Catalyst system for photo-induced atom transfer radical polymerization and application thereof

Abstract

The invention relates to the technical field of free radical polymerization, in particular to a catalyst system for photo-induced atom transfer radical polymerization and application of the catalyst system. A catalyst system for light-induced atom transfer radical polymerization comprising: (a) copper bromide; and (b) a mixed ligand composed of a first ligand and a second ligand, wherein the first ligand is Me < 6 >-TREN; and the second ligand is one or more than two micromolecule amines selected from ammonia water, piperidine and derivatives thereof, piperazine and derivatives thereof, piperazinone and derivatives thereof, morpholine and derivatives thereof, and tetramethylethylenediamine. According to the invention, trace Me6-TREN is compounded with excessive and cheap chain-shaped or cyclic micromolecule amine, so that a remarkable synergistic interaction effect can be generated, the Me6-TREN shows the same excellent performance as that of single use of the Me6-TREN, and the use cost of the Me6-TREN is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of free radical polymerization technology, and in particular to a catalyst system for photoinduced atom transfer radical polymerization and its application. Background Technology

[0002] Polymer brushes are a special type of polymer film, a polymer aggregation morphology formed by covalently grafting polymer chains onto a solid interface. Depending on the density and molecular weight of the grafted polymer chains on the solid surface, various conformations can be observed: at low grafting densities, a "mushroom-like" or "pancake-like" polymer conformation is formed, while at high densities, a brush-like conformation is formed. Surface modification strategies involving grafting polymer brushes onto solid surfaces are a powerful means of controlling the chemical and physical properties of solid interfaces and an important branch of surface and interface engineering research. By grafting polymers with different properties onto solid surfaces, surface modification can be achieved, allowing for precise control of solid surface properties and endowing materials with various functions: wettability, biocompatibility, corrosion resistance, stain resistance, smoothness, antibacterial properties, adsorption of specific substances, responsiveness to different stimuli, and recognition of biomolecules, etc., with wide applications in catalysis, electronics, nanomaterial synthesis, and biosensors.

[0003] Photo-induced atom transfer radical polymerization (Photo-ATRP) is a controlled radical polymerization technique that provides an efficient and simple method for grafting polymer brushes onto solid substrates. It utilizes light as an energy source to initiate polymerization, exhibiting significant green chemical properties. Compared to thermally initiated, enzyme-catalyzed, electrochemically, or ultrasonically initiated polymerization processes, photo-induced polymerization offers a more versatile method for preparing polymer brushes. This technology boasts advantages such as simple reaction apparatus, mild oxygen resistance, mild conditions, and environmental friendliness, and allows for time-controlled polymerization.

[0004] Catalysts / systems play a crucial role in photo-ATRP, serving as the core element for achieving controlled polymerization. Based on differences in catalytic mechanisms, currently reported catalysts / systems can be categorized into three types: photo-oxidative quenching, photo-reduction quenching, and transition metal complex-mediated. Studies have shown that these three types of catalysts / systems are applicable to the photo-controlled polymerization of almost all acrylate monomers, exhibiting excellent monomer versatility. Among them, copper bromide complexes with nitrogen-containing ligands are the most efficient transition metal complex catalytic systems, possessing a wider range of applicability and frequently reported in the literature.

[0005] In copper bromide complex catalytic systems, ligands play a crucial role in the catalysis of photo-ATRP, serving as a decisive factor in regulating polymerization performance. If the development of photo-ATRP catalytic systems is one main thread in the development of photo-ATRP, then the development of corresponding ligands is undoubtedly another. New catalysts / systems require ligands with higher activity, while simultaneously, more active ligands promote the further development of photo-ATRP catalysts / systems.

