method is that the complex formed between the transition metal and the ligand is inert (i.e., unavailable to initiate polymerization of monomers) and stable (oxygen-insensitive), yet the system can be activated "on demand" to initiate polymerization and growth of surface polymers.

[0015] To fully exploit the potential of surface polymer technology, efficient methods for forming surface polymers are needed on both small research and development scales and large mass production scales. Summary of the Invention

[0016] According to one aspect of the present disclosure, a reaction composition for surface polymer formation is provided, which comprises at least one monomer, at least one ligand and at least one catalyst, the at least one ligand and at least one catalyst forming a complex, at least one catalyst activator, at least one solvent, and at least one polymerization control agent. Furthermore, the at least one polymerization control agent may be at least one pH control agent for controlling the pH of the reaction composition during surface polymer formation. Furthermore, the at least one polymerization control agent may comprise at least one pH control agent for controlling the pH of the reaction composition during surface polymer formation and at least one oxygen control agent for controlling the molecular oxygen concentration in the reaction composition during surface polymer formation. Furthermore, the at least one pH control agent controls the pH of the reaction composition to a pK α formed between the at least one catalyst and the at least one ligand. a Furthermore, the at least one pH control agent may maintain the pH of the reaction composition above the pK H value formed between the at least one catalyst and the at least one ligand. a Furthermore, the at least one pH control agent may maintain the pH of the reaction composition above the pK value of the complex formed between the at least one catalyst and the at least one ligand. a Furthermore, the at least one pH control agent may maintain the pH of the reaction composition above the pK value of the complex formed between the at least one catalyst and the at least one ligand. a H1 and pK a The at least one pH control agent may maintain the pH of the reaction composition at above 6, and in some embodiments, between 8 and 12. The at least one pH control agent may be a buffering agent. The at least one pH control agent may be an acid or a base. The at least one polymerization control agent may be at least one oxygen control agent for controlling the molecular oxygen concentration in the reaction composition. The at least one oxygen control agent may maintain a molecular oxygen concentration in the reaction composition that corresponds to a partial pressure of 25 hPa or less. The at least one oxygen control agent may include an oxygen scavenger. The reaction composition for surface polymer formation may include a pH control agent, or an oxygen control agent, or a pH control agent and an oxygen control agent.

[0017] In particular, the reaction composition may include a solvent, a monomer, a catalyst, a ligand (the catalyst and the ligand form a complex, and the polymerization control agent is a pH control agent), or a pH control agent and an oxygen control agent.

[0018] According to one aspect of the present disclosure, there is provided a method for forming a surface polymer, the method comprising contacting at least a portion of a polymerization initiator-modified substrate with a reaction composition comprising at least one monomer, the reaction composition comprising at least one ligand, at least one catalyst, the at least one ligand and at least one catalyst forming a complex, at least one catalyst activator, and at least one solvent; controlling the surface polymerization by the pH and / or molecular oxygen concentration of the reaction composition; and optionally adding at least one polymerization control agent to adjust the pH and / or molecular oxygen concentration of the reaction composition. Furthermore, the at least one polymerization control agent can be added at least once during or before the surface polymer formation. The at least one polymerization control agent can be (i) at least one control agent, (ii) at least one oxygen control agent, or (iii) at least one pH control agent and at least one oxygen control agent. The at least one polymerization control agent can function as both a pH control agent and an oxygen control agent.

[0019] According to one aspect of the present disclosure, there is provided a method for forming a surface polymer, the method comprising: providing a reaction composition comprising at least one monomer, the reaction composition comprising at least one ligand, at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; and at least one solvent, the reaction composition being held in a reaction composition vessel; contacting at least a portion of a first polymerization initiator-modified substrate with the reaction composition in the reaction composition vessel, thereby forming a surface polymer on said first substrate; removing said first substrate from the reaction composition in the reaction composition vessel; subsequent to removing said first substrate, contacting at least a portion of a second polymerization initiator-modified substrate with the reaction composition in the reaction composition vessel, thereby forming a surface polymer on said second substrate; and removing said second substrate from the reaction composition in the reaction composition vessel; wherein pH and / or molecular oxygen concentration in the reaction composition may optionally be controlled by at least one polymerization control agent. The reaction composition can be modified during surface polymer formation by adding additional components of the reaction composition and / or removing bulk polymer by-products. The pH of the reaction composition and / or the molecular oxygen concentration in the reaction composition can be controlled by measuring the pH and / or the molecular oxygen concentration during surface polymer formation in combination with the supply of at least one polymerization control agent. Multiple substrates can be subjected to surface polymer formation in a reaction composition vessel in a continuous manner. The pH of the reaction composition can be adjusted to control the kinetics of surface polymer formation.

[0020] According to one aspect of the present disclosure, a system for forming a surface polymer on a substrate is provided. The system may include a reaction composition vessel containing a reaction composition, which may include at least one monomer, at least one ligand, at least one catalyst (wherein the at least one ligand and the at least one catalyst form a complex), at least one catalyst activator, and at least one solvent; and a substrate transfer device for contacting at least a portion of a polymerization initiator-modified substrate with the reaction composition in the reaction composition vessel for a controlled time, the controlled time being sufficient to allow a surface polymer to form on the portion of the polymerization initiator-modified substrate. According to at least some embodiments, the substrate transfer device may comprise any one of a conveyor system, a programmable mechanical arm, or a roll-to-roll mechanism. In some embodiments, the system may further include one or more sensors, each configured to measure a different value of a property of the reaction composition; one or more dispensers configured to dispense one or more polymerization control agents and / or one or more components of the reaction composition into the reaction composition; and a control unit operably connected to the one or more sensors, wherein the control unit may be configured to output a control signal to the one or more dispensers to dispense the polymerization control agent and / or one or more components of the reaction composition into the reaction composition. According to some embodiments, the control unit is configured to periodically output a control signal to the dispenser, causing the dispenser to periodically dispense the polymerization control agent and / or components of the reaction composition into the reaction composition. According to some embodiments, the control unit may be configured to output the control signal in response to receiving a sensor signal indicating a change in the value of the property of the reaction composition. In some embodiments, the control unit may be configured to output the control signal in response to receiving a sensor signal indicating a measured value of the property of the reaction composition that does not conform to a predetermined threshold value for the property of the reaction composition. The predetermined threshold value may be a pH value and / or a molecular oxygen concentration. The output control signal may cause the pH control agent and / or the oxygen control agent to be dispensed into the reaction composition.According to some embodiments, the components of the reaction composition may include 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 system may further include a polymerization initiator container containing a polymerization initiator, and the substrate transfer device is configured to contact a portion of the substrate to which the polymerization initiator is to be attached with the polymerization initiator before contacting the portion of the polymerization initiator-modified substrate with the reaction composition to form a polymerization initiator on the substrate surface. The system may include a cleaning container containing a cleaning agent, and the substrate transfer device may be configured to contact a portion of the polymerization initiator-modified substrate with the cleaning agent before or after contacting the portion of the polymerization initiator-modified substrate with the reaction composition, or the substrate transfer device may be configured to contact a portion of the substrate with the cleaning agent before or after contacting the portion of the substrate with the polymerization initiator. Some embodiments may include an annealing vessel containing an annealing agent, and the substrate transfer device may be configured to contact a portion of the substrate with the annealing agent before or after contacting the portion of the substrate with the polymerization initiator, or before or after contacting the portion of the substrate with the reaction composition.

[0021] According to a further aspect of the present disclosure, a system for forming a surface polymer on a substrate is provided. The system may include a reactant composition container, a cleaning container, a polymerization initiator container, and a substrate transfer device. The system may further include an annealing container and / or a drying container. According to some embodiments, the function of the cleaning container may include one or more of etching, thermal cleaning, and removal of surface contaminants, by-products, and residual process chemicals. The system may be for forming a surface polymer with stable kinetics according to the methods disclosed herein.

[0022] At least some embodiments of the present disclosure provide solutions to the aforementioned problems of the prior art by providing reaction compositions and methods involving the controlled formation of surface polymers, particularly polymer brushes. Surprisingly, it has been discovered that controlling specific reaction conditions during surface polymer formation stabilizes the activity of the reaction composition, thereby ensuring stable and consistent kinetics of surface polymer formation, reducing undesirable side reactions, and providing unique control over the surface polymer formed and its thickness. Furthermore, the present disclosure herein allows for the reuse of the reaction composition for multiple surface polymer formation events on a substrate in a sequential manner.

[0023] Thus, the present disclosure enables high volume manufacturing (HVM) as well as smaller scale manufacturing of substrates with surface polymers.

[0024] Certain embodiments of the present disclosure are illustrated in the accompanying drawings, which, however, are not intended to limit the disclosure in any way. [Brief explanation of the drawings]

[0025] [Figure 1] General strategies for a) the "grafting to" approach and b) the "grafting from" approach are shown, where a) shows the steric hindrance of the preformed polymer when attaching to the surface and b) shows the uprightness of the polymer formed from the monomer units, which ensures a higher density of formed polymer than a) (polymer occupation from more initiator sites than is possible with the "grafting to" approach). [Figure 2] The general process of ATRP polymerization reaction is shown below. [Figure 3] Theoretical stable surface polymer formation kinetics for the case of a linear dependence between surface polymer length and polymerization time is shown. [Figure 4] Theoretical stable surface polymer formation kinetics in the case of a nonlinear dependence between surface polymer length and polymerization time is shown. [Figure 5]The polymerization in Figure 3 shows that the variation in thickness of the surface polymer formed varies by + / - 15%. [Figure 6] The polymerization is shown in Figure 4, where the variation in thickness of the surface polymer formed is + / -15%. [Figure 7] FIG. 1 is a schematic diagram of a system for forming a surface polymer on at least a portion of a substrate, according to one embodiment. [Figure 8] FIG. 2 is a schematic diagram of an exemplary substrate transfer device comprising a roll-to-roll processing device, according to one embodiment. [Figure 9] FIG. 8 is a detailed schematic diagram of a reaction composition vessel containing the reaction composition shown in FIG. 7. [Figure 10] 1 is a process flow chart illustrating an iterative process for controlling the pH of a reaction composition, according to one embodiment. [Figure 11] 1 is a process flow diagram illustrating an iterative process for controlling the oxygen content of a reaction composition, according to one embodiment. [Figure 12] 10 is a process flow diagram illustrating different processing steps involved in a system for forming a surface polymer, according to a further embodiment. [Figure 13] See Example 5, showing molecular oxygen concentration after addition of sodium ascorbate. [Figure 14] See Example 5, showing polymer brush thickness, pH and O2 partial pressure as a function of time. [Figure 15] 1 shows the dry film thickness on the substrate obtained by the procedure described in Example 5. [Figure 16] See Example 6, which shows the resulting polymer brush thickness and O2 partial pressure as a function of time. [Figure 17] See Example 6, which shows the thickness of the surface polymer over a 120 minute reaction composition life. [Figure 18] See Example 7, which shows dry film thickness as a function of time. [Figure 19] See Example 7, which shows pH as a function of time. [Figure 20]See Example 8, which shows UV / Vis data for CuCl2, Me6TREN, and CuCl2 + Me6TREN, respectively. [Figure 21] 1 shows the titration curve from the experiment of Example 8. [Figure 22] See Example 9, which shows the dry film thickness of the surface polymer formed on stainless steel as a function of time after activation of the catalyst / ligand complex. [Figure 23] See Example 9, which shows the dry film thickness of the surface polymer formed on a silicon wafer as a function of time after activation of the catalyst / ligand complex. [Figure 24] See results obtained in Example 9, showing pH measured over time. [Figure 25] See Example 10, which shows the dry film thickness of the surface polymer as a function of time after activation of the catalyst / ligand complex of the reaction composition. [Figure 26] See Example 10, which shows continuous measurements of pH and O2 partial pressure. [Figure 27] See Example 11, which shows the surface polymer thickness, pH and O2 partial pressure measured as a function of time. [Figure 28] See Example 12 (Figure 28), which shows bulk polymer formation depending on the pH of the reaction composition: Composition A shown, Composition B shown, Composition C shown, Composition D shown (which was also representative of compositions E and F). [Figure 29] See Example 12, which shows the resulting surface polymer thickness as a function of polymerization time. [Figure 30] See Example 12, which shows pH as a function of time. [Figure 31] See Example 13, which shows surface polymer thickness and pH measurements taken as a function of time. [Figure 32] See Example 14, which shows a comparison of degrafted PMMA-b-PST (block copolymer) with reference spectra for PMMA and PST. [Figure 33] See Example 15, which shows ellipsometric data, O2 and pH measurements. DETAILED DESCRIPTION OF THE INVENTION

[0026] In a first aspect, the present disclosure provides a reaction composition for surface polymer formation, comprising at least one monomer, at least one ligand, at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex, at least one catalyst activator, at least one solvent, and at least one polymerization control agent. The inventors have discovered that using this reaction composition, the kinetics of surface polymer formation are controllable and remain stable for extended time frames. In particular, the polymerization control agent can be at least one pH control agent for controlling the pH of the reaction composition during surface polymer formation. In particular, the polymerization control agent can be at least one oxygen control agent for controlling the molecular oxygen concentration (dissolved O) in the reaction composition. In some applications, the reaction composition can include both at least one pH control agent and at least one oxygen control agent. The thickness of the formed surface polymer is an indicator of successful surface polymer formation, both on a small scale and, particularly, on a large scale (mass).

[0027] The term "kinetics" in the context of surface polymer formation means that, within a given time frame, surface polymerization (polymer chain growth) occurs as a function of time to the extent that a constant surface polymer thickness is obtained. In some cases, the relationship between surface polymer thickness and polymerization time is linear, as illustrated by Figure 3. In other cases, the relationship between surface polymer thickness and polymerization time is nonlinear, as illustrated by Figure 4.

[0028] The expression "stable kinetics" means that the thickness of the surface polymer formed over multiple surface polymer formation events of the same duration (on multiple substrates in a sequential or consecutive manner) is within + / - 20%, preferably within + / - 15%, of the average thickness obtained over the lifetime of the reaction composition and / or the number of substrates subjected to surface polymer formation. The lifetime is defined as the time frame over which the thickness of the surface polymer formed does not deviate from this range.

[0029] Generally, three types of surface polymer "coatings" are known, namely: 1) Preformed polymers that are deposited onto a substrate, for example, by doctor blading or spin coating a dilute solution of the polymer in a suitable solvent as a polymer melt by a molding process. In this method, no covalent bond is formed between the polymer and the surface, and specific reactive groups are not present on both the substrate surface and the polymer itself. If such reactive groups are present on both the polymer and the substrate surface, the polymer is "grafted," as described further below.

[0030] 2) "Grafting to" is a method of attaching polymer chains to a surface. The polymer chains are covalently attached to the surface at one chain end. Methods involving preforming polymers in solution are known to those skilled in the art, with the polymers having reactive chain end groups. In solution, these polymers are not yet attached to a surface. The reactive end groups can react with appropriate reactive groups on the surface in question. Typically, the reactive groups are deposited on the surface or preformed in another way. The preformed polymer is brought into solution, where the conformation of the individual polymer chains is subjected to solvent interactions and energy. Generally, the chains adopt some version of a coiled coil to maximize entropy. This conformation is maintained when the reactive chain end reacts with a reactive group on the surface. The area occupied by grafting this polymer coil to a surface is generally much larger than the area occupied by the reactive surface group, and therefore, adjacent reactive surface groups are blocked from reaction by the polymer coil. Theoretically, much higher polymer graft densities can be achieved if the chains are grafted to a surface in an extended, linear conformation. However, given the entropically favored coiled-coil conformation that the chains adopt in solution, such a conformation is not achievable for polymers in solution. Straight and linear polymer conformations are entropically highly unfavorable and therefore not generally observed for polymers in solution. However, surface polymer coatings consisting of polymer chains with a more linear conformation attached to the surface at a higher density can be obtained using the "grafting from" methodology described below.

[0031] 3) In the "grafting from" method, the surface to be modified with the surface polymer is first modified with molecules containing a polymerization initiator. The polymerization initiator is covalently attached. As mentioned above, given the small size of such initiator molecules relative to the coiled-coil polymer, the density of such initiators on the surface can be much higher than that achieved by directly grafting the polymer coiled-coil onto the surface in the "grafting to" approach described above. Following the modification / deposition of the polymerization initiator, polymer chains grow from these surface-anchored initiators by extension of the polymer chains with monomer units. The conformation of these polymers is governed by entropy, as described above, but also by the fact that the high density of initiators on the surface means that each formed polymer chain interacts with its neighbors, resulting in steric repulsion. Thus, the conformation of these chains is a balance between entropy favoring the coiled-coil and the steric constraints imposed by the high density of polymer chains, which force the chains to stretch away from the surface and occupy as little space as possible. As a result, the polymer chains are stretched away from the surface, reducing steric interactions, even though this conformation has lower entropy than, for example, a coiled coil. Polymer chains covalently anchored at one end to a surface and constrained to an extended conformation are considered a special type of surface polymer, i.e., a "polymer brush." ​​Polymer brushes can only be formed by a "grafting-from" approach, which avoids the low grafting density achieved by the "grafting-to" approach described above.

[0032] The term "surface polymer thickness" should be understood to mean the surface polymer formed by growing polymer chains (extending polymer chains by monomer units) from a polymerization initiator on the surface of a substrate during a specified time that the substrate is in contact with a reactive composition. Thickness is often measured as dry film thickness by ellipsometry.

[0033] Thus, substantially uniform formation of surface polymer in successive surface polymer formation events is possible when similar time frames and conditions for surface polymer formation are implemented, i.e., when each substrate remains in the reaction composition for a predetermined time. Thus, a target surface polymer thickness can be obtained within a given applied polymerization time, which is within + / - 20%, preferably + / - 15%, of the average thickness obtained during multiple surface polymer formation events, as determined by the dry film thickness of the collapsed surface polymer.

