A perfluoroalkylsilane coupling agent for surface modification of a material and a method for preparing the same

Abstract

The present application relates to the technical field of surface modification materials, and particularly relates to a perfluoroalkyl silane coupling agent for material surface modification and a preparation method thereof. The coupling agent comprises synergistically modified perfluoroalkyl triethoxysilane, an organic small-molecule functional regulator, an acid catalyst, a surfactant, a stabilizer, ethanol and deionized water. The synergistically modified perfluoroalkyl triethoxysilane is prepared by synergistic modification of perfluoroalkyl triethoxysilane, monohydroxyl column [5] arene, octakis(glycidyl ether propyl) silsesquioxane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane and 2,6-pyridine dimethyl formaldehyde through host-guest inclusion, epoxy-amine ring-opening reaction and Schiff base condensation reaction, and the organic small-molecule functional regulator is 9,10-dihydroxyanthracene. The preparation method is simple and suitable for surface modification of various substrates such as glass, metal, ceramic and polymer materials.

Description

Technical Field

[0001] This invention relates to the field of surface functionalized materials technology, specifically to a perfluoroalkylsilane coupling agent for material surface modification and its preparation method. Background Technology

[0002] Perfluoroalkylsilane coupling agents are widely used in the surface modification of substrates such as glass, metals, ceramics, and polymers due to their extremely low surface energy, excellent hydrophobic and oleophobic properties, and good chemical stability. Through hydrolysis and condensation reactions on the material surface, perfluoroalkylsilanes can form a fluorinated silicon-oxygen network structure, thereby endowing the material with excellent waterproof, oil-proof, stain-resistant, and corrosion-resistant properties. Therefore, they have significant application value in antifouling coatings, self-cleaning materials, electronic device surface treatment, and functional coatings.

[0003] However, existing perfluoroalkylsilane coupling agents still have certain limitations in practical applications. For example, the molecular structure of traditional perfluoroalkylsilanes is relatively simple, and the stability of the silicon-oxygen network structure formed on the material surface is limited. This network is easily damaged under conditions of friction, ultraviolet irradiation, or chemical corrosion, leading to a gradual decline in hydrophobic and oleophobic properties. Furthermore, due to the lack of effective control over the arrangement of fluorine chains in the interfacial layer, their orientation stability on the substrate surface is poor, thus affecting the durability of the surface modification effect.

[0004] To address these issues, existing technologies typically improve surface properties by introducing functional additives or increasing the amount of fluorosilanes. However, these methods often fail to improve the stability of the silane coupling layer at the molecular structure level, and excessively high fluorosilane content can even lead to decreased system stability. Therefore, developing a perfluoroalkyl silane coupling agent system capable of constructing a stable structure at the molecular level, improving the ordered arrangement of fluorine chains, and enhancing the stability of the silicon-oxygen network is of great significance for improving the durability and functionality of material surface modification. Summary of the Invention

[0005] In order to overcome the problems of insufficient stability of the silicon-oxygen network structure formed by perfluoroalkylsilane coupling agents on the material surface, unstable fluorine chain orientation, and poor surface modification durability in the above-mentioned background technology, the purpose of this invention is to provide a perfluoroalkylsilane coupling agent for material surface modification and its preparation method. This invention introduces monohydroxy columnar aromatic hydrocarbons [5], octa(glycidyl ether propyl) silsesquioxane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 2,6-pyridinedicarboxaldehyde through synergistic modification of perfluoroalkyltriethoxysilane, and constructs multiple synergistic structures through host-guest inclusion, epoxy-amine ring-opening reaction and Schiff base condensation reaction. At the same time, 9,10-dihydroxyanthracene is used as an organic small molecule functional regulator to form a stable synergistic modified perfluoroalkylsilane coupling agent system. This invention, by constructing a synergistic modification system of host-guest structure, cage-type organosilicon structure and Schiff base dynamic structure, can significantly improve the structural stability and fluorine chain orientation stability of perfluoroalkylsilanes on the material surface, thereby enhancing the hydrophobic and oleophobic properties and durability of the material surface.