[0006] Over the past three decades, the discovery and development of highly active ligands have revealed that their influence on the equilibrium constant of controlled polymerization reactions can span orders of magnitude. Generally, the activity of copper-catalyzed systems containing different ligands decreases in the following order: alkylamines ≈ pyridine > alkylimines > arylimines > arylamines. Based on the number of nitrogen atoms, ligands can also be classified as tetradentate, tridentate, and bidentate ligands, with their catalytic strength decreasing sequentially. Among these, the tetradentate linear ligand tris(2-dimethylaminoethyl)amine (Me6-TREN) exhibits the best catalytic activity, offering good controllability and high catalytic efficiency in polymerization. It is considered the best-performing ligand, especially in the preparation of photo-ATRP surface-grafted polymer brushes. However, this ligand is expensive (2714 RMB / mL, Sigma-Aldrich brand), making it unsuitable for large-scale industrial applications. To reduce costs, Feng Xiaojing et al. blended Me6-TREN with its analogue tris(2-aminoethyl)amine (TREN) in a 1:1 molar ratio and found that it improved performance in conventional atom transfer radical polymerization catalyzed by zero-valent copper. Furthermore, the latter was only 80% the price of the former, and TREN is a commonly used tetradentate ligand in copper complexes. In addition, there are few reports on other mixed ligands.

[0007] Therefore, there is an urgent need in this field to develop a new catalytic system that can maintain or even surpass the excellent catalytic performance of Me6-TREN while significantly reducing costs, thereby enabling the industrial application of Photo-ATRP technology. Summary of the Invention

[0008] The purpose of this invention is to solve the problems existing in the above-mentioned background art and to provide a low-cost, high-activity catalyst system for photoinduced atom transfer radical polymerization.

[0009] The present invention also provides an application of the catalyst system in photoinduced atom transfer radical polymerization.

[0010] The technical solution adopted by this invention to solve its technical problem is:

[0011] A catalyst system for photoinduced atom transfer radical polymerization comprises: (a) copper bromide; and (b) a mixed ligand consisting of a first ligand and a second ligand; wherein the first ligand is tris(2-dimethylaminoethyl)amine (Me6-TREN); and the second ligand is one or more small molecule amines selected from ammonia, piperidine and its derivatives, piperazine and its derivatives, piperazineone and its derivatives, morpholine and its derivatives, and tetramethylethylenediamine.

[0012] The inventors have surprisingly discovered that combining a trace amount of the first ligand (Me6-TREN) with an excess of an inexpensive second ligand (a chain-like or cyclic small molecule amine) can produce a significant synergistic effect, exhibiting performance as excellent as when Me6-TREN is used alone. This significantly reduces the cost of using Me6-TREN.

[0013] Preferably, the second ligand is one or more cyclic amines selected from piperidine, piperazine, piperazineone, morpholine, and their derivatives. More preferably, the second ligand is piperidine.

[0014] Preferably, the total molar ratio of copper bromide to the mixed ligands is 1:20 to 1:100; and the molar ratio of the second ligand to the first ligand is 10:1 to 150:1. At these ratios, the catalytic system exhibits excellent activity.

[0015] Preferably, the catalytic system is added to the polymerization system to prepare the photo-ATRP reaction solution. Based on 100% of the total weight of the polymerization system, the catalyst system comprises: 0.015 wt% copper bromide; 0.014-0.083 wt% tris(2-dimethylaminoethyl)amine; and 0.281-2.212 wt% small molecule amine. The polymerization system consists of monomers and solvents used in the reaction. The choice of solvent is conventional for those skilled in the art and is not the focus of this invention, so it will not be elaborated here. This invention uses dimethyl sulfoxide as the solvent for experiments. Dimethyl sulfoxide is a commonly used solvent in photo-ATRP and has good solubility for most compounds.

[0016] A reaction solution for photo-induced atom transfer radical polymerization (Photo-ATRP) comprising the catalyst system described in this invention. It also comprises a polymerization system consisting of monomers and a solvent.

[0017] A method for grafting polymer brushes onto a solid surface, the method comprising the steps of: carrying out a polymerization reaction under light irradiation on a solid surface having an atom transfer radical polymerization initiator, using the catalyst system or reaction solution described in this invention. The photopolymerization monomer is a conventional free radical polymerization monomer.