[0034] In the above scenario, control of the polymerization kinetics is a desirable aspect. Figure 2 shows the general pathway of known ATRP processes, where the rate constant k 活性化 and k 不活性化 The equilibrium between the inactive alkyl halide and the active propagating alkyl radical, as determined by

[0035] In general, surface polymer formation or growth (extension of a polymer chain by a monomer unit) is a repeatable process that depends on the active propagating alkyl radical and the monomer unit, resulting in a surface polymer of a specific thickness. Ultimately, the thickness of the resulting surface polymer is a direct result of the number of successful propagation events. Certain processes, for example, through recombination and disproportionation between two alkyl radicals, can irreversibly deactivate an active propagating alkyl radical, resulting in a polymerization rate that decreases over time. These processes can be grouped as termination events (i.e., the growth in the polymer chain is terminated). Note that such terminations affect surface polymer growth on the specific substrate on which they occur, but do not affect the polymer formation ability of the reaction composition as a whole. Replacing a substrate with a high degree of termination in the reaction composition with a substrate modified with an unterminated initiator can result in surface polymer formation on the latter substrate. The delicate balance between active propagating alkyl radicals, activated and deactivated catalytic species, and termination events is generally very easily perturbed by external factors, such as changes in molecular oxygen concentration, by-products formed in the reaction composition, and changes in concentration, which alter the kinetics of the reaction over time, and is particularly applicable to the polymerization processes known as (ARGET)ATRP and SET-LRP. Therefore, the ability to obtain controlled kinetics by controlling specific parameters, as demonstrated herein, is quite surprising given the complex nature of polymerization reactions and polymer chain growth.

[0036] Growth rate (rate constant k p ) compared to the stopping rate (with rate constant k t(having the formula (I)) shows the highest dependence on the concentration of active propagating alkyl radicals. At low concentrations, termination is more highly unfavorable than propagation. Under such conditions, the relationship between surface polymer thickness and polymerization time can be (approximately) linear. In known procedures, measures to reduce the concentration of active propagating alkyl radicals include reducing the catalyst concentration, using less active ligands in the ATRP process, or increasing the concentration of deactivators by adding a halide source. A linear relationship between surface polymer thickness and polymerization time can allow for a high degree of predictability and control of surface polymer thickness by adjusting the polymerization time, at the expense of a lower initial polymerization rate. In contrast, termination at the growing polymer chain end can be favored in known procedures by increasing the concentration of growing alkyl radicals. Measures to increase the concentration of active propagating alkyl radicals include increasing the catalyst concentration or using more active ligands in the ATRP process. A nonlinear relationship between surface polymer thickness and polymerization time can allow for a very high initial polymerization rate, at the expense of irreversible deactivation of polymerization due to termination of growing polymer chain ends over time.

[0037] Controlling the rates of both propagation and termination can allow for a high degree of predictability and control of surface polymer thickness, and indeed can be achieved with the methods disclosed herein, by adjusting the polymerization time or by designing a polymerization that terminates after a desired surface polymer thickness is achieved. Thus, in one embodiment, surface polymers obtained over an extended time frame of the reaction composition are achieved in polymerizations that exhibit a linear relationship between surface polymer thickness (y-axis) and polymerization time (x-axis—polymerization time after activation of the catalyst / ligand complex) (as illustrated in FIG. 3). In another embodiment, surface polymers obtained over an extended time frame of the reaction composition are achieved in polymerizations that exhibit a nonlinear relationship between surface polymer thickness (y-axis) and polymerization time after activation of the catalyst / ligand complex (x-axis) (due to termination events, as illustrated in FIG. 4). In both embodiments, the kinetics of the reaction composition are stable over an extended time frame of the reaction composition, allowing for a high degree of predictability and control of surface polymer thickness (see FIG. 5 for linear kinetics and FIG. 6 for nonlinear kinetics, for illustrations showing a + / −15% deviation from the average thickness of surface polymer on a series of substrates obtained after a given polymerization time).

[0038] In one embodiment, the at least one polymerization control agent is at least one pH control agent for controlling the pH of the reaction composition during surface polymer formation. In one embodiment, the pH control agent adjusts the pH of the reaction composition to below the pK of the complex formed between the catalyst and the ligand. a In one embodiment, the at least one pH control agent may maintain the pH of the reaction above the pK H value of the complex formed between the catalyst and the ligand. a In one embodiment, the pH control agent may maintain the pH of the reaction composition above the pK of the complex formed between the catalyst and the ligand. a In one embodiment, the pH control agent may maintain the pH of the reaction composition above the pK of the complex formed between the catalyst and the complex. a H1 and pK a H2. The complex formed between the catalyst and the ligand may also be referred to herein as a catalyst / ligand complex.

[0039] In this context, pH and acid dissociation constants (pK a values) apply to catalyst / ligand complexes, acids, bases, and solvents, and their mixtures, and are related to pH and pK a Since the catalyst / ligand complexes used herein are basic, the pK of the conjugate acid can be meaningfully determined. a pK refers to a The term pK is used. a The higher the H value, the stronger the base. For species that can be protonated more than once, the pK a H1 is the pK of the conjugate acid obtained after the "first" protonation a pK a H2 is the pK of the conjugate acid obtained after the "second" protonation a In this case, pK a H1 is always pK a Higher than H2, i.e., pK a H1>pK a H2. Specific pK a and pK a H values ​​can be calculated using known titration methods or can be looked up in various publications and handbooks, if available.

[0040] In one embodiment, the polymerization control agent can be at least one oxygen control agent, hi another embodiment, the polymerization control agent can be at least one pH control agent and at least one oxygen control agent.

[0041] The pH control agent may be any substance capable of adjusting the pH of the reaction composition. Because the reaction composition contains components that are miscible or soluble in water, the pH control agent should be soluble in water. The term "water" is intended to mean water of all types and qualities, for example, tap water, deionized water, and ultrapure water.

[0042] In one embodiment, at least one pH control agent can be a buffer. The term "buffer" is defined herein as an agent that, when added to a reaction composition, can withstand a change in pH within a specific pH range when an acidic or alkaline substance is added to or formed in the composition. A buffer system includes a combination of a weak acid and its conjugate base, or a weak base and its conjugate acid. Non-limiting examples of buffers include carbonate buffer, glycine buffer, citrate buffer, phosphate buffer, acetate buffer, ammonium buffer (ammonium chloride / ammonia), formate buffer, sodium ascorbate / ascorbic acid buffer, and zwitterionic buffers, such as Good's buffer. In some embodiments, such buffers can be used as aqueous or non-aqueous solutions. In other embodiments, such buffers can be added as pure substances. Different buffers have different buffering ranges, and in one embodiment, a buffer can be used to adjust the pH of the reaction composition to the pK of the catalyst / ligand complex. a The pH is selected to exceed the H value. For example, a sodium carbonate / sodium bicarbonate buffer system may be used to maintain the pH in the range of 9.2 to 10.8, or a glycine buffer system may be used to maintain the pH in the range of 8.6 to 10.6.

[0043] In one embodiment, the at least one pH control agent may be selected from a carbonate buffer, a glycine buffer, and a phosphate buffer.

[0044] In another embodiment, the at least one pH control agent can be a base or an acid, which can be inorganic or organic. Non-limiting examples of bases are potassium hydroxide (KOH), lithium hydroxide (LiOH), tripotassium phosphate (KPO), sodium carbonate (NaCO), or sodium ethoxide (CHCHONa). Non-limiting examples of acids are methanesulfonic acid (MSA), hydrochloric acid (HCl), sulfuric acid (HSO), phosphoric acid (HPO), 2,2,2-trifluoroacetic acid (TFA), p-toluenesulfonic acid (pTSA), and nitric acid (HNO).

[0045] As used herein, the pH of the polymerization composition is determined by the pK of the catalyst / ligand complex.a It has been shown that by controlling the pH within a specific range above the H value, the stability and kinetics of the desired surface polymer formation can be further controlled over an extended time frame, allowing for the formation of surface polymers on multiple substrates in a sequential manner. a The H value is determined by the nature of the catalyst and ligand, respectively, as this species can assume its most active form within a given pH range. Importantly, the pK of the catalyst / ligand complex a The H values ​​are the individual pK values ​​of the catalyst and the ligand alone (uncomplexed). a The pH value of the reaction composition may be different from the pK H value. In some embodiments, the lower limit of the pH value range is defined as the pH at which the catalyst and ligand no longer form a complex, for example due to over-protonation of the ligand, but may exist as separate species in the reaction composition. In some embodiments, the upper pH value is defined by the regime in which turnover or decomposition (decomplexation) of one or more other components of the reaction composition is significant. In some embodiments, the appropriate pH value of the reaction composition is determined by the pK H value of the first protonation of the catalyst / ligand complex. a H value (pK a H1), i.e., pK a H1<pH of the reaction composition. Depending on the components of the reaction composition, the pH can be, for example, 11, 10, 9, 8, 7, or 6, or any non-integer value in between. The catalyst / ligand complex is strongly coordinated in this range. We have found that the pK a At pHs below H1, protonation of the catalyst / ligand complex is believed to cause the complex to be (partially) inactivated, although some catalytic activity may still be maintained. Further reduction of the pH may result in a second protonation of the ligand. This may occur at a second pK a H value (pK a H2), further reducing the stable kinetics of surface polymer formation.

[0046] In one embodiment of the present disclosure, the control of pH in the reaction composition is achieved by the addition of at least one pH control agent capable of adjusting or maintaining the pH of the reaction composition within a desired pH range. a It is understood that the H value will depend on the nature of the catalyst and ligand. In one embodiment, in which Cu is used as the catalyst and tris[2-(dimethylamino)ethyl]amine (Me6TREN) is used as the ligand, at least one pH control agent controls the pH of the reaction composition to a pK a In another embodiment in which Cu is used as the catalyst and Me6TREN is used as the ligand, the at least one pH control agent may maintain the pH of the reaction composition above pK as defined herein. a H1 and pK a In a third embodiment, in which Cu is used as the catalyst and N,N,N',N",N"'-pentamethyldiethylenetriamine (PMDETA) is used as the ligand, at least one pH control agent may be added to the reaction composition to maintain the pH between pK a In a fourth embodiment in which Cu is used as the catalyst and PMDETA is used as the ligand, the at least one pH control agent may maintain the pH of the reaction composition above pK as defined herein. a H1 and pK a In a fifth embodiment, in which Cu is used as the catalyst and tris(2-pyridylmethyl)amine (TPMA) is used as the ligand, at least one pH control agent may be added to the reaction composition to maintain the pH between pK a In a sixth embodiment in which Cu is used as the catalyst and TPMA is used as the ligand, the at least one pH control agent may maintain the pH of the reaction composition above pK as defined herein. a H1 and pK aBetween pH 6 and pH 7.4, pH 7.4 and pH 7.4 may be maintained between pH 6 and pH 7.4. The upper pH limit is defined by the regime in which turnover or decomposition of one or more components of the reaction composition is significant. In some embodiments, the upper pH limit is 13. Thus, in some embodiments, the pH of the reaction composition should be greater than 6. Preferably, in some embodiments, the pH of the reaction composition should be between 8 and 12. The pK of certain copper-ligand complexes is a The values ​​are summarized in Table 1. pK of certain copper-ligand complexes a The values ​​are summarized in Table 1. The pK a The H2 value was confirmed by UV / Vis spectroscopy to be the pH at which protonation abolished the characteristic absorbance profile of the catalyst / ligand complex, indicating that the complex was not a stable species at that pH. The pK values ​​of other catalyst / ligand complexes not included in Table 1 are shown. a The H2 value can be determined similarly. [Table 1]

[0047] For example, when Cu is used as a catalyst and Me6TREN is used as a ligand, the pK at which the Cu / Me6TREN complex is protonated is a At pHs below H1, the rate of surface polymerization has been shown to decrease (see Example 12). Furthermore, bulk polymer formation increases (see below), which appears to impair the kinetics and lifetime of surface polymer formation. These aspects are related to the pK of the catalyst / ligand complex. a This paper highlights the beneficial effect of controlling pH by taking into account the values.

[0048] In one embodiment of the present disclosure, the concentration of dissolved O in the reaction composition is controlled by adding at least one oxygen control agent capable of maintaining the concentration of dissolved molecular O in the reaction composition below a desired boundary. In one embodiment, the oxygen control agent chemically removes dissolved O in the reaction composition, thereby controlling the molecular oxygen concentration in the reaction composition. The chemical removal of O can be suitably performed by a substance having oxygen scavenging properties. Oxygen scavenging is understood herein as the continuous consumption of molecular oxygen dissolved in the reaction composition. It is currently believed that the primary reaction pathway responsible for beneficial oxygen scavenging is reduction, i.e., the oxygen scavenger can be a substance capable of reducing molecular oxygen dissolved in the reaction composition.

[0049] Non-limiting examples of molecular oxygen control agents include sodium ascorbate (NaAsc), ascorbic acid (Asc), hydrazine, hydrazine hydrate, sodium thiosulfate, sodium sulfite, sodium dithionite, GO. x or an oxygen scavenger such as pyrogallic acid, or glucose having the formula: In some embodiments, the roles of catalyst activator and oxygen control agent are fulfilled by a single substance, for example, by adding an excess amount of catalyst activator, thereby providing full catalyst activation while also achieving an oxygen control effect.

[0050] In another embodiment, the oxygen control agent physically removes O from the reaction composition, which may be suitably achieved by purging with an inert gas such as argon or nitrogen, or by vacuum degassing.

[0051] The amount of O2 in a reaction composition can be measured and expressed in terms of partial pressure. A specific partial pressure in hPa is related to the concentration of M by Henry's law. The information needed to convert the partial pressure p(O2) to the molar concentration [O2] is the Henry's solubility parameter (H s cp ) (for O in H O at room temperature, H s cp =1.3 10 -3 Matm -1), the partial pressure of the species, the temperature of the medium (due to the temperature dependence of the equilibrium constant), and the ionic strength of the medium (due to the typically decreased gas solubility at higher salt concentrations). For a binary solvent mixture, the Henry's law solubility parameters are the individual H for each solvent in their pure form. s cp It depends on the value of the solvent interaction parameter derived from the Wohl expansion of the excess chemical potential (note: 1 hPa is equivalent to 1 mbar). Thus, the concentration of O2 (amount of dissolved O2) in a reaction composition is related to p(O2) (partial pressure of O2) in the reaction composition. For a given reaction composition defined herein, p(O2) should not exceed 25 hPa, i.e., the oxygen control agent should be added in an amount to keep p(O2) below or at 25 hPa during surface polymer formation. The amount of oxygen dissolved in the reaction composition can be measured in hPa using a sensor with sensitivity within this range. Within this context, the amount of oxygen dissolved in the reaction composition can also be referred to as the "concentration of O2" or the "partial pressure of O2."

[0052] Different oxygen control agents can be used depending on their solubility in a particular reaction composition. For example, sodium ascorbate or sodium thiosulfate may be more suitable for aqueous reaction compositions, while hydrazine may be more suitable for non-aqueous reaction compositions.

[0053] As mentioned above, the amount of molecular O2 dissolved in the reaction composition should preferably not exceed 25 hPa to maintain stable kinetics during surface polymer formation. This is believed to minimize the oxidation of the active catalyst / ligand complex to its oxidized, inactivated form. Controlling the molecular oxygen concentration influences the equilibrium between the activated catalyst / ligand complex and its oxidized, inactivated form, providing improved control over the rate of surface polymerization. To initiate surface polymer formation, the activated catalyst / ligand complex reacts with the polymerization initiator to generate a propagating radical that undergoes polymerization with the monomer. Meanwhile, the oxidized, inactivated form of the catalyst / ligand complex can react with the propagating radical to form a capped, dormant species. Dissolved O2 present in the polymerization composition oxidizes the activated catalyst / ligand complex to its oxidized, inactivated form, thereby altering the equilibrium between the activated catalyst / ligand complex and the oxidized, inactivated form, thereby preventing surface polymerization. Meanwhile, the catalyst activator continuously (re)generates the activated catalyst / ligand complex from the oxidized, inactivated catalyst / ligand complex. Due to the high rate at which activated catalyst / ligand complexes can be consumed through oxidation by O2, the continuous generation of activated catalyst / ligand complexes promoted by catalyst activators is completely counteracted by the presence of O2, disabling surface polymerization dependent on activated catalyst / ligand complexes. Furthermore, O2 can also react with active radical chain ends (propagating radicals) to quench polymerization. Therefore, by ensuring that the partial pressure of O2 dissolved in the reaction composition does not exceed 25 hPa, stable kinetics can be obtained for the extended lifetime of the reaction composition.

[0054] In some cases, oxygen control agents may react with O2 present in the reaction composition to form H2O2. H2O2 can further react in a metal-catalyzed Fenton-like reaction (J. Catal. 2013, 301, 54-64.) to generate OH radicals that initiate polymerization in the bulk of the reaction composition. The formation of bulk polymer is undesirable because it (a) alters the reaction composition, potentially reducing its activity and shelf life, and (b) increases the likelihood of post-cleaning due to the bulk polymer's "stickiness" to the substrate. Maintaining a dissolved oxygen partial pressure below 25 hPa minimizes the formation of H2O2 and, therefore, the formation of undesirable bulk polymer. An example of an H2O2-generating oxygen control agent is sodium ascorbate in combination with a Cu catalyst. Importantly, if one or more processes in the reaction composition can continuously and rapidly consume dissolved O2, the reaction composition can be maintained and operated under an ambient atmosphere containing O2 without losing its surface polymerization capability.

[0055] Another reason for maintaining the pH of the reaction composition within a certain range when HO is generated as described above is that under alkaline conditions, the generated HO may decompose into HO and O rather than OH radicals. Therefore, under alkaline conditions, the extent of OH radical formation decreases, ultimately reducing bulk polymerization initiated by OH radicals. Therefore, it may be beneficial to use a reaction composition containing both a pH control agent and an oxygen control agent. Thus, in one embodiment, the polymerization control agent is a pH control agent and an oxygen control agent. In particular, the polymerization control agent may be sodium ascorbate, which functions as both a pH control agent and an oxygen control agent.