[0006] The objective of this invention can be achieved through the following technical solutions: A perfluoroalkylsilane coupling agent for surface modification of materials, the coupling agent comprising the following raw materials in parts by weight: 35-75 parts of synergistically modified perfluoroalkyltriethoxysilane, 0.5-8 parts of organic small molecule functional regulator, 0.1-2 parts of acid catalyst, 0.1-2 parts of surfactant, 0.2-3 parts of stabilizer, 40-120 parts of ethanol, and 5-30 parts of deionized water; the synergistically modified perfluoroalkyltriethoxysilane is prepared by synergistic modification of perfluoroalkyltriethoxysilane, monohydroxy columnar aromatic [5], octa(glycidyl ether propyl) silsesquioxane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 2,6-pyridinedicarboxaldehyde through host-guest inclusion, epoxy-amine ring-opening reaction and Schiff base condensation reaction; the organic small molecule functional regulator is 9,10-dihydroxyanthracene.

[0007] Optionally, the synergistically modified perfluoroalkyltriethoxysilane comprises the following raw materials in parts by weight: 60-90 parts of perfluoroalkyltriethoxysilane, 1-10 parts of monohydroxy columnar[5] aromatic hydrocarbon, 2-12 parts of octa(glycidyl ether propyl) sesquioxane, 1-8 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 0.5-6 parts of 2,6-pyridinedicarboxaldehyde.

[0008] Optionally, the preparation method of synergistically modified perfluoroalkyltriethoxysilane includes the following steps: (1) The monohydroxy column[5] aromatic hydrocarbon was dispersed in an organic solvent, and then perfluoroalkyl triethoxysilane was added. The reaction was carried out under heating and stirring conditions to form a host-guest inclusion effect between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl chain segment, and a pre-assembled reaction solution was obtained. (2) Add octa(glycidyl ether propyl) sesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to the pre-assembled reaction solution and react under heating conditions to allow the epoxy group and amino group to undergo a ring-opening grafting reaction to obtain the intermediate product of cage-type organosilicon synergistic reconstruction. (3) Add 2,6-pyridinedicarboxaldehyde to the intermediate product and carry out a condensation reaction under stirring conditions, so that 2,6-pyridinedicarboxaldehyde and the residual amino group undergo Schiff base condensation reaction. After the reaction is completed, the product is aged to obtain the synergistically modified perfluoroalkyltriethoxysilane.

[0009] Optionally, the reaction conditions for step (1) are as follows: the monohydroxy column[5] aromatic hydrocarbon is added to ethanol or tetrahydrofuran solvent for dispersion, stirred at 300-600 rpm for 20-40 min at 40-70°C to fully dissolve it, and then perfluoroalkyl triethoxysilane is added. The reaction is continued to be stirred at 400-600 rpm for 1-3 h under nitrogen protection to form a stable host-guest inclusion structure between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl segment.

[0010] Optionally, the reaction conditions in step (2) are as follows: add octa(glycidyl ether propyl) silsesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to the pre-assembled reaction solution, and stir the reaction at 400-700 rpm for 2-5 h at 50-80 °C, so that the epoxy group in octa(glycidyl ether propyl) silsesquioxane undergoes a ring-opening grafting reaction with the amino group, thereby constructing a cage-type organosilicon crosslinked structure.

[0011] Optionally, the reaction conditions in step (3) are as follows: 2,6-pyridinedicarboxaldehyde is added to the intermediate product, and the mixture is stirred at 300-500 rpm for 1-4 h at 25-60 °C to allow 2,6-pyridinedicarboxaldehyde to undergo Schiff base condensation with the amino group in the system. Then, the mixture is aged at room temperature for 6-24 h to obtain synergistically modified perfluoroalkyltriethoxysilane.

[0012] Optionally, the acid catalyst is a mixture of glacial acetic acid and formic acid in a mass ratio of (2-6):(1-3); the surfactant is a mixture of polyoxyethylene octylphenyl ether and polyoxyethylene sorbitan monooleate in a mass ratio of (1-4):(1-3); and the stabilizer is a mixture of acetylacetone and p-methoxyphenol in a mass ratio of (2-5):(1-2).

[0013] Optionally, a method for preparing a perfluoroalkylsilane coupling agent for material surface modification includes the following steps: S1, Ethanol is added to the reaction vessel, and synergistically modified perfluoroalkyltriethoxysilane is added under stirring to fully disperse it. Then deionized water is added for mixing to obtain the silane hydrolysis reaction system. S2, add acid catalyst and surfactant to silane hydrolysis reaction system to carry out reaction, so that the synergistically modified perfluoroalkyltriethoxysilane undergoes hydrolysis and condensation reaction to obtain a uniformly dispersed silane solution. S3, add organic small molecule functional regulators and stabilizers to a uniformly dispersed silane solution to carry out the reaction. After the reaction is completed, the solution is cured to obtain a perfluoroalkyl silane coupling agent for material surface modification.