[0018] Preferably, the illumination conditions are: 1.53 ± 0.2 mW / cm². 2 Irradiate at a 365 nm light source for 1-3 hours. This irradiation method can produce polymer brushes with a thickness >100 nm.

[0019] Preferably, the polymerization reaction can be carried out under non-oxygen-removing conditions. This is another unexpected technical effect of the present invention, namely, the mixed ligand system endows the polymerization process with excellent oxygen resistance, greatly simplifying experimental operations and industrial production processes.

[0020] Preferably, the polymerizing monomer is a conventional free radical polymerizing monomer containing unsaturated double bonds, selected from one or more of acrylate monomers, methacrylate monomers, and acrylamide monomers. More specifically, it may be hydroxyethyl acrylate, hydroxyethyl methacrylate, methyl acrylate, methyl methacrylate, etc.

[0021] Preferably, the monomer containing unsaturated double bonds is selected from one or more of the following: hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylamide, N-isopropylacrylamide, ethylene glycol methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, potassium propyl methacrylate 3-sulfonate, methacryloylethyl sulfobetaine, methacryloyloxyethyl trimethylammonium chloride, and N,N-dimethylacrylamide.

[0022] The application of the catalyst system described in this invention in photoinduced atom transfer radical polymerization, particularly in applications aimed at reducing the amount of tris(2-dimethylaminoethyl)amine and / or improving the oxygen resistance of the polymerization system.

[0023] Preferably, the application involves mixing the catalytic system, monomer, and solvent together in a bottle with a rubber stopper to obtain a photo-ATRP reaction solution, followed by nitrogen purging to remove oxygen. A silicon wafer with an ATRP initiator surface-modified is placed in a sealed glass chamber and purged with a nitrogen stream. A suitable amount of the prepared reaction solution is drawn from the sample bottle using a microsyringe and dropped onto the silicon wafer surface under nitrogen protection, followed by covering with a coverslip to form a thin sandwich structure. Before sealing, the chamber is purged with nitrogen again, and finally sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity is controlled by adjusting the distance between the light source and the chamber (monitored using a photometer). After the reaction is complete, the silicon wafer is removed, thoroughly rinsed with DMF, and dried under a nitrogen stream to obtain a silicon wafer with polymer grafted onto its surface. Alternatively, the entire process may not require deoxygenation.

[0024] In existing technologies, the commonly used catalysts / systems for photo-ATRP are complexes composed of copper bromide and nitrogen-containing ligands. Among these, the recognized high-strength nitrogen-containing ligands are typically the tetradentate ligand Me6-TREN, tris(2-pyridinemethyl)amine, and some modified compounds synthesized from their parent compounds, all of which are used alone. Me6-TREN exhibits the best performance and is a commonly used ligand in copper-catalyzed photo-ATRP; however, its high price limits its large-scale industrial application. Compared with existing technologies, the advantages of this invention are:

[0025] 1. This invention achieves catalytic effects comparable to or even better than using high-concentration Me6-TREN alone by combining a very small amount of expensive Me6-TREN with a large amount of inexpensive and readily available small-molecule amines. Experiments have shown that using only about 1 / 8 the amount of Me6-TREN can achieve the same polymer brush growth thickness, thereby reducing catalyst costs by an order of magnitude.

[0026] 2. The mixed ligand system of this invention exhibits excellent oxygen resistance, allowing the polymerization reaction to proceed efficiently without the need for a rigorous nitrogen purging and deoxygenation process. This not only simplifies laboratory operations but, more importantly, eliminates the stringent requirements for inert gas protection in industrial production, reducing equipment investment and production risks.

[0027] 3. This catalytic system exhibits high activity, enabling rapid polymerization under mild light irradiation to produce dense polymer brushes with thicknesses exceeding 100 nm, even reaching 180 nm. Furthermore, the system demonstrates excellent catalytic performance for various hydrophilic / hydrophobic monomers, including acrylates and methacrylates, showcasing broad monomer versatility.