[0056] pH>pK aBy controlling H1, the rate of surface polymer formation can be kept high and uniform, and the rate of bulk polymer formation can be kept low. Both factors are important for ensuring an extended reaction composition lifetime (the time frame during which surface polymer can be formed on a substrate without adding and / or removing components from a given bath). pK a H1>pH>pK a In H2, the kinetics of surface polymerization can be kept stable.

[0057] It is desirable to control or limit bulk polymerization, rather than surface-initiated polymerization, resulting in polymeric material that is not covalently bound to the substrate surface. Bulk polymerization involves detrimental aspects to surface polymerization, including (1) consumption over time of components of the reaction composition necessary for surface polymer formation, (2) changes over time in physical parameters of the reaction composition, such as viscosity, which can affect the kinetics of surface polymer formation over time, and (3) chemisorption or physisorption of bulk polymer chains onto growing surface polymers, leading to the formation of non-uniform surface polymers. Regarding (1), bulk polymer formation consumes monomers, which are usually present in finite amounts, and can lead to a lack of monomer availability over time, thus resulting in a slowdown in the rate of surface polymer formation. Regarding (2), the formation of bulk polymers in the reaction composition can result in an increase in the viscosity of the reaction composition, which in turn affects the rate of diffusion-controlled chemical reactions occurring in the reaction composition, complicating the aspect of maintaining uniform performance of the reaction composition over time. Bulk polymers that are not sufficiently solubilized by the reaction composition also involve mechanical problems, such as clogging of the system. Ultimately, this leads to a lack of sufficient process control to ensure consistent and repeatable manufacturing in an HVM environment. Regarding (3), bulk polymer chains can be physisorbed onto the substrate surface, thereby affecting the substrate-liquid interface, for example, by reducing the diffusion of monomers and catalysts to the growing chain ends, ultimately leading to a slower rate of surface polymer formation. Furthermore, growing bulk polymer chains can react (couple) with growing surface polymer chain ends. This can affect the resulting surface polymer, with the surface polymer chains being of different chain lengths, resulting in non-uniform surface polymers.

[0058] A common method for assessing the extent of bulk polymer formation is to measure turbidity using a turbidity sensor in nephelometric turbidity units (NTU). Steps to avoid bulk polymer formation can be taken to maintain turbidity below 500 NTU throughout the life of the reaction composition.

[0059] Due to the above-mentioned detrimental effects, it may be beneficial to limit the rate and extent of bulk polymer formation in the reaction composition, depending on the components of the reaction composition. Therefore, the reaction composition may further include at least one radical inhibitor. Currently, free radical polymerization is believed to contribute to the formation of bulk polymer. Non-limiting examples of such inhibitors include MEHQ (4-methoxyphenol), butylated hydroxytoluene, 4-tert-butylcatechol (TBC), butylated hydroxytoluene (BHT), hydroquinone (HQ), dinitro-ortho-cresol, di-nitro-sec-butylphenol (DNBP), phenothiazine, 2-(hydroxyamino)propanohydroxamic acid (HPHA), and diethylhydroxyamine (DEHA), as well as combinations thereof. Radical inhibitors can react with radical chain ends to terminate polymerization, and therefore, it may be advantageous to add radical inhibitors to the reaction composition to prevent the polymerization of bulk polymers. Radical inhibitors can also react with radicals at the ends of growing surface polymer chains, thereby terminating surface polymer formation. This undesirable effect on surface polymer formation can be minimized by keeping the concentration of radical inhibitor low, for example, 2 ppm or 20 ppm. Radical inhibitors are usually present in commercially available monomers to stabilize the monomer. An alternative method for removing any bulk polymer can be by filtering the reaction composition at an appropriate time. However, it is preferable to minimize the formation of bulk polymer, instead of having to repeatedly remove bulk polymer from the reaction composition.

[0060] HO can also be chemically removed using hydrogen peroxide scavengers to reduce bulk polymer formation. Examples of hydrogen peroxide scavengers include horseradish peroxidase and sodium pyruvate. Additionally, OH radicals generated from HO (in a metal-catalyzed Fenton-like reaction) can also be quenched. Examples of OH radical scavengers include alcohols such as mannitol and n-butanol.

[0061] Reactant compositions according to embodiments of the present disclosure include at least one catalyst activator. Catalyst activators are responsible for the turnover between oxidized, deactivated, and / or activated catalyst states. It is currently believed that the primary reaction pathway for catalyst activation is reduction; i.e., catalyst activators are species capable of reducing the catalyst. Examples of suitable catalyst activators are oxygen scavengers, such as sodium ascorbate, ascorbic acid, hydrazine, hydrazine hydrate, sodium hypophosphite, glucose, stannous 2-ethylhexanoate, sodium phenoxide, sodium dithionite, and mixtures of iron powder and sodium chloride.

[0062] The catalyst of the reaction composition defined herein may be based on a transition metal (as defined in the Periodic Table of the Elements). Suitable examples of transition metals include compounds derived from copper (Cu), iron (Fe), aluminum (Al), cadmium (Cd), tungsten (W), rhenium (Re), ruthenium (Ru), platinum (Pt), titanium (Ti), manganese (Mn), nickel (Ni), samarium (Sm), or palladium (Pd). In one embodiment, the catalyst is based on a transition metal derived from a Cu species and / or an Fe species. Specific examples of such catalysts include CuO, CuO, CuCl, CuCl2, CuBr, CuBr2, FeO, Fe2O3, and Fe2O4, as well as combinations thereof. In a preferred embodiment, the catalyst is Cu-based. In one embodiment, the Cu concentration in the reaction composition is in the range of 0.001 to 1 mM. The concentration of Cu in the reaction composition is preferably in the range of 0.02 to 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., oxygen scavenger) can be used in excess relative to the transition metal. The excess activator can be, for example, 10 to 250 times. According to the method disclosed herein, the catalyst activator can be added several times during surface polymer formation to control surface polymer formation over time.

[0063] Reaction compositions according to embodiments of the present disclosure include at least one ligand capable of forming a complex with the catalyst. The activity of the catalyst can be tuned by smaller, electron-rich organic molecules that can coordinate to the redox-active metal atom of the catalyst. Suitable ligands are therefore bidentate, tridentate, or tetradentate aromatic and aliphatic amines. One, two, or three ligands can form complexes with a single transition metal catalyst. Confirmation of the presence of a specific catalyst / ligand complex can often be obtained using UV / Vis spectroscopy, as such complexes are typically characterized by a characteristic absorption profile in the UV / Vis region. Such UV / Vis spectroscopy is exemplified in Example 8 (see below). It is currently believed that the catalyst / ligand complex, rather than any individual species, is the primary species responsible for catalyzing the ability of the reaction composition to form a surface polymer. In one embodiment, at least one ligand is a nitrogen-containing compound. Non-limiting examples of such nitrogen-containing compounds are aliphatic and / or aromatic bidentate, tridentate, or tetradentate amine ligands (containing two, three, or four amine substituents). In particular, such ligands include those selected from N,N,N',N'',N'''-pentamethyldiethylenetriamine (PMDETA), tris[2-(dimethylamino)ethyl]amine (Me6TREN), tris(2-aminoethyl)amine (TREN), tris(2-pyridylmethyl)amine (TPMA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), tetramethylethylenediamine (TMEDA), 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (Me4Cyclam), and 2,2'-bipyridyl (BiPy), and combinations thereof. The amount of ligand in the reaction composition is defined as the ratio to the concentration of catalyst in the reaction composition. The ratio of ligand to catalyst in the reaction composition ranges from 0.001:1 to 1000:1. The ratio of ligand to catalyst in the reaction composition is preferably in the range of 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. Generally, an excess of ligand compared to the amount of catalyst is preferred.

[0064] In one embodiment, the catalyst is copper (Cu). The active catalyst / ligand complex formed is Cu(I) / L, and the oxidized, inactive form is Cu(II) / L, where L represents the ligand. The equilibrium between Cu(I) / L and Cu(II) / L is used to control surface polymer formation: Cu(I) / L reacts with a surface-attached halide initiator (RX) to generate Cu(II) / LX and a propagating radical, while Cu(II) / LX and the propagating radical combine to generate a dormant species capped with the halide initiator or X and Cu(I) / L. An oxygen scavenging pathway (dissolved O present in the polymerization composition) oxidizes the active Cu(I) / L catalyst to Cu(II) / L, thereby shifting the equilibrium between activated Cu(I) / L and inactivated Cu(II) / L, and consequently preventing surface polymer formation. Due to the high rate at which Cu(I) / L can be consumed through oxidation by O, the continuous generation of Cu(I) / L promoted by the catalyst activator is completely offset by the presence of O, disabling Cu(I) / L-dependent surface polymer formation. As noted above, maintaining the partial pressure of dissolved O in the reaction composition below 25 hPa controls and ensures stable kinetics during the time frame of the surface polymer formation event, minimizing the formation of inactivated Cu(II) / LX and therefore its adverse effects on surface polymer formation.

[0065] The reaction composition according to embodiments of the present disclosure may further include a halide compound to increase the "livingness" of the surface polymer formation. "Living" polymerization refers to surface polymer formation in which the termination rate is small compared to the rate of surface polymer chain growth (extension of the surface polymer by monomer units). As a result, living polymer formation exhibits a linear relationship between polymer chain length and time. Living polymer formation also enables block copolymers to grow. As used herein, a halide compound is a compound capable of providing a halide anion. Non-limiting examples of such compounds are NaCl, NaBr, KCl, KBr, MgCl, MgBr, CaCl, HCl, HBr, LiCl, LiBr, CaBr, CuBr, and CuCl, as well as combinations thereof. The halide compound dissociates in the reaction composition to generate halide anions that can complex with and / or bind to the catalyst in solution, resulting in an increased concentration of catalyst / ligand-X complexes, which are involved in end-capping, and therefore deactivation, the growth of surface polymer chain terminal radicals, delivering alkyl halides. As a result, the number of surface polymer chain-end radicals growing at any given time is reduced, which may have the effect of at least (1) reducing the rate at which the surface polymer initially grows due to the fewer number of growing chains, and (2) increasing the living character of the surface polymer formation by reducing the rate at which chain termination (via recombination or disproportionation) between two growing surface polymer chain-end radicals occurs. In one embodiment, the catalyst is Cu, the ligand is Me6TREN, PMDETA, TREN, HMTETA, TMEDA, or Me4Cyclam, and the halide compound is NaCl.

[0066] According to one aspect, the present disclosure relates to a method of forming a surface polymer, the method comprising contacting at least a portion of a polymerization initiator-modified substrate with a reaction composition comprising at least one monomer, the reaction composition comprising at least one ligand and at least one catalyst, wherein the at least one ligand and at least one catalyst form a complex, at least one catalyst activator, and at least one solvent; controlling the surface polymer formation by the pH and / or molecular oxygen concentration of the reaction composition; and optionally adding at least one polymerization control agent to adjust the pH and / or molecular oxygen concentration of the reaction composition.

[0067] It should be understood that the above steps do not necessarily have to be performed in the order described, i.e., one of the steps may be performed before or after another in some cases.

[0068] Thus, the polymerization control agent may be added (i) before contacting the substrate with the reactive composition, (ii) after contacting the substrate with the substrate, or (iii) when contacting the substrate with the substrate. Furthermore, the polymerization control agent may be added continuously during surface polymer formation or in discrete portions during surface polymer formation.

[0069] The catalyst activator may be suitably added to the reaction composition (i) before contacting the substrate with the reaction composition, (ii) after contacting the substrate with the reaction composition, or (iii) when contacting the substrate with the reaction composition.

[0070] The inventors have recognized that, using the reaction methods described herein, the kinetics of surface polymer formation remain stable for an extended time frame, allowing for the formation of surface polymers (i.e., multiple substrates or portions of substrates) in a continuous manner, in the presence of at least one polymerization control agent included in the reaction composition. In particular, the polymerization control agent may be a pH control agent and / or an oxygen control agent, thus allowing for control of the pH and molecular oxygen (O2) concentration in the reaction composition.

[0071] By enabling surface polymer formation in a continuous manner, it is understood herein that surface polymers can be formed on two or more substrates or portions of a stretched substrate that follow one another in the reactive composition, where the kinetics of surface polymerization are within + / - 20%, preferably within + / - 15%, of the average rate on the two or more substrates or on several portions of the stretched substrate. The ability to form surface polymers with a high degree of uniformity and reproducibility is a highly valuable feature in both small-scale and especially large-scale (mass) formation of surface polymers. At least some embodiments of the present disclosure provide methods for doing so.

[0072] In one embodiment, additional polymerization control agent is added at least once before and / or during successive surface polymer formation events.

[0073] In one embodiment, the method further comprises monitoring and controlling the molecular oxygen concentration in the reaction composition and / or monitoring and controlling the pH of the reaction composition before or during surface polymer formation.

[0074] In one embodiment, the method is applied to form a surface polymer on multiple substrates in a continuous manner. In another embodiment, the method is applied to form a surface polymer on a flexible, elongated substrate that is provided on a roll and can be processed using a roll-to-roll or reel-to-reel mechanism, such as that shown in FIG.

[0075] The molecular O concentration and / or O partial pressure in the solution of the reaction composition during surface polymer formation can be suitably monitored using an O sensor. If monitoring indicates that the molecular O concentration in the solution of the reaction composition has increased, more oxygen control agent can be suitably provided to the reaction composition. The oxygen control agent used in embodiments of the method according to the present disclosure is as defined herein.

[0076] The pH of the reaction composition during surface polymer formation can be appropriately monitored using a pH meter. If monitoring indicates that the pH of the reaction composition rises above or falls below a desired range (threshold), more pH control agent can be appropriately supplied to the reaction composition. The pH control agent used in the embodiments of the disclosed method is as defined herein.

[0077] It is understood that the methods described herein may include one or more of the following: washing the substrate before or after depositing the initiator, washing the polymerization initiator-modified substrate before or after forming the surface polymer, annealing the substrate before or after depositing the initiator, and Annealing the substrate before or after forming the surface polymer.

[0078] In another aspect, the present disclosure relates to a method for forming a surface polymer, the method comprising: providing a reaction composition comprising at least one monomer, at least one ligand and at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; and at least one solvent, the reaction composition being held in a reaction composition vessel; contacting at least a portion of a first polymerization initiator-modified substrate with the reaction composition in the reaction composition vessel, thereby forming a surface polymer on said first substrate; removing said first substrate from the reaction composition in the reaction composition vessel; subsequent to removing said first substrate, contacting at least a portion of a second polymerization initiator-modified substrate with the reaction composition in the reaction composition vessel, thereby forming a surface polymer on said second substrate; and removing said second substrate from the reaction composition in the reaction composition vessel; and optionally controlling pH and / or molecular oxygen concentration in the reaction composition using at least one polymerization control agent. In one embodiment, the reaction composition may be modified during surface polymer formation by the addition of additional components of the reaction composition and / or the removal of bulk polymer by-products. In one embodiment, the pH of the reaction composition and / or the molecular oxygen concentration of the reaction composition may be controlled by measuring the pH and / or the molecular oxygen concentration during surface polymer formation in combination with the supply of at least one polymerization control agent. In one embodiment, multiple substrates are subjected to surface polymer formation in a continuous manner in the reaction composition vessel.

[0079] In one embodiment, the above procedure may be repeated, for example, to form block copolymers applying two or more different monomers in a surface polymerization event.

[0080] In one embodiment, the pH of the reaction composition is adjusted to control the kinetics of surface polymer formation. The terms "kinetic" and "stable kinetic" are explained in more detail above.

[0081] In one embodiment, the above-described method may include one or more of the following: washing the substrate before or after depositing the initiator, washing the polymerization initiator-modified substrate before or after forming the surface polymer, annealing the substrate before or after depositing the initiator, and annealing the substrate before or after forming the surface polymer.

[0082] In particular, at least one polymerization control agent as defined herein may be added before, during, or after surface polymer formation. However, other components of the reaction mixture, such as additional monomers, may also be provided during the course of surface polymer formation. In some embodiments, the reaction components may be adjusted to accommodate a subsequent substrate for surface polymer formation.

[0083] In one embodiment, an amount of oxygen control agent is added to the reaction composition to prevent the molecular O2 partial pressure in the solution from exceeding 25 hPa. The oxygen control agent may be added once or several times, depending on the measured molecular O2 partial pressure. For example, if additional molecular O2 is supplied over time from an external source, such as a molecular O2-containing atmosphere (ambient atmosphere), to consume the amount of oxygen control agent initially added, a spike (i.e., further addition) of oxygen control agent to the reaction composition may be performed to maintain a stable molecular O2 concentration in the solution corresponding to a partial pressure of molecular O2 that is less than the target molecular O2 partial pressure of 25 hPa defined herein. Evaluation of the conditions for such a spike may be based on continuous measurement of the concentration and / or partial pressure of dissolved molecular O2 in the reaction composition, such as with a dedicated oxygen sensor.

[0084] By adding / spiking additional oxygen control agent at a given time, the concentration of dissolved molecular O2 in the reaction composition can be maintained to extend the life of the reaction composition for surface polymer formation, thus allowing multiple surface polymer formation events in a sequential manner.

[0085] In one embodiment, the target range of pH values ​​"x" as defined herein (x > pK of the catalyst / ligand complex) a H1 or pK a H1>x>pKa A pH control agent is added to the reaction composition in an amount to achieve pH H2).

[0086] By adding / spiking additional pH control agent, the pH value of the reaction composition is maintained to extend the life of the reaction composition for surface polymer formation, thus allowing multiple surface polymer formation events in a sequential manner.

[0087] The phrase "at least one" as used throughout this disclosure herein is intended to include one or more components of the reaction mixture, polymerization control agent, substrate, or part of the extended substrate. There is no limit to the number of substrates as long as the reaction composition is active in forming a surface polymer.

[0088] Other parameters may be monitored to control the reaction composition and thereby the kinetics of surface polymer formation and adjusted accordingly, including, but not limited to, temperature, turbidity, conductivity, and chemical parameters measured, for example, by spectroscopy and spectrophotometry.