[0014] Optionally, the reaction conditions for step S1 are stirring at 300-500 rpm for 20-40 min at 20-40°C; and the reaction conditions for step S2 are stirring at 300-600 rpm for 30-90 min at 25-50°C.

[0015] Optionally, the reaction conditions for step S3 are: stirring at 300-600 rpm for 1-3 hours at 30-60°C, and aging at room temperature for 12-24 hours.

[0016] The beneficial effects of this invention are: This invention modifies the structure of perfluoroalkyltriethoxysilane by introducing a monohydroxy columnar aromatic hydrocarbon[5] to construct a host-guest inclusion structure. The rigid cavity is used to confine and regulate the perfluoroalkyl chain segments, so that the fluorine chain can form a more stable and orderly orientation arrangement on the material surface, thereby effectively reducing the surface energy of the material surface and improving the hydrophobic and oleophobic properties. Simultaneously, through the epoxy-amine ring-opening reaction between octa(glycidyl ether propyl)silsesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, a cage-like silsesquioxane rigid structure is introduced into the system, improving the spatial stability and cross-linking degree of the silane network structure, resulting in a surface-modified layer with better wear resistance and structural stability. Furthermore, a dynamic covalent structure is constructed by the Schiff base condensation reaction between 2,6-pyridinedicarboxaldehyde and amino groups, which can enhance the intermolecular forces and improve the interfacial structural stability. At the same time, 9,10-dihydroxyanthracene is introduced as an organic small molecule functional regulator. Its polycyclic aromatic rigid structure can form π-π stacking at the interface and form hydrogen bonds through hydroxyl groups, thereby further stabilizing the fluorine chain arrangement structure and enhancing the durability of the modified layer. This allows the obtained perfluoroalkyl silane coupling agent to form a structurally stable, oriented, low surface energy modified layer on the material surface, significantly improving the hydrophobic and oleophobic properties, as well as the wear resistance and weather resistance of the material surface. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 A comparison of the infrared spectra of perfluoroalkyltriethoxysilane and synergistically modified perfluoroalkyltriethoxysilane; Figure 2 This is a comparison chart of contact angle test results for samples with different ratios. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.

[0020] Example 1: The purpose of this example is to verify that when the amount of each raw material and the reaction conditions are in a low range, the synergistic modified structure constructed by the present invention can still form a stable synergistic modified perfluoroalkyltriethoxysilane and obtain a stable surface-modified perfluoroalkylsilane coupling agent.

[0021] S1, Preparation of synergistically modified perfluoroalkyltriethoxysilanes One part of monohydroxy column[5] aromatic hydrocarbon was added to ethanol for dispersion and stirred at 300 rpm for 20 min at 40 °C to dissolve it completely. Then, 60 parts of perfluoroalkyl triethoxysilane were added and stirred at 400 rpm for 1 h under nitrogen protection to form a host-guest inclusion structure between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl segment, thus obtaining a pre-assembled reaction solution. Two parts of octa(glycidyl ether propyl) sesquioxane and one part of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were added to the pre-assembled reaction solution and stirred at 400 rpm for 2 h at 50 °C to allow the epoxy group and amino group to undergo a ring-opening reaction, thus obtaining an intermediate product. Then, 0.5 parts of 2,6-pyridinedicarboxaldehyde were added to the intermediate product and stirred at 300 rpm for 1 h at 25 °C to allow the 2,6-pyridinedicarboxaldehyde and amino group to undergo a Schiff base condensation reaction, and aged at room temperature for 6 h to obtain a synergistically modified perfluoroalkyl triethoxysilane.

[0022] S2, Construction of Coupling Agent System Add 40 parts of ethanol to a reaction vessel, and add 35 parts of synergistically modified perfluoroalkyltriethoxysilane under stirring to disperse it fully. Then add 5 parts of deionized water and stir at 300 rpm for 20 min at 20 °C to allow partial hydrolysis of the silane. Then add 0.1 parts of acid catalyst and 0.1 parts of surfactant to the system and stir at 300 rpm for 30 min at 25 °C.