[0028] 4. The small molecule amines used as the main ligands are all mature industrial products, widely available, and inexpensive. They can be used simply by mixing with Me6-TREN, making the operation extremely convenient. Attached Figure Description

[0029] Figure 1 It refers to the thickness of the photo-induced surface grafted polymer brush in a composite system of different small molecule amines, Me6-TREN mixed ligands, and copper bromide. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0031] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0032] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0033] All compounds mentioned in the examples were purchased from Aladdin Reagents (Shanghai) Co., Ltd.

[0034] The present invention provides a catalytic system composed of copper bromide and its ligands, wherein the ligands are a mixture of small molecule amines as the main component and a small amount of Me6-TREN. The performance of this catalytic system in the catalytic initiation of photo-ATRP surface initiation for the preparation of polymer brushes is comparable to that of Me6-TREN used alone as a ligand. These small molecule amine compounds are mature commercial products, widely available, and inexpensive; they also exhibit excellent water solubility and good miscibility with most organic solvents, thus demonstrating good compatibility with various polymerization systems. Using these small molecule amines as the main component mixed with a small amount of Me6-TREN as a ligand can significantly reduce the amount of expensive Me6-TREN used while maintaining the same catalytic performance, thereby greatly reducing application costs and promising industrial application.

[0035] The inventors discovered that a catalytic system composed of a mixture of small molecule amine compounds and Me6-TREN as mixed ligands and copper bromide can catalyze the preparation of polymer brushes or polymers with controllable molecular weight by photo-ATRP. This is a previously undiscovered photo-ATRP catalytic system with excellent performance.

[0036] The inventors have discovered for the first time that a mixed ligand consisting of these small-molecule amine compounds and Me6-TREN exhibits a synergistic effect in copper bromide-catalyzed photo-ATRP, a function not present when used alone. While increasing the amount of Me6-TREN used alone can significantly improve the catalytic effect of the copper bromide catalytic system, this comes at the cost of increased operating costs. By using the small-molecule amines of this invention as the main component, combined with a small amount of Me6-TREN, and further increasing the proportion of small-molecule amines, the catalytic effect of the copper bromide system can also be significantly improved, with very limited cost increase.

[0037] The aforementioned small-molecule amine compounds are all commercially available products, with a wide selection, easy purchase, and low price. Simply mixing them with Me6-TREN allows them to be directly combined with copper bromide to form a catalytic system. This system can then be added to the polymerization system to catalyze the preparation of polymer brushes or high molecular weight compounds with controllable molecular weight via photo-ATRP, making it very convenient to use.

[0038] Example 1

[0039] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0040] First component: Copper bromide, 0.015%,

[0041] Second component: Me6-TREN, 0.083%,

[0042] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0043] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0044] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0045] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 1 in Table 1.

[0046] Example 2

[0047] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0048] First component: Copper bromide, 0.015%,

[0049] Second component: Me6-TREN, 0.166%,

[0050] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0051] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0052] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0053] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 2 in Table 1.

[0054] Example 3

[0055] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0056] First component: Copper bromide, 0.015%,

[0057] Second component: Me6-TREN, 0.332%.

[0058] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0059] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0060] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0061] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 3 in Table 1.

[0062] Example 4

[0063] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0064] First component: Copper bromide, 0.015%,

[0065] Second component: Me6-TREN, 0.042%,

[0066] Third component: Tetramethylethylenediamine, 2.212%,

[0067] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0068] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0069] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0070] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 4 in Table 1.

[0071] Example 5

[0072] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0073] First component: Copper bromide, 0.015%,

[0074] Second component: Me6-TREN, 0.042%,

[0075] Third component: ammonia, 0.553%.

[0076] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0077] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0078] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0079] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 5 in Table 1.

[0080] Example 6

[0081] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0082] First component: Copper bromide, 0.015%,

[0083] Second component: Me6-TREN, 0.042%,

[0084] Third component: 2-piperazinone, 0.562%,

[0085] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0086] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0087] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0088] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 6 in Table 1.