[0089] The reaction composition includes at least one solvent. The solvent can be any solvent that provides sufficient solubility of the components of the reaction composition. Suitable solvents include, but are not limited to, alcohols, dipolar aprotic solvents (e.g., tetrahydrofuran, methyl acetate, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethylformamide), methylene carbonate, ethylene carbonate, propylene carbonate, ethyl alcohol lactate, toluene ionic liquids, supercritical CO2, and water, and mixtures thereof.

[0090] Non-limiting examples of suitable monomer types include anionic, cationic, zwitterionic, protic, and aprotic monomers, including acrylates, methacrylates, halogen-substituted alkenes, acrylamides, methacrylamides, and styrenes, and mixtures thereof. A typical monomer structure includes a polymerizable moiety (an alkenyl group), which, in certain embodiments, is attached via specific linker chemistries to a functional group responsible for the specific functionality of the particular monomer (e.g., adhesion, permeability, electrical conductivity, and ionic conductivity).

[0091] For acrylate monomers, non-limiting examples of functional moieties include, but are not limited to, alkyl groups, sulfonates, fluorosulfonates, carboxyls, metal carboxylates, ethers, poly(ether) groups, bis(sulfonyl)amides, fluorinated sulfonates, perfluoroalkyl carboxylates, borates, fluorinated borates, borate ester derivatives, tetraphenylborate, bis(trifluoromethane)sulfonimides, triflimides and their derivatives, halogenated alkyl chains, and mono-, di-, and trialkoxysilanes.

[0092] The polymerizable portion and functional portion of the monomer may, in certain embodiments, be linked by a linker moiety. Non-limiting examples of suitable linker chemistries include, but are not limited to, alkyl chains, esters, ethers, poly(ethers), amines, amides, aryls, and any combination thereof. Non-limiting examples of suitable acrylate monomers containing alkyl linkers include, but are not limited to, methyl acrylate, ethyl acrylate, and lauryl acrylate. Non-limiting examples of monomers using ether and poly(ether) linker chemistries include, but are not limited to, poly(ethylene glycol) methyl ether acrylate and poly(ethylene glycol) acrylate. Non-limiting examples of monomers without linker chemistries include, but are not limited to, acrylic acid, lithium acrylate, and sodium acrylate.

[0093] For methacrylate monomers, non-limiting examples of suitable functional moieties include, but are not limited to, carboxylic acids, metal carboxylates, esters, alkyl alcohols, oxiranes, straight and branched chain alkyl groups, sulfonates, fluorosulfonates, bis(sulfonyl)-amides, fluorinated sulfonates, perfluoroalkyl carboxylates, borates, fluorinated borates, borate ester derivatives, tetraphenylborate, bis(trifluoromethane)sulfonimide, triflimide and its derivatives, halogenated alkyl chains, and mono-, di-, and trialkoxysilanes.

[0094] Non-limiting examples of linker chemistries include, but are not limited to, alkyl chains, esters, ethers, poly(ethers), amines, amides, aryls, and any combination thereof.

[0095] Non-limiting examples of methacrylate monomers include, but are not limited to, methacrylic acid, lithium methacrylate, sodium methacrylate, methyl methacrylate (MMA), potassium 3-sulfopropyl methacrylate, 2-hydroxyethyl methacrylate (HEMA), glycidyl methacrylate (GMA), ethyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, lauryl methacrylate, 4-methyl-3-oxopent-4-en-1-yl 1,1, Examples include 2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate and 3-(N-((trifluoromethyl)sulfonyl)sulfamoyl)propyl methacrylate, potassium 3-(meth-acryloyloxy)propane-1-sulfonate, 1H,1H,2H,2H-heptadecafluoro-decyl methacrylate (HFDMA), 2-((triethoxysilyl)oxy)ethyl methacrylate, and 2-(3-(triethyloxysilyl)propoxy)ethyl methacrylate.

[0096] Non-limiting examples of suitable halogen-substituted alkene monomers include, but are not limited to, vinyl chloride, vinylidene difluoride, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene.

[0097] Non-limiting examples of suitable acrylamide monomers include, but are not limited to, acrylamide, N-iso-propylacrylamide, N-tert-butylacrylamide, and N-hydroxyethylacrylamide.

[0098] Non-limiting examples of suitable methacrylamide monomers include, but are not limited to, N-iso-propyl methacrylamide, methacrylamide, N-tert-butyl methacrylate, and N-hydroxyethyl methacrylamide.

[0099] Non-limiting examples of suitable styrene monomers include, but are not limited to, styrene, 4-methylstyrene, 2,3,4,5,6-pentafluorostyrene, p-divinylbenzene, 4-chlorostyrene, sodium 4-vinylbenzenesulfonate, lithium 4-vinylbenzenesulfonate, and 4-vinylphenyl 1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate.

[0100] Monomers may be selected to provide conformability / adhesion / elasticity as appropriate for a particular application. Monomers may also be selected to enhance or decrease electrical and / or ionic conductivity and / or permeability. Monomers may be selected to improve interfacial stability of the surface in question.

[0101] The monomers may be suitably used in amounts corresponding to their proportion to the remaining components of the reaction medium, e.g., 0.5 to 50% by volume or 0.5 to 50% by weight. For example, liquid monomers may comprise, for example, 0.5%, 2%, or 10% by volume of the reaction composition. For example, solid monomers may comprise, for example, 0.5%, 2%, or 10% by weight of the reaction composition. For each application, the amount of monomer may be selected to provide the desired polymer formation kinetics, monomer solubility, and monomer cost.

[0102] As described above, the reactive compositions for forming surface polymers disclosed herein are viable for forming surface polymers over an extended period of time. Therefore, the reactive compositions can be reused to form surface polymers on several subsequent substrates or portions of a substrate. The extended period can preferably be up to six hours or more. Even more surprisingly, it has been shown that, using reactive compositions according to embodiments of the present disclosure, surface polymers can be formed on the surface of a substrate with a uniform thickness over an extended period of time. Thus, multiple substrates, or even elongated flexible substrates, can be subjected to surface polymer formation within the lifetime of the reactive composition. The number of substrates depends on the polymerization time and the lifetime of the reactive composition. For example, a substrate can be contacted with the reactive composition for 10 seconds to 60 minutes. Prior art techniques have not provided such reusable reactive compositions.

[0103] In certain embodiments of the present disclosure, the surface polymer is a polymer brush. Throughout this disclosure, the term "surface polymer" may also include polymer brushes.

[0104] According to one aspect of the present disclosure, a system for forming the aforementioned surface polymer on a polymerization initiator-modified substrate is provided. In other words, the substrate is treated with a polymerization initiator, thus forming polymerization initiation sites on at least a portion of the substrate. For example, the surface of the substrate on which it is desired to form the aforementioned surface polymer is subjected to polymerization initiator modification. The polymerization initiator enables the surface polymer to form on the substrate when the substrate is subsequently contacted with the aforementioned reactive composition. For the present purposes, it is not essential that the polymerization initiator be applied to the substrate, provided that this is done before contacting the substrate with the reactive composition. In some embodiments, it is contemplated that the substrate may be pre-coated with a polymerization initiator and provided to the system containing the polymerization initiator coating. In other embodiments, it is contemplated that application of the polymerization initiator coating may be performed within the system, and appropriate equipment may be provided to accomplish this, if necessary.

[0105] 7 is a non-limiting schematic diagram of a system 100 for forming a surface polymer on at least a portion of a substrate. The system 100 includes a reactant composition vessel 104 containing the aforementioned reactant composition 105. The vessel 104 may refer to any vessel or chamber suitable for holding a reactant composition. At least a portion of the polymerization initiator-modified substrate 102 is contacted with the reactant composition 105, for example, by at least partially immersing the desired surface of the substrate 102 in the reactant composition, thereby allowing a surface polymer to form on the substrate.

[0106] Optionally, system 100 may include one or more additional containers, each containing a different composition and / or agent for treating substrate 102 either before or after the substrate contacts reactive composition 105. If substrate 102 has not been pretreated with a polymerization initiator, system 100 may further include container 106 holding polymerization initiator chemical 107, thus forming initiator-modified substrate 102 within container 106.

[0107] FIG. 7 relates to an embodiment in which the substrate is precoated with a polymerization initiator. In such an embodiment, as shown in FIG. 7, a cleaning vessel 114 including a cleaning agent or cleaning device 116 may be provided. The cleaning agent / device 116 may be used to clean the surface of the substrate 102 before contacting it with the reactant composition 105 held by the reactant composition vessel 104. This may be achieved by subjecting at least a portion of the substrate 102, on which it is desired to form a surface polymer, to a cleaning procedure in the vessel 114 using the cleaning agent / device 116. In this manner, any impurities that may interfere with the formation of a surface polymer are removed from the surface of the substrate 102 before contacting the substrate 102 with the reactant composition 105. The system 100 may further include a substrate transfer device 103 for transporting the substrate 102 into at least partial contact with the reactant composition 105 held by the reactant composition vessel 104 for a controlled period of time to ensure that a surface polymer is formed. The transfer device 103 may be used to remove the substrate 102 from the reactant composition 105 after surface polymer formation. Thus, the substrate transfer device 103 may be configured to maintain the surface of the substrate 102 at least partially in contact with the reactive composition 105 and allow a surface polymer to form on at least a portion of the surface of the substrate, and the substrate transfer device 103 may be configured to maintain the substrate 102 in contact with the reactive composition 105 for a predetermined time.

[0108] In embodiments in which system 100 may include two or more containers, such as that shown in FIG. 7, in addition to contacting substrate 102 with the composition contained in each container, substrate transfer device 103 is configured to transport substrate 102 to and from each container. For example, as shown in FIG. 7, substrate transfer device 103 is configured to first transport substrate 102 to contact with cleaning agent / device 116 in container 114 and / or polymerization initiator composition 107 if the substrate has not been pre-coated with a polymerization initiator as described above and is held in polymerization initiator container 107, and then transport substrate 102 from polymerization initiator container 107 to reactant composition container 104, where the substrate is at least partially contacted with reactant composition 105 held by reactant composition container 104. In the latter example, embodiments may wash the substrate between initiator coating and surface polymer formation.

[0109] The substrate transfer device 103 may relate to any device capable of transporting a substrate from one container to another. For example, the substrate transfer device 103 may relate to a mechanical device. In particular, it is contemplated that the substrate transfer device 103 may comprise any one of the following: a conveyor system, a programmable mechanical arm, and / or a roll-to-roll processor / mechanism.

[0110] As used herein, a conveyor system, in embodiments, may refer to a mechanical system used to move materials, such as substrates, which may be in a substrate holder on their own or with other substrates, from one process vessel to another, and typically comprises a movable conveyor powered by a drive system and having a series of rollers or pulleys that support and guide a belt. In use, a substrate may be placed on the conveyor, which passes the substrate through one or more vessels included in the system. In this manner, as the conveyor is driven, the substrate passes through components held by each vessel in the system.

[0111] 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.

[0112] A roll-to-roll processor or mechanism is particularly advantageous for use when the substrate may be flexible and elongated, such as a cable, wire, foil, or any other elongated flexible substrate. Figure 8 shows such an embodiment in which the substrate transfer device is associated with a roll-to-roll processor 118 comprising an outgoing 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 allowing a flexible, elongated substrate 123 to be transferred from the outgoing roll 121 through the reactive composition 105 in the vessel 104 to the receiving roll 122. A roll-to-roll mechanism may be utilized as an alternative to the substrate transfer device 103 of Figure 7 when an elongated, flexible substrate is being processed.

[0113] In still further embodiments, at least one of the plurality of containers may include an annealing oven for annealing the formed surface polymer. In a similar manner as described above, the substrate transfer device 103 may be configured to transport the substrate with the formed surface polymer to the annealing oven 109 and move the substrate with the surface polymer into position for annealing. The annealing oven may include a heating device for annealing the formed surface polymer, and the gas environment 111 within the oven may be controlled, if necessary, to avoid oxidation, for example, by using only non-oxidizing gases.

[0114] FIG. 9 is a more detailed schematic diagram of a reactant composition vessel 104 containing the reactant composition 105 of FIG. 7 or FIG. 8 , according to one embodiment. The reactant composition vessel 104 may include one or more sensors. The one or more sensors may be configured to measure a property of the reactant composition 105, which may be related to a physical or chemical property of the reactant composition 105, such as the pH of the reactant composition or the molecular oxygen concentration in the reactant composition. The sensor data may be used to determine whether the value of the measured property is within a predetermined threshold for the surface polymer formation process. If the measured property is determined to be outside the predetermined threshold, the chemistry of the reactant composition may be adjusted by dispensing a polymerization control agent into the reactant composition to adjust the value of the measured property. In this manner, it is possible to ensure that the value of one or more properties of the reactant composition is within a range suitable for forming a surface polymer on a substrate. A control unit operably connected to the one or more sensors may be used to control one or more dispensers for dispensing one or more control agents to control the chemistry of the reactant composition; for example, an increase in pH may be corrected by dispensing an acid into the reactant composition 105 in the vessel 104. The measured property may relate to any one of the aforementioned physical or chemical properties of the reaction composition.

[0115] Similarly, the chemistry of the reaction composition can be adjusted by dispensing any one or more of the components of the reaction composition into the reaction composition. For example, the components can 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 can be configured to output a control signal for controlling the operation of a dispenser to dispense one or more components of the reaction composition into the reaction composition in response to a measured property of the reaction composition or in response to an observed variation in the property over time. For example, the value of the measured property can be monitored over a period of time using one or more sensors. The control unit can determine to output a control signal for controlling the operation of one or more dispensers to dispense one or more components based on the observed change in the measured property over time. The observed variation can indicate that the chemistry of the reaction composition is fluctuating, resulting in a surface polymer formation process that is out of specification, e.g., surface polymer formation is reduced and / or impaired. Distributing one or more components of the reaction composition throughout the reaction composition may help to maintain one or more chemical properties of the reaction composition to enable the formation of a surface polymer.

[0116] In some embodiments, dispensing of 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 that the chemical and / or physical properties of the reaction composition are as desired. However, dispensing of one or more control agents and / or components of the reaction composition, more specifically, the output of one or more control signals by the control unit for controlling the dispenser, may be independent of any particular sensor measurement. (The latter method of maintaining the reaction composition may be based, for example, on known consumption rates of the components of the reaction composition or known changes in pH or molecular oxygen concentration over time.) In still further embodiments, dispensing of one or more control agents and / or components of the reaction composition, more specifically, the output of one or more control signals by the control unit, may depend directly on one or more measured properties of the reaction composition. Similarly, the output of one or more control signals by the control unit for controlling dispensing of one or more control agents and / or components of the reaction composition may depend on measured sensor signals indicative of changes in the measured properties of the reaction composition. A combination of some of these different methods may also be advantageous, for example using the distribution of agents and / or components to maintain the reaction composition over shorter time intervals without using sensor measurements, in combination with adjustments made based on periodic sensor measurements made at longer time intervals.

[0117] For non-limiting purposes only, the examples shown in Figures 9-11 illustrate embodiments in which a control unit outputs one or more control signals for controlling one or more dispensers in response to a measured sensor signal indicating that a predetermined threshold related to a characteristic of the reactive composition has not been met.

[0118] 9, according to some embodiments, the reaction composition container 104 may include a pH sensor 216 operably coupled to the control unit 210. The pH sensor 216 may consist of a probe or electrode inserted into the reaction composition 105 to be measured. The pH sensor 216 and the control unit 210 may be used to determine whether the pH of the reaction composition 105 is within a range suitable for surface polymer formation. For example, the control unit 210 may be programmed to determine whether the pH value of the reaction composition measured by the pH sensor 216 is below a predetermined threshold below which surface polymer formation may still occur. In some embodiments, the pH threshold is determined by the pK a For example, in some embodiments, the predetermined pH threshold may be selected to be equal to or greater than the pK H value of the catalyst-ligand complex. a In yet further embodiments, the pH threshold may be related to a preferred range. For example, the pK a H1 or less, pK a H2 or higher.

[0119] The control unit 210 may be configured to control the operation of one or more chemical agent dispensers 202, 204. For example, one of the dispensers may be associated with a pH control agent dispenser 202 configured to dispense a volume of pH control agent 106 into the reaction composition 105. The control unit 210 may control the operation of the one or more dispensers 202, 204 via one or more output control signals. For example, the pH control agent dispenser 202 may be configured to dispense the pH control agent 206 into the reaction composition 105 in response to receiving a pH control signal from the control unit 210. The control unit 210 may be configured to output a pH control signal when a pH sensor signal is received by the control unit 210 indicating that the pH of the reaction composition 105 is below a predetermined threshold. Adding a pH control agent to the reaction composition 105 adjusts the pH of the reaction composition 105. In this manner, by adding a pH control agent to the reaction composition 105 as the pH changes relative to a threshold value, the pH of the reaction composition 105 can be controlled and ensured to remain in a range suitable for forming a surface polymer on the substrate 102 with the desired kinetics.

[0120] In some embodiments, the reaction composition container 104 may also include a molecular O sensor 218 operably coupled to the control unit 210. The molecular O sensor 216 may consist of a probe or electrode inserted into the reaction composition 105 to be measured. The molecular O sensor 218 and the control unit 210 may be configured to determine whether the molecular oxygen concentration of the reaction composition 105 exceeds a predetermined threshold. The predetermined threshold may be selected as a molecular oxygen concentration threshold above which the ability of the reaction composition 105 to form a surface polymer is impaired. For example, in some embodiments, the threshold may be 25 hPa or less. The molecular O sensor 218 may be operably coupled to the control unit 210 in a manner similar to the pH sensor 216. The control unit 210 may be configured to output an oxygen control signal to the oxygen control agent dispenser 204 when a molecular O sensor signal is received by the control unit 210 from the molecular O sensor 218 indicating that the molecular oxygen concentration of the reaction composition 105 is greater than the predetermined threshold. Dispensing an oxygen control agent, such as any one of those described herein (e.g., sodium ascorbate), into the reaction composition 105 serves to reduce the molecular oxygen concentration in the composition. By selectively dispensing an oxygen control agent into the reaction composition 105 when the molecular oxygen concentration exceeds a desired threshold, the molecular oxygen concentration of the reaction composition 105 can be maintained within a desired range, which promotes the formation of surface polymers and stable kinetics of surface polymer formation.