[0023] S3, Coupling agent preparation Add 0.5 parts of 9,10-dihydroxyanthracene and 0.2 parts of stabilizer to the above system, stir at 300 rpm for 1 h at 30 °C, and then mature at room temperature for 12 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0024] Example 2: The purpose of this example is to verify that when the content of each component and the reaction conditions are in a moderate range, the synergistic modified structure constructed in this invention can obtain a stable synergistic modified perfluoroalkyltriethoxysilane and form a structurally uniform and stable perfluoroalkylsilane coupling agent system.

[0025] S1, Preparation of synergistically modified perfluoroalkyltriethoxysilanes Five parts of monohydroxy columnar aromatic hydrocarbon[5] were dispersed in ethanol and stirred at 450 rpm for 30 min at 55 °C to dissolve it. Then, 75 parts of perfluoroalkyltriethoxysilane were added and stirred at 500 rpm for 2 h under nitrogen protection to form a host-guest inclusion structure. Then, 7 parts of octa(glycidyl ether propyl) sesquioxane and 4 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were added to the system and stirred at 550 rpm for 3 h at 65 °C to allow the epoxy group to undergo a ring-opening grafting reaction with the amino group. Then, 3 parts of 2,6-pyridinedicarboxaldehyde were added and stirred at 400 rpm for 2 h at 45 °C to allow the system to undergo a Schiff base condensation reaction with the amino group. The system was then aged at room temperature for 12 h to obtain a synergistically modified perfluoroalkyltriethoxysilane. Figure 1 As shown, the unmodified perfluoroalkyltriethoxysilane at 2940 cm⁻¹ -1 and 2870 cm -1 Absorption peaks for the –CH2– and –CH3 stretching vibrations appear nearby, at 1285 cm⁻¹. -1 1210 cm -1 A distinct absorption peak for C–F and CF2 stretching vibrations appears at 1135 cm⁻¹. -1 and 1070 cm -1 The presence of characteristic absorption peaks for Si–O–Si and Si–O–C at 3425 cm⁻¹ indicates that the original perfluoroalkylsilane structure is intact and possesses a typical silicon-oxygen bond structure. The modified silane exhibits characteristic absorption peaks at 3425 cm⁻¹ in its infrared spectrum. -1 and 3320 cm -1 New absorption peaks for O–H and N–H stretching vibrations appear at 1692 cm⁻¹. -1 A distinct C=N characteristic absorption peak appears at 1608 cm⁻¹. -1 and 1490 cm -1 The presence of an aromatic ring skeletal vibration peak at 1132 cm⁻¹ indicates that the monohydroxy column[5] aromatic hydrocarbon reacts with 2,6-pyridinedicarboxaldehyde to form a Schiff base structure; -1The significantly enhanced intensity of the Si–O–Si absorption peak indicates the formation of a more stable silicon-oxygen network structure in the system. Multiple structural units have been successfully introduced into the perfluoroalkylsilane system, proving that the synergistic modification of perfluoroalkyltriethoxysilane has been successfully constructed.

[0026] S2, Construction of Coupling Agent System Add 80 parts of ethanol to a reaction vessel, add 55 parts of synergistically modified perfluoroalkyltriethoxysilane under stirring, then add 18 parts of deionized water, stir at 400 rpm for 30 min at 30 °C to allow the silane to hydrolyze; then add 0.8 parts of acid catalyst and 0.8 parts of surfactant, stir at 450 rpm for 60 min at 40 °C. S3, Coupling agent preparation Four parts of 9,10-dihydroxyanthracene and 1.5 parts of stabilizer were added to the system, and the mixture was stirred at 450 rpm for 2 h at 45 °C. Then it was aged at room temperature for 18 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0027] Example 3: The purpose of this example is to verify that when the content of each component and the reaction conditions are in a high range, the synergistic modified structure constructed by the present invention can still be stably formed, and a high concentration of perfluoroalkylsilane coupling agent system can be prepared.