[0089] Example 7

[0090] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0091] First component: Copper bromide, 0.015%,

[0092] Second component: Me6-TREN, 0.042%,

[0093] Third component: Piperidine, 0.281%,

[0094] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0095] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0096] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0097] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 7 in Table 1.

[0098] Example 8

[0099] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0100] First component: Copper bromide, 0.015%,

[0101] Second component: Me6-TREN, 0.042%,

[0102] Third component: Morpholine, 0.281%,

[0103] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0104] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0105] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0106] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample No. 8 in Table 1.

[0107] Example 9

[0108] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0109] First component: Copper bromide, 0.015%,

[0110] Second component: Me6-TREN, 0.014%,

[0111] Third component: Piperidine, 0.281%,

[0112] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl acrylate in the polymerization system being 100%.

[0113] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0114] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0115] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 9 in Table 1.

[0116] Example 10

[0117] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0118] First component: Copper bromide, 0.015%,

[0119] Second component: Me6-TREN, 0.014%,

[0120] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of methyl methacrylate in the polymerization system being 100%.

[0121] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0122] Preparation of photopolymerization reaction solution: The above catalytic system was mixed with 50% of the monomer and 50% of the solvent dimethyl sulfoxide in a vial to obtain the reaction solution for photo-ATRP reaction.

[0123] Photo-ATRP grafting of methyl methacrylate polymer onto silicon wafer surface: A silicon wafer with ATRP initiator grafted onto its surface is placed on a glass slide. 10 µL of the prepared solution is drawn from the sample vial using a microsyringe and added dropwise to the silicon wafer surface. A 1.5 × 1.5 cm coverslip is then placed over the wafer to form a thin sandwich structure, which is then irradiated under a light source. The light intensity is controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 1 hour, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 10 in Table 1.

[0124] Example 11

[0125] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0126] First component: Copper bromide, 0.015%,

[0127] Second component: Me6-TREN, 0.014%,

[0128] Third component: Piperidine, 1.105%,

[0129] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of methyl methacrylate in the polymerization system being 100%.

[0130] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0131] Preparation of photopolymerization reaction solution: The above catalytic system was mixed with 50% of the monomer and 50% of the solvent dimethyl sulfoxide in a vial to obtain the reaction solution for photo-ATRP reaction.

[0132] Photo-ATRP grafting of methyl methacrylate polymer onto silicon wafer surface: A silicon wafer with ATRP initiator grafted onto its surface is placed on a glass slide. 10 µL of the prepared solution is drawn from the sample vial using a microsyringe and added dropwise to the silicon wafer surface. A 1.5 × 1.5 cm coverslip is then placed over the wafer to form a thin sandwich structure, which is then irradiated under a light source. The light intensity is controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 1 hour, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 11 in Table 1.

[0133] Example 12

[0134] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0135] First component: Copper bromide, 0.015%,

[0136] Second component: Me6-TREN, 0.332%.

[0137] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of methyl acrylate in the polymerization system being 100%.

[0138] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0139] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0140] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 12 in Table 1.

[0141] Example 13

[0142] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0143] First component: Copper bromide, 0.015%,

[0144] Second component: Me6-TREN, 0.042%,

[0145] Third component: Piperidine, 0.562%.

[0146] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of methyl acrylate in the polymerization system being 100%.

[0147] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0148] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0149] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 13 in Table 1.

[0150] Example 14

[0151] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0152] First component: Copper bromide, 0.015%,

[0153] Second component: Me6-TREN, 0.332%.

[0154] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of hydroxyethyl methacrylate in the polymerization system being 100%.

[0155] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0156] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0157] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 14 in Table 1.

[0158] Example 15

[0159] A catalytic system consisting of copper bromide and a nitrogen-containing ligand, the components of which are as follows:

[0160] First component: Copper bromide, 0.015%,

[0161] Second component: Me6-TREN, 0.014%,

[0162] Third component: Piperidine, 0.562%,

[0163] The catalytic system was prepared according to the above proportions, with the weight of the dimethyl sulfoxide solution of methyl methacrylate in the polymerization system being 100%.