[0121] 9 , according to some embodiments, the reaction composition vessel 104 may include a recirculation circuit 211 that includes a pump or other device that provides efficient mixing of the reaction composition to help ensure that any dispensed control agent is more evenly distributed throughout the reaction composition 105 and around the substrate. In other embodiments, other mechanical or ultrasonic mixing may be applied. The recirculation circuit may include a filter to remove particles and bulk polymers, if present in the reaction composition; in other embodiments, the filter may be located in a portion of the vessel other than the recirculation circuit where there is good circulation of the reaction composition.

[0122] FIG. 10 is a process flowchart illustrating an exemplary method that may be performed by the control unit 210 of FIG. 9 according to one embodiment to control the operation of the pH control agent dispenser 202. At step 302, a pH sensor signal is received by the control unit 210. If, at step 304, it is determined that the pH sensor signal indicates that the pH of the reaction composition 105 is below a predetermined pH threshold, the control unit 210 generates and outputs a pH control agent dispenser trigger signal at step 306, as described above. This, in turn, causes the pH dispenser 202 to dispense a pH control agent into the reaction composition 105 at step 308. In some embodiments, it is contemplated that the control unit 210 may periodically receive the pH sensor signal. Thus, in such embodiments, if, at step 304, it is determined that the received pH sensor signal does not indicate that the pH of the reaction composition 105 is below the pH threshold, the control unit 210 simply waits for receipt of a pH sensor signal indicating that the pH is below the threshold to control the operation of the pH control agent dispenser 202.

[0123] Steps 302-308 may be repeated iteratively until the measured pH of the reaction composition 105 is equal to or greater than a predetermined pH threshold. For example, in certain embodiments, the pH control agent dispenser 202 may be configured to dispense a predetermined dose (e.g., volume) of pH control agent upon receiving a first control signal from the control unit 210. However, in some scenarios, multiple doses of pH control agent may be required to increase the pH of the reaction composition 105 above the pH threshold, in which case steps 302-308 may be repeated iteratively until a sufficient number of doses of pH control agent have been dispensed into the reaction composition 105 to reach or exceed the pH threshold.

[0124] 11 is a process flowchart illustrating an exemplary method that may be performed by the control unit 210 of FIG. 9 according to one embodiment to control the operation of the oxygen control agent dispenser 204. In step 402, an O sensor signal is received by the control unit 210. If, in step 404, it is determined that the received O sensor signal indicates that the molecular oxygen concentration of the reactive composition 105 is greater than a predetermined oxygen threshold, then, as previously described, the control unit 210 generates and outputs an oxygen control agent dispenser trigger signal (e.g., a second control signal) in step 406. This then causes the oxygen control agent dispenser 204 to dispense the oxygen control agent 208 into the reactive composition 105 in step 408. If, in step 404, it is determined that the molecular oxygen concentration does not exceed the predetermined threshold, then the control unit 210 simply waits for receipt of an O sensor signal indicating that the molecular oxygen concentration is greater than the predetermined threshold in order to control the operation of the oxygen control agent dispenser 204.

[0125] In a manner similar to that disclosed in connection with FIG. 10 , steps 402-408 may be repeated iteratively until the measured oxygen value of the reactive composition 105 is below a predetermined molecular oxygen concentration. In some embodiments, the oxygen control agent dispenser 204 may be configured to dispense a predetermined dose (e.g., volume) of the oxygen control agent 208. It is contemplated that in some scenarios, multiple doses of the oxygen control agent 208 may need to be dispensed to reduce the molecular oxygen concentration of the reactive composition 105 below a predetermined molecular oxygen concentration, in which case steps 402-408 may be repeated until a sufficient number of doses have been dispensed to reduce the molecular oxygen concentration of the reactive composition 105 below the predetermined molecular oxygen concentration. In some embodiments, the oxygen control agent dispenser 204 may be configured to dispense a predetermined dose of the oxygen control agent 208 into the reactive composition 105 at a predetermined time, for example, when a substrate contacts the reactive composition 105.

[0126] It is envisioned that in some embodiments, the control unit may be configured to output a dispenser control signal when the value of the associated measured property of the reactive composition approaches a predetermined threshold, thereby enabling the associated control agent to be dispensed into the reactive composition before the value of the associated property falls outside the predetermined threshold.

[0127] In some embodiments, the control agent dispenser can be configured to implement a variable dose regimen, for example, where the dose of control agent dispensed is proportional to a measurement of a property of the reactive composition.

[0128] 10 and 11 disclose embodiments in which the oxygen and pH characteristics of the reaction composition are monitored independently, it should be understood that multiple properties of the reaction composition can be monitored in combination. Furthermore, it should be understood that the distribution of a control agent into the reaction composition can affect more than one property of the reaction composition. For example, the distribution of an oxygen control agent can affect the pH of the composition; similarly, the distribution of a pH control agent can affect the molecular oxygen concentration of the reaction composition.

[0129] In some embodiments, it may be advantageous to control the environmental conditions under which the system is implemented, particularly the environmental conditions under which the surface polymer is formed. For example, this may help reduce contaminants and other impurities that contaminate the reaction composition and / or substrate. 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 the surface polymer. To achieve this, in some embodiments, the system may be implemented within an environmentally controlled chamber. For example, the aforementioned containers may be located within one or more environmentally controlled chambers. In some embodiments, all of the containers may be located within one or more chambers. In some embodiments, a subset of the containers may be located within one or more chambers. For example, in some embodiments, it is contemplated that the polymerization initiator container may be located within a chamber, while the reaction composition container may be located outside the chamber. Similarly, in some embodiments, cleaning of the substrate prior to polymerization initiator formation may also be performed within an environmentally controlled chamber, in which case it is contemplated that the associated cleaning agent container is also located within an environmentally controlled chamber.

[0130] While the system in Figure 7 is shown as including four vessels containing a reactant composition, a cleaning agent or cleaning device, an initiator chemical, and an annealing oven, it should be understood that the system may include any number of vessels greater or less than those shown containing multiple different components and / or agents for treating the substrate. In particular, it is contemplated that the system may include multiple vessels containing multiple cleaning agents. Similarly, the system may include one or more annealing vessels configured to anneal the substrate at different stages in its treatment, i.e., before deposition of the polymerization initiator, before surface polymer formation, and / or after surface polymer formation.

[0131] According to some embodiments, both the washing vessel and / or the annealing vessel may be configured to treat the substrate at different stages, including, for example, before or after application of a polymerization initiator, and before or after surface polymer formation.

[0132] FIG. 12 is an exemplary process flow chart illustrating various stages by which a substrate may be cleaned and / or annealed. The system may include an initial cleaning stage, in step 501, in which the substrate is cleaned by contacting it with a cleaning agent or cleaning device contained in a cleaning vessel, as previously described. Examples of cleaning agents include HF and piranha solution for chemically etching surface oxides and organic contaminants, organic solvents for removing organic contaminants, by-products, and residual process chemicals, and water, acids, and bases for removing inorganic contaminants, by-products, and residual process chemicals. Examples of cleaning devices include ovens and vacuum ovens for thermal cleaning, ultrasonic baths for ultrasonic cleaning, electrical cleaning devices, and spray cleaning devices. Following this, in step 503, a polymerization initiator may be applied to the portion of the substrate on which it is desired to form a surface polymer. This may be accomplished by contacting the portion of the substrate on which it is desired to form a surface polymer with a polymerization initiator, such as a vaporized initiator or a solution containing the initiator, as previously described. After the polymerization initiator is formed, the polymerization initiator-modified substrate may optionally be cleaned by contacting it with a cleaning agent in step 505 and / or may optionally be annealed in step 507. Annealing may be performed as described above. In step 509, a portion of the substrate on which it is desired to form a surface polymer may be contacted with a reactive composition to form a surface polymer on the desired portion of the substrate, as described above. After forming the surface polymer on the portion of the substrate, the substrate, and more specifically the formed surface polymer, may optionally be cleaned using a cleaning agent in step 511 and / or may optionally be annealed in step 513. Thus, a system configured to perform all of the steps in FIG. 12 may include multiple cleaning vessels, each containing a cleaning agent, and multiple annealing vessels equipped with annealing components / devices. Thus, it should be understood that the process of cleaning and / or annealing the substrate may occur before and / or after polymerization initiation and before and / or after surface polymer formation.

[0133] In still further embodiments, it is contemplated that the cleaning material may be applied to the desired portion of the substrate using an applicator, such as, but not limited to, a spray device. In such embodiments, it is contemplated that the substrate-moving device may be configured to simply move the substrate within range of the applicator so that the applicator can apply the cleaning material to the desired portion of the substrate. The applicator may be connected to a reservoir containing the cleaning material.

[0134] According to some embodiments, the system may include one or more additional containers containing compositions for forming one or more additional layers or blocks of surface polymer on the substrate. It is therefore envisioned that each layer or block of surface polymer formed on the substrate may be formed by contacting a desired portion of the substrate with a reaction composition containing a different monomer. In this manner, multiple layers of surface polymer may be formed. Different layers may be associated with the same surface polymer, in which case different containers may contain reaction compositions having the same monomer, or different layers may be associated with different surface polymers, in which case the reaction compositions held in the different containers contain different monomers from the first. In some embodiments, so-called random surface polymers may be formed. Random surface polymers may be formed by applying a reaction composition having multiple different monomers. Random surface polymers may be formed as either the first surface polymer layer or additional surface polymer layers.

[0135] Some embodiments may include a post-treatment vessel containing a post-treatment agent, and the substrate transfer device is configured to contact a desired portion of the substrate with the post-treatment agent. In some embodiments, the post-treatment may include post-treatment of the formed surface polymer to convert specific chemical functional groups in the surface polymer to other chemical functional groups or to crosslink chemical functional groups in the surface polymer to chemical functional groups in adjacent surface polymers. Examples of relevant chemical reactions in the post-treatment include deprotection of protected carboxylic acids, nucleophilic substitution, ring-opening reactions, and anion exchange. In other embodiments, the post-treatment may include injecting nanoparticles or microparticles into the surface polymer. The nanoparticles and microparticles may be inorganic species.

[0136] In some embodiments, the system can include a drying device configured to dry the substrate before or after contacting the substrate with the composition held in any one of the containers included in the system. Drying can be accomplished, for example, by blowing air or heating.

[0137] Some embodiments may include an etching reservoir containing an etching agent, and the substrate transfer device is configured to contact the desired portion of the substrate with the etching agent. In some embodiments, the etching may include an etching device for etching a pattern on the substrate. The etching may be suitably performed by plasma etching or HF etching.

[0138] In still further embodiments, the vessel included in the system may include one or more devices for performing measurements or metrology on the substrate, particularly on the formed surface polymer, before or after each step in the surface polymerization, including, but not limited to, any one or more of: measuring, removing, and analyzing by-products and / or reaction composition components; measuring the thickness of the formed surface polymer; and / or measuring the size of the particulate bulk polymer formed by filtering off the bulk polymer.

[0139] According to some embodiments, the reaction composition vessel may include one or more additional sensors configured to measure a property of any one of the following components of the reaction composition: solvent, monomer, ligand, catalyst, catalyst activator.

[0140] According to some embodiments, the system may include multiple reaction composition vessels configured in parallel so that multiple different substrates may be prepared in parallel with the surface polymer.

[0141] In some embodiments, the reaction composition vessel may include a recirculation device configured to circulate the components of the reaction composition, particularly during and / or after dispensing of one or more polymerization control agents. This may improve diffusion of the polymerization control agent within the reaction composition. See, e.g., recirculation circuit 211.

[0142] Further examples of sensors that may be provided in the reaction composition container include a conductivity measuring device, a turbidity measuring device, an electrochemical measuring device, and a potentiostatic device. Furthermore, the reaction composition container may further include any one or more of the following devices: an ultrasonic treatment device, a temperature control device, a UV light generating device, an inert atmosphere generating device, and an IR light generating device. Such devices may be useful for monitoring, controlling, and / or optimizing the formation of a surface polymer on a substrate. Furthermore, the reaction composition container may be configured with one or more dispensers configured to dispense any agent for replenishing the reagents in the reaction composition (e.g., monomers, ligands, catalysts, catalyst activators, and / or solvents). Such dispensers may, in some cases, include a mixing station for mixing any solutions before dispensing them into the container. One or more sensors may also be incorporated to measure different parameters.

[0143] One or more containers may be equipped with a sealing device (e.g., a lid) to reduce evaporation of the contained composition and / or to reduce possible interaction with the surrounding atmosphere. One or more containers may be equipped with a means for inert gas purging to reduce the risk of explosion or minimize interaction of the various compositions with the surrounding environment. The inert gas purging may be applied, for example, through a bubbler to increase the dew point.

[0144] Any one of the containers may include a sample port for withdrawing a sample of the composition held within the container for analysis using an external device.

[0145] Several methods for preparing substrates for surface polymer formation have been described in the art. A brief description of commonly used processes is provided herein. However, it should be understood that alternative processes may also be suitable and feasible within the context of the present disclosure.

[0146] Polymerization initiator attachment: First, a polymerization initiator is attached (“immobilized”) to the surface of the substrate on which the surface polymer is to be formed. The polymerization initiator is covalently bonded to the surface of the material (see, for example, WO 2014 / 0075695). Depending on the nature of the material and the characteristics of the surface polymer to be formed, the polymerization initiator may be provided with a predetermined surface chemistry to enable attachment to the surface of the material. Non-limiting examples of suitable chemistries for attaching the polymerization initiator to the treated surface include, but are not limited to, aryl diazonium salts, organosilanes, organothiols, organic phosphonic acids, organic phosphonates, catechols, iodonium salts, alkenes, alkynes, and sol-gel coatings. Surface-immobilized polymerization initiators can be prepared as multilayer or monolayer films. Monolayer films can be densely packed (complete monolayer coverage) or partially packed, covering all or only a portion of the available surface. The density of the initiator film determines the density of the subsequently formed surface polymer. Density will be understood by those skilled in the art as the percentage of available substrate area that is covered by polymerization initiator.

[0147] The attachment of a polymerization initiator typically follows a one-step or two-step process. The one-step process involves applying a benzyl halide (such as benzyl chloride) or secondary or tertiary halide moiety grafted onto the surface of a substrate by either diazonium or silane grafting. The benzyl halide and secondary and tertiary halide moieties act as polymerization initiators for the following surface-initiated polymerization. The two-step process typically involves applying a surface graft of an initial organic compound bearing a nucleophilic group, and in the second step, attaching an initiator moiety using the nucleophilic group. The nucleophilic group may include a hydroxyl group or an amine group. The nucleophilic group is then reacted with an electrophile to attach the initiator moiety and form a covalent bond between the two. The initiator group may be, for example, a benzyl halide and a tertiary halide moiety.

[0148] The attachment process is further described below: Silane grafting step 1: Initiators can be attached to surfaces in one step by silane grafting of trialkoxysilanes bearing benzyl halide or tertiary halide groups, which is typically done either by vapor deposition, in solution, spray coating, or paint-on coating.

[0149] Diazonium Grafting 1 step: Initiators can be attached to surfaces in one step by grafting an aryl diazonium salt with a benzyl halide group. Diazonium grafting is usually accomplished by electrochemically or chemically activating the aryl diazonium salt, or by allowing it to react spontaneously.

[0150] Diazonium Grafting 2 Steps: Another route to initiator attachment is via a two-step process. The first step is the grafting of an aryldiazonium salt or silane containing a nucleophilic group (alcohol or amine). In the second step, a nucleophilic acyl substitution reaction adds a halogen-containing group to give the attached polymerization initiator.

[0151] Other methods of immobilizing / attaching the initiator may be applied.

[0152] If only certain areas of the surface of a material are coated with the polymerization initiator, the areas where the initiator is not desired can be blocked, for example, chemically, by using a foil, seal or cover, by etching, or by being masked or protected.

[0153] Surface polymer formation: The surface polymer is then grown or formed from the surface-attached initiator upon contact with a defined reactive composition.

[0154] The thickness of the surface polymer can be 1 to 1,000 nm. The preferred thickness of the surface polymer, measured as the dry film thickness of the collapsed surface polymer, depends on the particular intended application and can be preferably 1 to 500, 1 to 250 nm, 5 to 100 nm, 120 to 250 nm, 10 to 80 nm, or 10 to 30 nm. The thickness refers to the dry film thickness of the formed surface polymer. The dry film thickness depends on the density (anchored points per area) of end-linked polymer chains and the length of the individual chains.

[0155] In certain embodiments, the surface polymer layer may have specific properties achieved by a block copolymer, a random polymer, or a binary blend polymer, where two or more dissimilar monomers are used to grow the surface polymer with different surface polymer structures. In such embodiments, the individual components (different monomers) of the block copolymer, random polymer, or binary blend polymer may contribute different properties, resulting in a surface polymer with a desired combination of properties.

[0156] Surface polymer layers can be applied or formed by repeating some of the steps described above to build a block copolymer. The same or different monomers can be applied as those used to form the previous layer. Forming additional layers of surface polymer can be repeated multiple times to obtain more complex or thicker surface polymers. Surface polymers can also be formed using two or more different monomers grown from one or different types of initiators, thereby forming random or mixed surface polymers, respectively. Thus, two or more functional groups (e.g., halogen atoms, hydroxyl groups, or amine groups) can be incorporated, resulting in surface polymers with a unique combination of properties, each unique to the individual monomer.