[0164] Preparation of ATRP initiator grafted onto silicon wafer surface: Silicon wafers measuring 0.8 × 1.0 cm were ultrasonically cleaned sequentially in ethanol, water, and acetone (5 minutes each). After drying with nitrogen, the cleaned silicon wafers were cleaned with a UV ozone cleaner for 25 minutes to generate hydroxyl groups on their surface. These hydroxyl-containing silicon wafers were then immediately transferred to a dried petri dish, and an anhydrous toluene solution containing 10 mM 3-(triethoxysilyl)propyl 2-bromo-2-methylpropionate (ATRP initiator) was added. The mixture was shaken at room temperature for 30 minutes. After the reaction was complete, the silicon wafers were removed and thoroughly cleaned sequentially with toluene, ethanol, and dichloromethane. After drying with nitrogen, the silicon substrate with ATRP initiator surface modification was obtained for subsequent use.

[0165] Preparation of photopolymerization reaction solution: The above catalytic system, together with 50% of the monomer and 50% of the solvent dimethyl sulfoxide, is added to a small bottle with a rubber stopper and mixed to obtain the reaction solution for photo-ATRP reaction, and then nitrogen is purged to remove oxygen.

[0166] Photo-ATRP grafting of hydroxyethyl acrylate polymer onto silicon wafers: A silicon wafer with ATRP initiator grafted onto its surface was placed in a sealed glass chamber and purged with nitrogen for 10 minutes. Using a microsyringe, 10 µL of the prepared solution was drawn from the sample vial and added dropwise to the silicon wafer surface under nitrogen protection. A 1.5 × 1.5 cm coverslip was then placed over the wafer to form a thin sandwich structure. Before sealing, the chamber was purged with nitrogen for another 10 minutes. Finally, the chamber was sealed with a rubber septum and immediately placed under a light source for irradiation. The light intensity was controlled by adjusting the distance between the light source and the chamber (monitored using a photometer) to achieve an intensity of 1.53 mW / cm². 2 After irradiation for 2 hours, the silicon wafer was removed, thoroughly rinsed with DMF, and dried under a nitrogen flow to obtain a silicon wafer with polymer brushes grafted onto its surface, as shown in sample 15 in Table 1.

[0167] The above embodiments describe a method and process for catalyzing the grafting and growth of polymer brushes onto the surface of a silicon wafer connected to a conventional ATRP initiator using different ligand-copper bromide complexes as catalytic systems. The thickness of the brush was used as an indicator to evaluate the catalytic activity of the system. Under the same test conditions, a thicker polymer brush resulted in better catalytic performance, as shown in Table 1. Figure 1 As shown.

[0168] Table 1

[0169] Example <![CDATA[CuBr2 (mass percentage)]]> <![CDATA[Me6-TREN (mass percentage)]]> Small molecule amines (percentage content) Dimethyl sulfoxide percentage monomer percentage Polymer brush thickness (nm) Remark 1 0.015% 0.083 % － 50% 50% (hydroxyethyl acrylate) 30 2-hour deoxygenation irradiation 2 0.015% 0.166 % － 50% 50% (hydroxyethyl acrylate) 40-50 2-hour deoxygenation irradiation 3 0.015% 0.332 % － 50% 50% (hydroxyethyl acrylate) 135 2-hour deoxygenation irradiation 4 0.015% 0.042 % Tetramethylethylenediamine (2.212%) 50% 50% (hydroxyethyl acrylate) 150 2-hour deoxygenation irradiation 5 0.015% 0.042 % Ammonia (0.553%) 50% 50% (hydroxyethyl acrylate) 135 2-hour deoxygenation irradiation 6 0.015% 0.042 % 2-Piperazinone (0.562%) 50% 50% (hydroxyethyl acrylate) 135 2-hour deoxygenation irradiation 7 0.015% 0.042 % Piperidine (0.281%) 50% 50% (hydroxyethyl acrylate) 135 2-hour deoxygenation irradiation 8 0.015% 0.042 % Morpholine (0.281%) 50% 50% (hydroxyethyl acrylate) 135 2-hour deoxygenation irradiation 9 0.015% 0.014 % Piperidine (0.281%) 50% 50% (hydroxyethyl acrylate) 110 2-hour deoxygenation irradiation 10 0.015% 0.014 % － 50% 50% (Methyl methacrylate) brushless Irradiation for 1 hour without deoxygenation 11 0.015% 0.014 % Piperidine 1.105% 50% 50% (Methyl methacrylate) 160 Irradiation for 1 hour without deoxygenation 12 0.015% 0.332 % － 50% 50% (methyl acrylate) 150 2-hour deoxygenation irradiation 13 0.015% 0.042 % Piperidine 0.562% 50% 50% (methyl acrylate) 155 2-hour deoxygenation irradiation 14 0.015% 0.332 % － 50% 50% (hydroxyethyl methacrylate) 180 2-hour deoxygenation irradiation 15 0.015% 0.014 % Piperidine 0.562% 50% 50% (hydroxyethyl methacrylate) 180 2-hour deoxygenation irradiation

[0170] Table 1 shows the effects of different concentrations of the monoligand Me6-TREN on the catalytic performance of copper bromide in Examples 1-3. It can be seen that as the Me6-TREN concentration gradually increases from 0.083% to 0.332%, the thickness of the poly(hydroxyethyl acrylate) brush gradually increases from 30 nm to 135 nm, indicating a clear concentration-dependent relationship between the brush growth thickness and the amount of Me6-TREN used. Examples 4-8 show the growth of polymer brushes after mixing Me6-TREN at a low concentration of 0.042% with different concentrations of small molecule amines: tetramethylethylenediamine (2.212%), ammonia (0.553%), piperazine (0.562%), piperidine (0.281%), and morpholine (0.281%). It can be seen that polymer brushes with a thickness of 150 or 135 nm were obtained in all cases, while no brush could grow on the silicon wafer surface at the low concentration of Me6-TREN (0.042%). These results indicate that mixing low concentrations of Me6-TREN with small molecule amines can achieve the same catalytic effect as increasing the amount of Me6-TREN used alone. Therefore, this invention can reduce the amount of Me6-TREN used through the synergistic effect of mixing with small molecule amines, thereby reducing the cost of catalyst use. Example 9 further reduces the concentration of Me6-TREN to 0.014%, and after mixing with 0.281% piperidine, the thickness of the polyhydroxyethyl acrylate brush can still reach 110 nm.

[0171] The results showed that using only 0.042% Me6-TREN (about 1 / 8 of the amount used in Example 3), combined with an inexpensive small-molecule amine, a polymer brush with a diameter of 135-150 nm could be obtained. This demonstrates a significant synergistic effect between the first and second ligands, which can maintain or even surpass the catalytic performance at high concentrations while significantly reducing the amount of the expensive first ligand.

[0172] Table 1 compares the growth of methyl methacrylate polymer brushes in Examples 10 and 11 of the present invention using the single ligand Me6-TREN at a low concentration of 0.014% and when mixed with piperidine (1.105%), under conditions of no deoxygenation and an irradiation time of only 1 hour. It can be seen that no brushes were generated in the former case, while the latter resulted in brushes up to 160 nm thick. This indicates that the mixed ligand effect involving small molecule amines can effectively catalyze the graft polymerization of hydrophobic monomers under conditions of no deoxygenation, making the polymerization process somewhat tolerant to oxygen and simplifying the polymerization process and apparatus. Me6-TREN alone does not possess this function. This strongly demonstrates that the mixed ligand system of the present invention imparts excellent oxygen resistance to the polymerization process.

[0173] Table 1 shows Examples 12 and 13, which catalyze the growth of methyl acrylate polymer brushes with a different hydrophobic monomer, using a single ligand Me6-TREN (0.332%) and a mixed ligand of low concentrations of Me6-TREN (0.042%) and piperidine (0.562%), respectively. It can be seen that polymer brushes with thicknesses of 150 nm and 155 nm were obtained under the two conditions, respectively. This indicates that mixed ligands involving small molecule amines can effectively catalyze the grafting growth of methyl acrylate polymer brushes with a hydrophobic monomer when the amount of Me6-TREN used is reduced.