[0157] To form a surface polymer, the substrate and the reaction composition defined herein are typically kept in contact with each other for a suitable period (residence time), such as 0.1 seconds to 5 hours. Residence times include, but are not limited to, 1 second, 2 seconds, 30 seconds, 1 minute, 5 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours. Surface polymer formation can be carried out at ambient temperature (room temperature) or with cooling or heating. Suitable temperatures are from -20°C to 120°C, for example, room temperature (about 20°C) to 120°C. Specific temperatures include, but are not limited to, -20°C, 0°C, room temperature (about 20°C), 30°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, and the like. The residence time and the temperature during the residence time can be suitably computer-controlled. Other methods of adjusting residence time and temperature may be based on conditions within the compartment holding the reaction composition (bath conditions) and / or measurements.

[0158] Substrate for surface polymer formation: While a wide variety of different substrates are expected to be useful in connection with the present disclosure, a suitable substrate should provide a surface that allows, first, the attachment of a polymerization initiator and, second, the formation of a surface polymer from said initiator sites. Substrates include, but are not limited to, metals (such as aluminum, steel, nickel, gold, silver, platinum, chromium, copper, iron, and alloys), glass, carbon, graphite, graphene, carbon black, monoclay, ceramics, composites, plastics, and particles (such as silicon, metals, and metal alloys). Substrates may have any size, shape, and structure, including elongated structures, and may be in the form of flakes, threads, fibers, cables, wires, particles, nanoparticles, monolayers, and the like.

[0159] As used herein, the terms "a substrate" and "the substrate" are intended to include both single substrates and multiple substrates of any form and shape.

[0160] The surface polymer may be suitably formed on a portion of the substrate or on all available surfaces of the substrate. The surface polymer may be formed on the available surfaces simultaneously (e.g., in the case of a single piece substrate) or may be formed on the available surfaces in a continuous manner (e.g., in the case of fibers, threads, wires, etc.).

[0161] Aspects and embodiments of the present disclosure are further illustrated by the following non-limiting examples. [Example]

[0162] Throughout the examples, DI water refers to tap water deionized using deionization equipment installed at RadiSurf's site in Denmark (Silhorko with M22-F softening plant, RO B1-2 Reverse Osmosis plant, and Silex 2BS mixed bed plant). DI water has a conductivity of <0.5 μS, indicating ultra-pure quality with very low ion presence. DI water quality is checked at least weekly. DI water retains a conductivity of less than 0.5 μS and shows very low ion presence of less than 0.1 mg / L.

[0163] Example 1 Silicon wafer pre-cleaning This example describes the procedure for pre-cleaning substrates for surface polymer formation. The total number of substrates may vary depending on the subsequent application.

[0164] Silicon wafer substrates (r=5.08 cm, wafer quarter cut, test CZ-Si wafer, 4 inch, thickness=525±25 μm, (100), p-type (boron), purchased from MicroChemicals GmbH) were cleaned using the following method before further processing: The rack containing the substrates was placed in an aqueous ammonia solution (15% by volume DI water / 85% by volume ammonia, commercially available, 25% pa, cleaning solution from Chemsolute) and sonicated for 10 minutes. The substrates were then rinsed with DI water and sonicated in DI water for 10 minutes. The rack containing the substrates was then transferred to a 5% solution of ABC clean A200 (from ABC-Clean ApS) and sonicated for 10 minutes in a Bandelin Sonorex Super RK100 ultrasonicator (35 kHz ultrasonic frequency, 80 W nominal ultrasonic power). After this step, the substrates were flushed in DI water (conductivity <0.5 μS) and sonicated for 5 minutes in DI water using the aforementioned equipment. Finally, the substrates were rinsed with acetone (>99%, Chemsolute) and dried at room temperature.

[0165] Example 2 Chemical vapor deposition of (p-chloromethyl)phenyltrimethoxysilane This example illustrates a procedure for covalently attaching a polymerization initiator onto a substrate.

[0166] The silicon wafer substrate described in Example 1, cleaned as described in Example 1, was used for surface modification with (p-chloromethyl)phenyltrimethoxysilane (CPTMS) polymerization initiator using chemical vapor deposition.

[0167] The substrates were placed on a rack and placed in a vacuum oven (Faithful Vacuum Drying Oven-DZ-BCII) containing 16 vials of 100 μL of CPTMS (polymerization initiator liquid, commercially available, 95% grade from Gelest) at approximately 45 °C for 150 min. The gauge pressure was reduced to -1.0 bar, thereby evaporating the CPTMS, and the substrates were left for 150 min. The substrates were then removed and placed in an oven (Binder model FD 56) at approximately 80 °C for 5 min to anneal the silane layer. The surface modification was verified using water contact angle (WCA) analysis on a Kruss Mobile Surface Analyzer. The WCA values ​​for blank and CPTMS-modified Si are shown in Table 2. The increase in WCA from blank to CPTMS indicated successful modification. [Table 2]

[0168] Example 3 Preparation of reaction composition for forming surface polymer This example illustrates the preparation of a 1000 mL reaction composition for the method disclosed herein.

[0169] To a glass vessel (vessel A) was added 76 μL of tris[2-(dimethylamino)ethyl]amine (Me6TREN, ligand, commercially available, ≥98% grade, from Abcr or Alfa Aesar), 15.924 mL of DI water, and 324 mg / L of Cu(II) obtained from a solid copper source. 16 mL of catalyst solution was added, consisting of an additional 484 mL of DI water, 410 mL of ethanol (96% grade, from KiiltoClean), and 75 mL of methyl methacrylate monomer (MMA, 99% grade containing ≤30 ppm MEHQ, from Sigma-Aldrich). In a separate glass vessel (vessel B), 4000 mg of sodium ascorbate (catalyst activator, commercially available, ≥98% grade from Sigma-Aldrich) was dissolved in 15 mL of DI water. Immediately after dissolution, the contents of vessel B were mixed with vessel A. After 5 minutes, the liquid was used for surface polymerization.

[0170] The amounts specified herein total 1000 mL and can be scaled to accommodate preparation of smaller or larger volumes of reaction composition.

[0171] Example 4 Evaluation of surface polymer (polymer brush) formation ability (lifetime) on a range of substrates using the methods disclosed herein This example illustrates a procedure for evaluating the polymer brush-forming ability of a reaction composition over time, which serves as a reference in subsequent examples.

[0172] A silicon wafer substrate (same grade as described in Example 1) was pre-cleaned as described in Example 1, and a polymerization initiator was attached to the surface as described in Example 2. The reaction composition was prepared as described in Example 3.

[0173] The substrates were immersed in the reaction composition, each one at a time, in a sequential manner, according to the following procedure: At 0 minutes, defined as 5 minutes after the addition of the catalyst activator (NaAsc), the first substrate was immersed in the reaction composition for 10 minutes. At 10 minutes, the first substrate was removed, and without changing the reaction composition or adding additional components to the reaction composition, another substrate was immersed in the liquid for 10 minutes. This was repeated until a total of 12 substrates had been subjected to surface polymer (polymer brush) formation in a sequential / continuous manner, for 10 minutes each, over the course of 120 minutes.

[0174] In some cases, the pH of the reaction composition was measured using a pH meter (Metrohm 913 pH meter or Metrohm 914 pH / DO / Conductometer). In some cases, the partial pressure of dissolved oxygen in the reaction composition was monitored using an O2-selective sensor (Pyroscience FireSting-GO2). The partial pressure readout can be converted to dissolved molecular oxygen content (concentration) given in molar concentration using Henry's law, which relates partial pressure to the amount of dissolved gas. These calculations can include correction for temperature fluctuations, atmospheric pressure, solvent mixture, and / or ionic strength effects on the solubility of dissolved molecular oxygen, or any combination thereof.

[0175] After surface polymer formation, the substrates were washed collectively by sonicating for 5 minutes in DI water (same grade as in Example 1) followed by sonicating for 5 minutes in acetone (same grade as in Example 1). The substrates were allowed to dry in ambient air.

[0176] After washing and drying the surface-polymerized substrates, the dry film thickness of the formed (collapsed) surface polymer was analyzed using ellipsometry (JA Woollam M-2000 Ellipsometer). For each substrate, the average dry film thickness (in nm, obtained by averaging the results obtained from ellipsometry at 10 different points on the silicon wafer surface) of the surface polymer formed during 10 minutes of polymerization was plotted against the time (in minutes) the substrate was extracted from the reaction composition relative to the time of addition of the first substrate to the polymerization medium. In this manner, the polymer brush-forming ability of baths containing the reaction compositions was evaluated at 10-minute intervals throughout a 120-minute lifespan test. The "bath life" or lifetime of a given reaction composition is defined as the time during which the surface polymer can form with steady kinetics, i.e., the thickness of the surface polymer grown at 10-minute intervals is within + / - 20% of the average thickness obtained over the reaction's lifetime. Ellipsometry data for the reaction composition described in Example 3 are shown in Table 3. According to the classifications described herein, the bath life of this reaction composition was determined to be ≥ 120 minutes. [Table 3]

[0177] Example 5 Evaluation of Sodium Ascorbate as an Oxygen Control Agent and pH Control Agent in the Disclosed Reaction Compositions and Methods This example illustrates the ability of sodium ascorbate (NaAsc) to act as both an oxygen control agent and a pH control agent, and that controlled kinetics are provided throughout the bath life of the reaction composition under these conditions. Results are compared to standard ATRP conditions in which exposure to oxygen-containing environments is not permitted and pH control is not performed.

[0178] Silicon wafers were pre-cleaned as described in Example 1, and polymerization initiators were applied to the surfaces as described in Example 2. Catalyst solutions and reaction compositions were prepared as described in Example 3, using the amounts of components as listed in Table 4. pH and the partial pressure of dissolved oxygen in the reaction compositions were continuously monitored using a pH meter (Metrohm 913 pH meter or Metrohm 914 pH / DO / Conductometer) and an oxygen sensor (Pyroscience FireSting-GO2). [Table 4]

[0179] First, the concentration of dissolved molecular oxygen in conjunction with the addition of NaAsc to the reaction composition was evaluated (Figure 13). In a solution of 48.4 mL of DI water and 41 mL of ethanol (96%), the initial concentration of dissolved oxygen was set at approximately 190 hPa. Upon addition of NaAsc, the molecular oxygen concentration was found to decrease over several minutes, beginning immediately and eventually stabilizing after 15 minutes at approximately 25 hPa. Furthermore, the addition of 1.6 mL of catalyst solution 8 minutes after the initial NaAsc addition showed an immediate (within seconds) decrease in molecular oxygen concentration from 190 hPa to ≦1 hPa. Furthermore, it was noted that no change in molecular oxygen concentration occurred when the catalyst solution was added to a solution without sodium ascorbate; however, the subsequent addition of sodium ascorbate resulted in a decrease in molecular oxygen concentration to ≦1 hPa within seconds (Figure 13).

[0180] Therefore, we conclude that sodium ascorbate acts as an oxygen control agent, and its effectiveness is enhanced when a catalyst / ligand complex (copper with a ligand) is present. The catalyst does not act as an oxygen control agent by itself. However, the reduction of molecular oxygen by sodium ascorbate is catalyzed in the presence of the catalyst / ligand complex.

[0181] The ability to form surface polymers (polymer brushes) over time was also evaluated as described in Example 4 (Formation of Surface Polymers on Multiple Substrate Surfaces in a Continuous Manner) using the amounts of components listed in Table 4. The pH of the reaction composition and the partial pressure of molecular oxygen (O) dissolved in the reaction composition were continuously measured using a pH meter and an O sensor. The resulting polymer brush thickness, pH, and O partial pressure as a function of time are shown in Figure 14.

[0182] The addition of sodium ascorbate to the reaction composition rapidly reduced the dissolved oxygen partial pressure from approximately 225 hPa to <1 hPa. The oxygen partial pressure was maintained at <1 hPa throughout the 120-minute period evaluated here with a single addition of sodium ascorbate as an oxygen control agent. The pH of the reaction composition was stable near pH 8, demonstrating that sodium ascorbate also acts as a pH control agent, at least when used at this concentration. Furthermore, the use of sodium ascorbate at this concentration ensured controlled kinetics throughout the surface polymer formation.

[0183] The thickness of the surface polymer on the substrate was 62 nm + / - 10% over the 120 minute period tested. From these data it was concluded that the bath life obtained was ≥ 120 minutes.

[0184] In comparison, the bath life of a literature-reported aqueous ATRP experiment (https: / / pubs.rsc.org / en / content / articlelanding / 2004 / jm / b312513k / unauth) was evaluated using the same setup and approach as previously described in this example for polymerizing glycidyl methacrylate (GMA). A silicon wafer was precleaned as described in Example 1, and a polymerization initiator was attached to the surface as described in Example 2. Inhibitors were first removed from GMA by passing it through an Al2O3 column. GMA (75 mL), MeOH (60 mL), and DI water (15 mL) were then combined in a 250 mL blue-capped bottle, and the solution was purged with N2 for 15 minutes while stirring to remove oxygen from the solution. CuCl (546 mg), CuCl2 (59 mg), and the ligand bipyridine (2.12 g) were added to the solution, and the solution was purged with N2 for an additional 5 minutes while stirring. The solution was sonicated for 5 minutes to better dissolve the Cu salt. This is referred to as the polymerization solution. Meanwhile, a separate sealed reaction vessel contained a substrate holder containing one silicon wafer with the polymerization initiator attached, and was equipped with the pH meter and oxygen sensor described above. The reaction vessel was purged with N2 gas for 10 minutes to remove O2. To maintain an inert atmosphere, the polymerization solution was transferred from the blue-capped flask to the reaction vessel via a double-needle. The pH and oxygen partial pressure in the solution were continuously monitored throughout the reaction composition. After 30 minutes, the first substrate was removed by removing the lid while maintaining a N2 flow over the solution. Without changing or adding additional components to the reaction composition, another substrate was immersed in the liquid, and the vessel was resealed for 30 minutes. This was repeated until a total of four substrates had been subjected to surface polymer (polymer brush) formation in a sequential / continuous manner, each for 30 minutes, over the course of 120 minutes. Post-cleaning and film thickness measurements were performed as described in Example 4.

[0185] The pH in the reaction composition started at approximately pH 8.5, steadily increased to 11.2 in the first 20 min, and remained there until the experiment was terminated after 120 min (Figure 15). The partial pressure of dissolved O was <5 hPa throughout the experiment, reaching a maximum of 30 hPa, except for spikes observed especially when switching substrates. The dry film thickness was approximately 1.9 nm for all four substrates (Figure 15), corresponding to the thickness of the Si oxide combined with the initiator film. Therefore, when attempting to promote classical ATRP in a setup without strict oxygen control, it was concluded that surface polymer (brush) formation would not occur if neither pH nor oxygen control agents were added.

[0186] Example 6 Demonstration of oxygen control using oxygen control agents to extend bath life and form surface polymers on multiple substrates in a continuous (sequential) manner (methods disclosed herein) This example illustrates how the molecular oxygen concentration in the reaction composition can be controlled using an oxygen control agent, and how spiking additional oxygen control agent extends the bath life of the reaction composition and creates surface polymers on multiple substrates in a continuous (sequential) manner. Sodium ascorbate is used as the oxygen control agent. Sodium ascorbate is also used as a catalyst activator to activate / reduce copper in the copper-ligand complex, thereby enabling the formation of surface polymers.

[0187] Silicon wafers were precleaned as described in Example 1, and a polymerization initiator was applied to the surface as described in Example 2. The reaction composition was prepared as described in Example 3, except that only 2 mM sodium ascorbate was used. Two 1 mM portions were added at 0 and 50 minutes, respectively. The time course of the surface polymer (polymer brush) formation capability was evaluated as described in Example 4 (Formation of Polymer Brushes on Multiple Substrate Surfaces). The amount of molecular oxygen (O) dissolved in the reaction composition was continuously measured using an O sensor (Pyroscience FireSting-GO2). The resulting polymer brush thickness and O partial pressure as a function of time are shown in Figure 16. Upon addition of the first portion of sodium ascorbate to the reaction composition, the dissolved oxygen partial pressure rapidly decreased from approximately 240 hPa to <1 hPa. The oxygen partial pressure was maintained at <1 hPa for 30 minutes. Between 30 and 50 minutes after the first addition of sodium ascorbate, the O2 partial pressure increased to >100 hPa, indicating that the oxygen scavenging capacity of the reaction composition decreased after 30 minutes. Immediately after the addition of the second portion of 1 mM sodium ascorbate at 50 minutes, the amount of dissolved O2 was again estimated to be ≤1 hPa. This partial pressure was maintained for 50 to 90 minutes before being increased again to >100 hPa.

[0188] The knowledge gained from this study allowed us to define the time points for the spike (addition of portions of sodium ascorbate) of sodium ascorbate as an oxygen control agent to keep the amount of O in the solution constantly low in the described setup: following the procedure described above, except that sodium ascorbate (1 mM) was added three times in total at 20, 50, and 80 min, resulted in a reaction composition containing a stable low amount of O for the entire 120 min after the first addition to activate the catalyst, which was further able to promote surface polymer formation over the entire period (shown in Figure 17).

[0189] Because sodium ascorbate is consumed in the process involved in oxygen scavenging, these data show a direct correlation between the decrease in the amount of oxygen scavenger (sodium ascorbate) used and the increase over time in the amount of O2 dissolved in the reaction composition.

[0190] Dry film thickness showed a decrease in the ability of the reactive composition to form surface polymers as the molecular oxygen concentration increased. At molecular oxygen concentrations corresponding to partial pressures of >25 hPa, no surface polymers were formed. Therefore, the molecular oxygen concentration should be maintained below, or at least equal to, this limit to maintain the activity of the reactive composition over an extended time frame.

[0191] It was further shown that decreasing the concentration of sodium ascorbate reduced the bath life (lifespan) of the reaction composition compared to Example 5. With an initial loading of 1 mM sodium ascorbate (Figure 16), the O2 partial pressure was stable for 30 minutes, with polymerization halting after this period, whereas with an initial loading of 20.2 mM sodium ascorbate (Figure 14 from Example 5), the O2 partial pressure was stable at <1 hPa for at least 120 minutes, with 62 nm + / - 10% surface polymer formed throughout the 120 minutes.