[0174] Table 1 shows Examples 14 and 15, which respectively catalyze the growth of hydroxyethyl methacrylate polymer brushes using a single ligand Me6-TREN (0.332%) and a mixed ligand of low concentrations of Me6-TREN (0.042%) and piperidine (0.562%). It can be seen that polymer brushes with a thickness of 180 nm were obtained under both conditions. This indicates that mixed ligands involving small molecule amines can effectively catalyze the grafting growth of hydrophilic hydroxyethyl methacrylate polymer brushes with reduced Me6-TREN usage.

[0175] Examples 10, 11, 12, 13, 14, and 15 demonstrate the broad monomer adaptability of the synergistic effect of the mixed ligands involving small molecule amines in the present invention in catalytic photo-ATRP. The results show that, regardless of the monomer, such as methyl acrylate or hydroxyethyl methacrylate, the mixed ligand system of the present invention can achieve catalytic effects comparable to high-concentration single-ligand systems with extremely low Me6-TREN dosage. This confirms the broad monomer adaptability of the catalytic system of the present invention.

[0176] In summary, the embodiments of the present invention fully demonstrate that the proposed mixed ligand catalyst system can achieve catalytic performance comparable to or even better than the best existing technologies at a significantly reduced cost, and brings additional advantages in oxygen resistance.

Claims

1. A catalyst system for photoinduced atom transfer radical polymerization, characterized in that, It comprises: (a) copper bromide; and (b) a mixed ligand consisting of a first ligand and a second ligand; wherein the first ligand is tris(2-dimethylaminoethyl)amine (Me6-TREN); and the second ligand is one or more small molecule amines selected from ammonia, piperidine and its derivatives, piperazine and its derivatives, piperazine ketone and its derivatives, morpholine and its derivatives, and tetramethylethylenediamine.

2. The catalyst system according to claim 1, characterized in that: The total molar ratio of copper bromide to the mixed ligand is 1:20 to 1:100; the molar ratio of the second ligand to the first ligand is 10:1 to 150:

1.

3. The catalyst system according to claim 1, characterized in that: The catalyst system is added to the polymerization system to prepare photo-ATRP reaction solution. Based on the total weight of the polymerization system (100%), the catalyst system contains: 0.015 wt% copper bromide; 0.014-0.083 wt% tris(2-dimethylaminoethyl)amine; and 0.281-2.212 wt% small molecule amine.

4. A reaction solution for photo-induced atom transfer radical polymerization (Photo-ATRP), characterized in that, It comprises the catalyst system as described in claim 1.

5. A method for grafting polymer brushes onto a solid surface, characterized in that... The method includes the following steps: Polymerization reaction is carried out on a solid surface with an atom transfer radical polymerization initiator under light irradiation using the catalyst system of claim 1 or the reaction solution of claim 4.

6. The method according to claim 5, characterized in that: The illumination conditions are: 1.53 ± 0.2 mW / cm². 2 Irradiate for 1-3 hours under a 365 nm light source.

7. The method according to claim 5, characterized in that: The polymerization reaction is carried out under non-oxygen-removing conditions.

8. The method according to claim 5, characterized in that: The polymerizable monomer is a monomer containing unsaturated double bonds, selected from one or more of acrylate monomers, methacrylate monomers, and acrylamide monomers.

9. The method according to claim 5, characterized in that: The monomer containing unsaturated double bonds is selected from one or more of the following: hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylamide, N-isopropylacrylamide, ethylene glycol methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, potassium propyl 3-sulfonate methacrylate, methacryloylethyl sulfobetaine, methacryloyloxyethyl trimethylammonium chloride, and N,N-dimethylacrylamide.

10. The application of the catalyst system according to claim 1 in photoinduced atom transfer radical polymerization.

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