[0192] These data demonstrate a direct correlation between the amount of dissolved O2 (oxygen partial pressure) in the reaction composition and the reaction composition's ability to form surface polymers. Specifically, controlling the partial pressure of dissolved oxygen to <25 hPa using an oxygen control agent can significantly extend the life of the reaction composition and further enable the continuous formation of surface polymers.

[0193] Example 7 Use of pH control agents for surface polymer formation and for maintaining bath life of the reaction composition This example demonstrates the utility of pH control agents to control the kinetics and formation of surface polymers.

[0194] Silicon wafer substrates were pre-cleaned as described in Example 1, and a polymerization initiator was deposited on the surface as described in Example 2. Reaction compositions were prepared as described in Example 3, with the amounts of each component as shown in Tables 5 and 6 below, except that pH control was achieved by replacing the DI water in the reaction composition with a pH buffer solution (pH control agent) or by acidifying by adding methanesulfonic acid (MSA, commercially available, ≥99.0% grade, from Sigma-Aldrich) in DI water to provide different pH values ​​for the reaction composition. [Table 5] [Table 6] *CHES buffers are Good's buffers.

[0195] For each of reaction compositions a–f (Tables 5 and 6), the use of a pH control agent to control the pH and polymer-forming ability of the reaction composition was investigated. These were then compared to a composition (composition g) prepared as described in Example 3 without the addition of a supplemental pH control agent. For each reaction composition a–g, a time-dependent evaluation of the polymer brush-forming ability was performed using continuous pH measurements performed with a pH meter (Metrohm 913 pH meter) immersed in the reaction composition throughout the reaction time, as described in Example 4. For reaction compositions e and g, O2 partial pressure measurements were performed with an oxygen sensor (Pyroscience FireSting-GO2). For each reaction composition, the dry film thickness and measured pH values ​​were plotted as a function of time (Figures 18 and 19).

[0196] Stable polymerization kinetics were obtained throughout the 2-hour bath life for all reaction compositions a-e and g, thus demonstrating the high kinetic stability provided by the use of pH control agents. It is noteworthy that in the reference system (g), sodium ascorbate acts as a buffer system (due to its high concentration) and maintains a pH of approximately 8, which would be expected given that sodium ascorbate functions as a pH control agent. Also, in reaction compositions e and g, the partial pressure of dissolved oxygen was approximately 0 hPa throughout the bath life. Considering that all reaction compositions have the same concentration of sodium ascorbate (O scavenger), the same low concentration of dissolved O is expected for reaction compositions a-d.

[0197] Using the buffer systems of reaction compositions a to d and g, respectively, the pH of the reaction compositions was adjusted to the pK a The pH value of H1 can be maintained above 8.1, which allows the kinetics of the surface polymer-forming activity of the reaction composition to be maintained at a high level. Thus, the reaction composition can accommodate multiple consecutive surface polymerization events. When 225 μL of MSA is added (composition e), pH=6 is higher than the pK value of the Cu / Me6TREN complex. a H1 and pK a The kinetics in this case is determined by the pH of the catalyst. <pK a Note that because it is H1, it is particularly slow due to protonation. Importantly, the reaction composition still accommodates multiple consecutive surface polymerization events. When 1300 μL of MSA is added (composition f), pH = 3.7 is below the pK of the Cu / Me6TREN complex. a The dry film thickness was approximately 1.9 nm for all substrates, corresponding to the thickness of the Si oxide combined with the initiator film. For reaction conditions e and f with the addition of MSA, an increase in the amount of bulk polymer formation was observed.

[0198] These findings demonstrate that different pH control agents can be used to control the pH level of the reaction composition and indicate the possibility of achieving stable surface polymer formation kinetics for at least 2 hours if the pH level is kept constant during this period.

[0199] Example 8 UV / Vis characterization and pK of copper / ligand complexes a H1 and pK a Determining the H2 value In this example, solutions of different copper / ligand complexes were analyzed by titration curves to determine the complex-specific pK a H1 and pK a Determine the H2 value.

[0200] UV / Vis spectroscopy (LLG-uniSPEC2 spectrophotometer) was performed on the catalyst solution prepared as described in Example 3, establishing a native pH of 11.8. The resulting UV / Vis spectrum was compared with that of a second solution containing CuCl2·2H2O (13.6 mg, ≥99.5% grade, from Sigma-Aldrich) in DI water (16 mL) without the ligand, and a third solution containing 76 μL of tris[2-(dimethylamino)ethyl]amine (Me6TREN, ligand, commercially available, from Abcr or Alfa Aesar, ≥98% grade) and DI water (15.924 mL) without the copper species. Figure 20 demonstrates that a species with a characteristic visible absorbance profile exists only when both copper and Me6TREN are present, and the absorbance profile matches literature values ​​for the Cu(II) / Me6TREN complex. Similar spectroscopic analyses can be performed on other copper-ligand complexes, if desired.

[0201] pK of a particular catalyst / ligand complex a H1 and pK a Establishing the H value can be performed by titration with acid or base. As an example, 16 mL of catalyst solution (described in Example 3) was added to a 20 mL glass vial equipped with a pH meter and a magnetic stir bar. Then, incremental addition of methanesulfonic acid (≥99% grade, from Sigma-Aldrich) was performed while stirring. By comparing the exact amount of acid added to the resulting solution pH, the pK a H1 and pK aH values ​​were obtained from the half-equivalent points (Figure 21). A similar methodology was used to determine the pK of different copper-ligand complexes. a H1 and pK a The specific pK values ​​of some of the copper / ligand complexes thus obtained can be used to determine H values. a H1 and pK a The H2 values ​​are disclosed in Table 7. [Table 7]

[0202] The pK thus obtained a H1 and pK a H2 allows defining the pH range suitable for surface polymer formation. For the specific complex Cu / Me6TREN (Figure 21), the pK a H1 = 8.4 (consistent with the literature, https: / / pubs.acs.org / doi / 10.1021 / acs.macromol.5b01454) and pK a H2 was found to be 4.1. Therefore, a high surface polymerization rate is expected at pH ≥ 8.4, a controlled surface polymerization rate is expected at 8.4 > pH > 4.1, and no effective surface polymerization rate is expected at pH ≤ 4.1.

[0203] Corresponding analyses of catalytic systems containing ligands other than Me6TREN can be performed similarly. As an example, for the specific complex Cu / PMDETA, the pK a H1=8.6 and pK a It was found that H2 = 3.4. Thus, at pH ≥ 8.6, a high surface polymerization rate is expected, at 8.6 > pH > 3.4, a controlled surface polymerization rate is expected, and at pH ≤ 3.4, no effective polymerization rate is expected. As another example, for the specific complex Cu / TREN, the pK a H1=9.4 and pK a It was found that H2 = 3.5. Therefore, at pH ≥ 9.4, a high polymerization rate is expected, at 9.4 > pH > 3.5, a controlled polymerization rate is expected, and at pH ≤ 3.5, no effective polymerization rate is expected.

[0204] Example 9 Formation of surface polymers (polymer brushes) in a sequential manner at different concentrations of oxygen control agents This example demonstrates the effect of sodium ascorbate catalyst activator concentration, which acts as an oxygen control agent, on the bath life of the reaction composition and its ability to form a surface polymer in a continuous manner. Different sodium ascorbate loadings (concentrations) were tested by varying the amount of sodium ascorbate dissolved in the added DI water ("Container B," see Example 3).

[0205] Steel and silicon wafer substrates were pre-cleaned as described in Example 1, and a polymerization initiator was deposited on the surface as described in Example 2. Reaction compositions A-F were prepared as described in Example 3, except that the sodium ascorbate loading was varied as defined below in Tables 9 and 10. Substrate handling and substrate numbers were as described in Example 4. [Table 8] [Table 9]

[0206] For each of reaction compositions A–F, evaluation of the ability to form surface polymer over time was performed as described in Example 4 (multiple surface polymer formation events). Figures 22 and 23 show the resulting dry surface polymer thickness as a function of time after activation of the reaction composition, and Figure 24 shows the pH of the reaction composition measured over time. From these data, it was concluded that the resulting bath life was 20 minutes (reaction composition A), 60 minutes (reaction composition B), 100 minutes (reaction composition C), ≥ 120 minutes (reaction compositions D–E), or 70 minutes (reaction composition F). These results suggest that the lower limit of sodium ascorbate concentration is at least 1.01 mM to ensure a bath life of at least 20 minutes, at least for the catalyst / ligand complex Cu / Me6TREN (reaction composition A). This result also suggests that the upper concentration limit of sodium ascorbate may depend on the solubility of the oxygen control agent / catalyst activator in the selected reaction composition. Indeed, high concentrations of sodium ascorbate can be used to ensure a pH > pK in the reaction composition. a A correlation was found between the length of bath life and the pH value of the reaction compositions: compositions C, D, and E, with bath lives ≥ 120 min, recorded very similar pH values ​​of 8.2-8.5 over time, all of which were within the pK range of the Cu / Me6TREN complex. a H1. In comparison, composition B, which has a bath life of 60 minutes, shows a decrease in pH value over time from 60 minutes onwards. Finally, composition A, which has a bath life of 20 minutes, shows a decrease in pH value over time from 20 minutes onwards. In both cases, the pH is determined by the pK a It has fallen below H1.

[0207] Furthermore, it has been demonstrated that one component, in this case sodium ascorbate, can function as both a catalyst activator and an oxygen control agent without adversely affecting catalyst activation or molecular oxygen concentration control. By initially controlling the concentration of sodium ascorbate in the reaction composition, the continuous formation of surface polymers with time intervals and stable kinetics for long-term use of the reaction composition can be controlled.

[0208] Example 10 Formation of surface polymers (polymer brushes) using various ligands This example demonstrates that the use of oxygen control agents is beneficial in different ligand systems. Other ligands (Table 11) were tested by replacing the Me6TREN-based catalyst solution ("Container A," see Example 3) with a stock solution (see Table 10 below) consisting of copper(II) chloride dihydrate and the ligand dissolved in DI water, keeping both the copper and ligand concentrations and molar ratios constant.

[0209] The Si substrates were pre-cleaned as described in Example 1, and a polymerization initiator was applied to the surface as described in Example 2. Reaction compositions 1-3 were prepared as described in Example 3, but using CuCl as the copper source and the ligands defined in Tables 11 and 12 below. In "Container B" (see Example 3), a mixture of 4.00 g (20.2 mM) sodium ascorbate dissolved in 15 mL of DI water was used for all ligands. [Table 10] [Table 11]

[0210] For each of reaction compositions 1-3, evaluation of the polymer brush formation ability over time was performed as described in Example 4. Figure 25 shows the resulting dry surface polymer thickness measured by ellipsometry (JA Woollam M-2000 Ellipsometer) as a function of time after activation of the reaction composition. From these data, it was concluded that the resulting bath lifetime was at least 120 minutes (the experiment was stopped at 120 minutes) using either Me6TREN (reaction composition 1), PMDETA (reaction composition 2), or TPMA (reaction composition 3) as the ligand. Therefore, all three ligand systems can be successfully used as ligands in the reaction compositions and methods disclosed herein, simultaneously using sodium ascorbate as a catalyst activator and oxygen control agent combination. Furthermore, pH and dissolved O2 partial pressure were continuously measured in the reaction compositions during these studies, shown in Figure 26, and in all cases showed stable pH and dissolved O2 partial pressures of approximately 0 hPa over time after addition of the activator. For Cu / TPMA as a catalyst / ligand complex, pH is the pK a For Cu / Me6TREN and Cu / PMDETA as catalyst / ligand complexes, the pH in solution is pK a Similar to H1. This means that pH ≥ pK a In H1, we emphasize that the reactive composition can be used to form surface polymers on multiple substrates with stable kinetics over long periods of time.

[0211] Example 11 Demonstration of the ability (longevity) to form surface polymers (polymer brushes) on a range of substrates using the reaction compositions disclosed herein in combination with buffers This example demonstrates the ability to tailor the buffered reaction composition (including monomers, solvent system, and Cu-based ligands) according to the specifications described herein to obtain a system with stable surface polymer formation capability over an extended time frame to produce specific surface polymers on a substrate.

[0212] Silicon wafer substrates (same grade as described in Example 1) were pre-cleaned as described in Example 1, and a polymerization initiator was deposited / bound onto the surface as described in Example 2. The reaction composition was prepared as described in Example 3, except that (1) 16 mL of catalyst solution was replaced with CuCl 2H O (13.6 mg), PMDETA (ligand, 60 μL), and DI water (16 mL), (2) 484 mL of DI water was replaced with glycine (buffer, 2807 mg), NaOH (pH control, 550 mg), and DI water (co-solvent, 374 mL), (3) 410 mL of ethanol was replaced with isopropanol (co-solvent, 537 mL), and (4) 75 mL of methyl methacrylate was replaced with tert-butyl methacrylate (monomer, 75 mL).

[0213] The ability to form surface polymer (polymer brush) over time was also evaluated using measurements of the pH of the reaction composition (Metrohm 913 pH meter) and the dissolved oxygen (Pyroscience FireSting-GO2) in the reaction composition, as described in Example 4. The thickness, pH, and O2 partial pressure of the resulting polymer brushes as a function of time are shown in Figure 27.

[0214] The dissolved oxygen concentration and pH of the reaction composition are demonstrated to be consistent throughout the 120 minutes over which measurements were taken. The surface polymer thickness on the substrate was 9.5 nm + / - 15% on each substrate throughout the 120 minutes tested. From these data, it was concluded that the resulting bath life was ≥ 120 minutes. Thus, when compared to, for example, the system described in Example 7, reaction composition a, it is demonstrated here that buffered reaction compositions exhibiting stable kinetics over extended periods of time can be obtained by varying both the solvent system, the ligand on Cu, and the monomer used.

[0215] Example 12 Effect of pH on the formation of surface polymers (polymer brushes) using pH control agents In this example, the dependence of surface polymerization on the pH of the reaction composition is demonstrated by using an acid additive as a pH control agent and evaluating the resulting surface and bulk polymer formation.

[0216] Silicon wafer substrates were precleaned as described in Example 1, and a polymerization initiator was deposited on the surface as described in Example 2. Reaction compositions I–VI were prepared as described in Example 3 (Cu / Me6TREN as the ligand), but with various amounts (Table 12) of methanesulfonic acid (MSA, commercially available, ≥99% grade, from Sigma-Aldrich) added: I: 0 μL (reference substrate), II: 50 μL, III: 110 μL, IV: 225 μL, V: 650 μL, and VI: 1300 μL. In this way, reaction compositions with different pH values ​​were obtained, allowing us to investigate the relationship between their surface polymer formation ability and their pH levels. For each reaction composition, the kinetics of surface polymer formation was evaluated by simultaneously immersing six initiator-deposited Si wafers into the reaction composition at time 0. Time 0 was defined as 5 min after the addition of the catalyst activator (NaAsc). After 2, 5, 7.5, 10, 20, and 40 minutes, the substrates were removed from the reaction composition and then washed by sonication in DI water for 5 minutes, followed by sonication in acetone for 5 minutes. The substrates were allowed to dry in ambient air before the dry film thickness of the formed (disintegrated) surface polymer was analyzed using ellipsometry (Table 12). [Table 12]

[0217] Immediately after application of each reaction composition for surface polymer formation as described, the reaction compositions were photographed to record the increasing extent of bulk polymer formation over time at lower pH values ​​(Figure 28). As a reference, reaction composition A (Figure 28A) without added MSA maintained transparency throughout the 40 minutes during which surface polymer formation was occurring, thereby indicating a low degree of bulk polymerization. Reaction composition B (Figure 28B) similarly maintained transparency. However, reaction compositions C (Figure 28C)-F (Figure 28D), representative of compositions D, E, and F, were completely opaque or highly turbid after 40 minutes of surface polymer formation. It was concluded that the rate of bulk polymer formation depended on the pH value of the reaction composition. This finding supports the proposal that at lower pH, the concentration of HO increases, and its effect is to increase the rate of bulk polymer formation.

[0218] Figure 29 shows the polymer film thickness as a function of surface polymer formation time for reaction compositions A through F. The corresponding pH values ​​can be seen in Figure 30. These data show that the ability of the reaction compositions to form surface polymers is highly dependent on the pH value.

[0219] Polymerization at pH ≥ 8 (reaction compositions A and B) resulted in a high degree of surface polymer formation at a high rate of surface polymer formation.

[0220] In comparison, polymerization at pH 7, 6, or 5 (reaction compositions C, D, and E, respectively) gradually reduced the extent of surface polymer formation.

[0221] At pH 4 (reaction composition F), a small amount of surface polymer was formed. Therefore, the Cu / Me6TREN complex was <pK a H2 was unable to catalyze surface polymer formation at pH < 4, which corresponds to

[0222] These findings suggest that the Cu / Me6TREN complex <pK aH1 is less efficient (but still retains activity) and pH <pK a Furthermore, these studies demonstrate the ability to control the rate of surface polymer formation by determining and maintaining a specific pH of the surface polymer-forming reaction composition, with fast polymerization rates occurring at a constant pH >pK. a This can be accommodated by maintaining H1, while a slow polymerization rate can be accommodated by maintaining pK a H1 and pK a This can be accommodated by maintaining a constant pH between H2 and H2. Both scenarios can be very beneficial depending on the specific application. The limitation of this method is the pH <pK a The absence of surface polymer formation in H2 and the relatively low pK a A catalyst / ligand complex with H2 should be used.

[0223] Example 13 Procedure for evaluating the ability of poly(styrene) surfaces to form polymer (polymer brush) This example illustrates a procedure for evaluating the ability of a reactive composition to form surface polymer poly(styrene) polymer brushes over time. This procedure serves as a reference in subsequent examples.

[0224] Silicon wafer substrates (same grade as described in Example 1) were pre-cleaned as described in Example 1 and polymerization initiators were attached / bonded to the surface as described in Example 2.

[0225] The pH control agent used in the polymer brush formation process was made by dissolving 6.020 g of glycine and 2.050 g of sodium hydroxide (NaOH, commercially available from Geyer GmbH & Co. KG) in 1 L of DI water (measured pH=10.06).

[0226] The polymer brush-forming solution was prepared as follows: In a container (Container A), 30 mL of catalyst solution (described in Example 3), 450 mL of glycine buffer, 10 mL of DI water, 480 mL of styrene monomer (commercially available from Merck Life Science ApS, grade ≥ 99.9%), and 20 mL of styrene monomer were added. In a separate container (Container B), 4.00 g of sodium ascorbate catalyst activator was dissolved in 15 mL of DI water. The contents of Container B were mixed with Container A. A silicon wafer substrate with polymerization initiator was placed in a 1200 mL reaction vessel. After 5 minutes, the liquid was ready for surface polymerization and poured into the 1200 mL reaction vessel.

[0227] After surface polymer formation, the substrates were washed collectively by sonicating for 5 minutes in DI water (similar grade as in Example 1), followed by sonicating for 5 minutes in acetone (having the specifications described in Example 1), followed by sonicating for 5 minutes in dichloromethane (DCM, 99.9% grade, from Chemsolute). The substrates were allowed to dry in ambient air. The thickness of the inner layer was analyzed by ellipsometry, as described in Example 4 (Formation of Surface Polymer on Multiple Substrate Surfaces in a Continuous Manner). The pH of the reaction composition was continuously measured with a pH meter. The resulting polymer brush thickness and pH concentration as a function of time are shown in Figure 31.

[0228] Example 14 Evaluation of the ability to form surface block copolymers (block copolymer brushes) on a range of substrates using the methods disclosed herein.

[0229] This example illustrates the procedure for evaluating the ability of block copolymer brushes to be formed. A silicon wafer substrate (same grade as described in Example 1) was precleaned as described in Example 1, and a polymerization initiator was attached / bonded onto the surface as described in Example 2. A reaction composition for forming an inner layer made of polymethyl methacrylate (MMA) was prepared as described in Example 7 using reaction composition c listed in Table 13. 58.601 g of sodium chloride (NaCl, commercially available from Chemsolute, 99.0% grade) was added to ensure the ability of block copolymer brushes to be formed. A reaction composition for forming an outer layer (block layer) made of polystyrene (PST) was prepared as described in Example 13.

[0230] The pH control agent used in the block copolymer brush formation process was made by dissolving 6.020 g of glycine and 2.050 g of sodium hydroxide (NaOH) in 1 L of DI water (measured pH=10.06).

[0231] The inner layer-forming reaction composition was poured into a reaction chamber containing 14 silicon wafer substrates with polymerization initiators attached, placed in a rack. The substrates were allowed to react for 20 minutes (to form a surface polymer). After surface polymerization, the substrates were collectively washed by sonication in DI water (same grade as in Example 1) for 5 minutes, followed by sonication in acetone (having the specifications described in Example 1) for 5 minutes, and then by sonication in DCM for 5 minutes. The substrates were allowed to dry in ambient air. The inner layer thickness was analyzed by ellipsometry using the apparatus described in Example 4.

[0232] The block layer-forming reaction composition was poured into a reaction chamber containing 14 silicon wafer substrates with PMMA polymer brushes placed in a rack. The substrates were allowed to react for 30 minutes. After surface polymer formation, the substrates were washed and analyzed as described above. The results are reported in Table 13. [Table 13]

[0233] The degrafting reaction composition contained 1.408 g of tetrabutylammonium fluoride (commercially available from Sigma-Aldrich, 98.2% grade) dissolved in 100 mL of DCM. Degrafting was initiated by pouring the reaction composition into a reaction chamber (20 × 30 × 6 cm) containing 14 substrates with PMMA-b-PST polymer brushes placed horizontally, coated side up, at the bottom of the reaction chamber. The reaction chamber was sealed with a lid and left on a laboratory stirring table (50 rpm) for 22 h.

[0234] After degrafting, the degrafting solution was collected and each silicon wafer was rinsed in DCM. The DCM used for rinsing was collected together with the degrafting reaction mixture in the flask. The combined degrafted composition and DCM were reduced by flushing the headspace with N2 gas to give a yellow oil.

[0235] The yellow oil was added dropwise to 40 mL of cold methanol (stored at -18°C, commercially available from Chemsolute, 99.85% grade) in a 50 mL centrifuge tube and centrifuged (3900 rpm, 5 minutes). After centrifugation, the centrifuge tube was decanted and the pellet was collected. The pellet was dissolved in DCM, and the liquid was added dropwise to 40 mL of cold methanol in a 50 mL centrifuge tube and centrifuged (3900 rpm, 5 minutes). The collected pellet was measured using IR. Comparison of the degrafted PMMA-b-PST (Figure 32, top) with the PMMA (ALTUGLAS™ VM, commercially available from Resinex) and PST (MW approximately 192,000 Da, commercially available from Sigma Aldrich, product number 430102) reference spectra (Figure 32, center and bottom, respectively) confirmed that the degrafted PMMA-b-PST characteristically exhibited features from both polymer types: IR analysis indicated the presence of PMMA structures at 1727, 1485, 1437, 1390, 1275, 1243, 1191, and 1144 cm -1 The presence of PST structure is confirmed by the stretching of 1604, 1497, and 1453 cm -1 This is confirmed by stretching, and the block structure is confirmed.

[0236] Example 15 Demonstration of oxygen control and surface polymer formation using sodium dithionite as an oxygen control agent to form surface polymers on multiple substrates in a continuous (sequential) manner (methods disclosed herein) This example confirms the ability to use other oxygen control agents to accommodate surface polymer formation as described herein. Sodium dithionite is a reagent that can rapidly scavenge oxygen in aqueous solutions. Due to its inherent reactivity with water as well as oxygen, this reagent is consumed at a higher rate than sodium ascorbate, meaning that a stable, low concentration of dissolved oxygen in aqueous solutions requires multiple additions of sodium dithionite over an extended period of time. Here, it is demonstrated that the sequential addition of sodium dithionite makes it possible to obtain a reaction composition that exhibits an extended bath life, accommodating several successive polymerizations of individual substrates.

[0237] Silicon wafer substrates (same grade as described in Example 1) were precleaned as described in Example 1. They were functionalized by vapor deposition of 3-aminopropyltrimethoxysilane (APTMS) by placing them in a desiccator containing 6 × 100 μL of APTMS in small glass vials. The chamber was evacuated using a vacuum pump for 5 minutes, and then the desiccator chamber was closed and left at room temperature. After 1 hour, the pressure in the desiccator was equalized, and the substrates were placed in an oven set at 100 °C for 1 hour. The APTMS-coated substrates were further functionalized to load the initiator for surface polymerization by immersion in a glass vessel containing α-bromoisobutyryl bromide (BIBB) (174 mL, 98% grade, from Sigma-Aldrich), triethylamine (20 mL, ≥98% grade, from Sigma-Aldrich), and dichloromethane (2610 mL, 99.9% grade, from Chemsolute). The reaction medium was placed on a shaking table set at 50 RPM for 1 hour. The substrates were then flushed with dichloromethane, sonicated in dichloromethane for 5 minutes, and sonicated in acetone for 10 minutes. These APTMS-BIBB-coated substrates were dried under a stream of argon before proceeding with the surface polymeric modification process, as described below.

[0238] To a glass vessel (vessel A) equipped with a lid, a pH meter (Metrohm 913 pH meter), and an O sensor (Pyroscience FireSting-GO2) was added 16 mL of catalyst solution (prepared as described in Example 3), a solvent mixture consisting of a 0.1 M solution of glycine (99.5% grade, from Chemsolute, 7.5 g / L) and EtOH (96% grade, from Kiiltoclean, 8 mL, 96%) in DI water (500 mL), and 75 mL of methyl methacrylate monomer (99% grade containing ≦30 ppm MEHQ, from Sigma-Aldrich). In each of three separate glass vessels (vessels B1, B2, and B3), sodium dithionite (≧85% grade, from Merck, 17.5 g) in DI water (10 mL) was mixed. The contents of Container B1 were added to Container A at this time point (defined as 0 minutes), and the first substrate was added to Container A. At 20 minutes, the first substrate was withdrawn from the reaction composition in Container A. At 40 minutes, the contents of Container B2 and the second substrate were added to Container A. The oxygen sensor was quickly removed from the reaction composition and then re-immersed to verify the O2 reading, and a spike in the oxygen reading was observed. At 60 minutes, the second substrate was withdrawn from the reaction composition in Container A. At 80 minutes, the contents of Container B3 and the third substrate were added to Container A. At 100 minutes, the third substrate was withdrawn from the reaction composition in Container A. The substrates were washed and analyzed as described in Example 4. The ellipsometry data, O2 readings, and pH readings are shown in Figure 33. The ellipsometry data are further shown in Table 14. [Table 14]

[0239] These results demonstrate that the bath life of the reaction compositions described herein was ≥ 100 minutes. Furthermore, the results demonstrate that the methods described herein can promote surface polymer formation using oxygen control agents with different specifications as described herein. [Explanation of symbols]

[0240] 100 systems 102 Base material 103 Substrate transfer device 104 Reaction composition container 105 Reaction Composition 106 Polymerization initiator chemical container 107 Polymerization initiator chemicals 109 Annealing Oven 111 Oven Gas 114 Detergent container 116 Cleaning Agent 118 Roll-to-Roll Processor 120 Laura 121 Sending Roll 122 Receiving Roll 123 Flexible, elongated substrate 202 Dispenser 204 Dispenser 206 pH control agent 208 O2 Control Agent 210 Control Unit 216 pH sensor 218 O2 sensor 211 Recirculation circuit 302 Process flow for controlling pH control agent dispensers 304 Process flow for controlling pH control agent dispensers 306 Process flow for controlling pH control agent dispensers 308 Process flow for controlling pH control agent dispensers 402 Process flow steps for controlling molecular oxygen control agent dispensers 404 Process flow steps for controlling molecular oxygen control agent dispensers 406 Process flow for controlling molecular oxygen control agent dispensers 408 Process flow for controlling molecular oxygen control agent dispensers 501 Cleaning step in exemplary surface polymer formation flow 503 Annealing step in exemplary surface polymer formation flow 505 Cleaning step in exemplary surface polymer formation flow 507 Annealing step in exemplary surface polymer formation flow 509 Formation process in exemplary surface polymer formation flow 511 Cleaning step in exemplary surface polymer formation flow 513 Annealing step in exemplary surface polymer formation flow

Claims

1. 1. A reaction composition for forming a surface polymer, comprising: at least one monomer; at least one ligand and at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; at least one solvent; and at least one polymerization control agent.

2. 10. The reaction composition of claim 1, wherein the at least one polymerization control agent is at least one pH control agent for controlling the pH of the reaction composition during surface polymer formation.

3. The at least one pH control agent adjusts the pH of the reaction composition to a value below the pK of the complex formed between the at least one catalyst and the at least one ligand. ａ 3. The reaction composition of claim 1 or 2, wherein the temperature is maintained above H.

4. The at least one pH control agent adjusts the pH of the reaction composition to the pK of the complex formed between the at least one catalyst and the at least one ligand. ａ H １ 4. The reaction composition of claim 3, wherein the reaction temperature is maintained above 100°C.

5. The at least one pH control agent adjusts the pH of the reaction composition to the pK of the complex formed between the at least one catalyst and the at least one ligand. ａ H ２ 4. The reaction composition of claim 3, wherein the reaction temperature is maintained above 100°C.

6. The at least one pH control agent adjusts the pH of the reaction composition to a value below the pK of the complex formed between the at least one catalyst and the at least one ligand. ａ H １ and pK ａ H ２ The reaction composition of claim 3, wherein the reaction composition is maintained between

7. The reaction composition of any one of claims 1 to 6, wherein the at least one pH control agent is a buffering agent.

8. The reaction composition of any one of claims 1 to 6, wherein the at least one pH control agent is an acid or a base.

9. 10. The reactive composition of claim 1, wherein said polymerization control agent is at least one oxygen control agent for controlling molecular oxygen concentration in said reactive composition.

10. 10. The reactive composition of claim 9, wherein the at least one oxygen control agent maintains a molecular oxygen concentration in the reactive composition at a partial pressure of less than 25 hPa.

11. 11. The reactive composition of claim 9 or 10, wherein the at least one oxygen control agent is an oxygen scavenger.

12. 10. The reaction composition of claim 1, wherein the at least one polymerization control agent comprises a pH control agent for controlling the pH of the reaction composition during surface polymer formation and an oxygen control agent for controlling the molecular oxygen concentration in the reaction composition during surface polymer formation.

13. 1. A reaction composition for forming a surface polymer, comprising: A solvent; A monomer, a catalyst and a ligand, wherein the at least one catalyst and the at least one ligand form a complex; The reaction composition wherein the polymerization control agent is a pH control agent, or a pH control agent and an oxygen control agent.

14. 1. A method for forming a surface polymer, comprising: contacting at least a portion of the polymerization initiator-modified substrate with a reactive composition, the reactive composition comprising: at least one monomer; at least one ligand and at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; at least one solvent; controlling the surface polymerization by the pH of the reaction composition and / or the molecular oxygen concentration of the reaction composition; and optionally adding at least one polymerization control agent to adjust the pH of said reaction composition and / or the molecular oxygen concentration of said reaction composition.

15. 15. The method of claim 14, wherein the at least one polymerization control agent is added at least once during or before the surface polymer formation.

16. the at least one polymerization control agent (i) at least one pH control agent; (ii) at least one oxygen control agent; or 16. The method of claim 14 or 15, wherein (iii) at least one pH control agent and at least one oxygen control agent.

17. 15. The method of claim 14, wherein the at least one polymerization control agent functions as a pH control agent and an oxygen control agent.

18. 1. A method for forming a surface polymer, comprising: providing a reaction composition, the reaction composition comprising: at least one monomer; at least one ligand and at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; at least one solvent; the reaction composition is held in a reaction composition container; contacting at least a portion of a first polymerization initiator-modified substrate with the reactive composition in the reactive composition vessel, thereby forming a surface polymer on the first substrate; removing the first substrate from the reaction composition in the reaction composition container; subsequent to removing the first substrate, contacting at least a portion of a second polymerization initiator-modified substrate with the reactive composition in the reactive composition vessel, thereby forming a surface polymer on the second substrate; removing the second substrate from the reaction composition in the reaction composition container; The method wherein the pH and / or molecular oxygen concentration in said reaction composition is optionally controlled by at least one polymerization control agent.

19. 20. The method of claim 18, wherein the reaction composition is modified during the surface polymer formation by adding additional components of the reaction composition and / or removing bulk polymer by-products.

20. 20. The method of claim 18 or 19, wherein the pH of the reaction composition and / or the molecular oxygen concentration of the reaction composition are controlled by measuring the pH and / or the molecular oxygen concentration during surface polymer formation in combination with the supply of at least one polymerization control agent.

21. The method of any one of claims 18 to 20, wherein a plurality of substrates are subjected to surface polymer formation in the reaction composition vessel in a sequential manner.

22. The method of any one of claims 18 to 21, wherein the pH of the reaction composition is adjusted to control the kinetics of the surface polymer formation.

23. 1. A system for forming a surface polymer on a substrate, comprising: A reaction composition vessel containing a reaction composition, the reaction composition comprising: at least one monomer; at least one ligand and at least one catalyst, wherein the at least one ligand and the at least one catalyst form a complex; at least one catalyst activator; a reaction composition vessel containing at least one solvent; a substrate transfer device for contacting at least a portion of a polymerization initiator-modified substrate with the reactive composition in the reactive composition vessel for a controlled period of time; The controlled time period is sufficient to form a surface polymer on the portion of the polymerization initiator-modified substrate.

24. the substrate transfer device Conveyor systems, a programmable mechanical arm, or 24. The system of claim 23, comprising any one of a roll-to-roll mechanism.

25. one or more sensors, each sensor configured to measure a different value of the property of the reaction composition; one or more dispensers configured to dispense one or more polymerization control agents and / or one or more components of the reaction composition into the reaction composition; a control unit operably connected to the one or more sensors; 25. The system of claim 23 or 24, wherein the control unit is configured to output control signals to the dispenser to dispense the one or more polymerization control agents and / or the one or more components of the reaction composition into the reaction composition.

26. 26. The system of claim 25, wherein the control unit is configured to periodically output the control signal to the dispenser, causing the dispenser to periodically dispense the polymerization control agent and / or components of the reactant composition into the reactant composition.

27. 26. The system of claim 25, wherein the control unit is configured to output the control signal in response to receiving a sensor signal indicative of a change in a value of the property of the reactant composition, or in response to receiving a sensor signal indicative of a measured value of the property of the reactant composition that does not meet a predetermined threshold value for the property of the reactant composition.

28. 28. The system of claim 27, wherein the predetermined threshold is a pH value and / or a molecular oxygen concentration.

29. The system of any one of claims 23 to 28, wherein a pH control agent and / or an oxygen control agent is dispensed into the reaction composition.

30. 30. The system of any one of claims 23-29, wherein the components of the reaction composition include 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.

31. 31. The system of any one of claims 23 to 30, further comprising a polymerization initiator container containing a polymerization initiator, wherein the substrate transfer device is configured to contact the portion of the substrate to which a polymerization initiator is to be attached with the polymerization initiator to form a polymerization initiator on the substrate surface before contacting the portion of the polymerization initiator-modified substrate with the reaction composition.

32. a cleaning vessel containing a cleaning agent, the substrate transfer device being configured to contact the portion of the polymerization initiator-modified substrate with the cleaning agent before or after contacting the portion of the polymerization initiator-modified substrate with the reaction composition; or 32. The system of any one of claims 23 to 31, wherein the substrate moving device is configured to contact the portion of the substrate with the cleaning material before or after contacting the portion of the substrate with the polymerization initiator.

33. 33. The system of any one of claims 23 to 32, comprising an annealing vessel containing an annealing agent, wherein the substrate transfer device is configured to contact the portion of the substrate with the annealing agent before or after contacting the portion of the substrate with the polymerization initiator or before or after contacting the portion of the substrate with the reaction composition.

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