[0028] S1, Preparation of synergistically modified perfluoroalkyltriethoxysilanes Ten parts of monohydroxy columnar aromatic hydrocarbon[5] were dispersed in tetrahydrofuran solvent and stirred at 600 rpm for 40 min at 70 °C to dissolve it completely. Then, 90 parts of perfluoroalkyltriethoxysilane were added and stirred at 600 rpm for 3 h under nitrogen protection to form a stable host-guest inclusion structure. Then, 12 parts of octa(glycidyl ether propyl) sesquioxane and 8 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were added to the system and stirred at 700 rpm for 5 h at 80 °C to allow the epoxy group and amino group to undergo a ring-opening reaction to form a cage-like organosilicon structure. Then, 6 parts of 2,6-pyridinedicarboxaldehyde were added and stirred at 500 rpm for 4 h at 60 °C to allow the Schiff base condensation reaction to occur. The mixture was then aged at room temperature for 24 h to obtain synergistically modified perfluoroalkyltriethoxysilane. S2, Construction of Coupling Agent System 120 parts of ethanol were added to the reaction vessel, and 75 parts of synergistically modified perfluoroalkyltriethoxysilane were added under stirring. Then 30 parts of deionized water were added, and the mixture was stirred at 500 rpm for 40 min at 40 °C to allow the silane to hydrolyze. Then 2 parts of acid catalyst and 2 parts of surfactant were added, and the mixture was stirred at 600 rpm for 90 min at 50 °C. S3, Coupling agent preparation Eight parts of 9,10-dihydroxyanthracene and three parts of stabilizer were added to the system, and the mixture was stirred at 600 rpm for 3 h at 60 °C. Then it was aged at room temperature for 24 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0029] Comparative Example 1: The purpose of this comparative example is to verify the effect of the stability and surface modification effect of the obtained perfluoroalkyl silane coupling agent system when the synergistic modification of perfluoroalkyl triethoxysilane retains only the monohydroxy columnar [5] aromatic hydrocarbons to modify the host-guest binding of perfluoroalkyl triethoxysilane without introducing cage-type organosilicon ring-opening grafting structure and Schiff base condensation structure.

[0030] S1, Preparation of single host-guest modified perfluoroalkyltriethoxysilanes Five parts of monohydroxy column[5] aromatic hydrocarbon were dispersed in ethanol and stirred at 450 rpm for 30 min at 55 °C to dissolve it. Then, 75 parts of perfluoroalkyl triethoxysilane were added and stirred at 500 rpm for 2 h under nitrogen protection to form a host-guest inclusion structure between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl segment. After the reaction was completed, the mixture was aged at room temperature for 12 h to obtain a single host-guest modified perfluoroalkyl triethoxysilane. S2, Construction of Coupling Agent System 80 parts of ethanol were added to a reaction vessel, and 55 parts of single host-guest modified perfluoroalkyltriethoxysilane were added under stirring. Then 18 parts of deionized water were added, and the mixture was stirred at 400 rpm for 30 min at 30 °C to allow the silane to hydrolyze. Then 0.8 parts of acid catalyst and 0.8 parts of surfactant were added, and the mixture was stirred at 450 rpm for 60 min at 40 °C. S3, Coupling agent preparation Four parts of 9,10-dihydroxyanthracene and 1.5 parts of stabilizer were added to the system, and the mixture was stirred at 450 rpm for 2 h at 45 °C. Then it was aged at room temperature for 18 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0031] Comparative Example 2: The purpose of this comparative example is to verify the effect of retaining only octa(glycidyl ether propyl) silsesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane on the cage-like organosilicon ring-opening graft modification of perfluoroalkyltriethoxysilane, without introducing host-guest inclusion structures and Schiff base condensation structures, on the stability and surface modification effect of the resulting perfluoroalkylsilane coupling agent system.

[0032] S1, Preparation of single cage-type organosilicon-modified perfluoroalkyltriethoxysilane 75 parts of perfluoroalkyltriethoxysilane were dispersed in ethanol and stirred at 450 rpm for 30 min at 55 °C. Then, 7 parts of octa(glycidyl ether propyl) sesquioxane and 4 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were added to the system and stirred at 550 rpm for 3 h at 65 °C to allow the epoxy group and amino group to undergo a ring-opening grafting reaction to form a cage-like organosilicon modified structure. After the reaction was completed, the mixture was aged at room temperature for 12 h to obtain a single cage-like organosilicon modified perfluoroalkyltriethoxysilane. S2, Construction of Coupling Agent System Add 80 parts of ethanol to a reaction vessel, add 55 parts of single cage-type organosilicon modified perfluoroalkyltriethoxysilane under stirring, then add 18 parts of deionized water, stir at 400 rpm for 30 min at 30 °C to allow the silane to hydrolyze; then add 0.8 parts of acid catalyst and 0.8 parts of surfactant, stir at 450 rpm for 60 min at 40 °C. S3, Coupling agent preparation Four parts of 9,10-dihydroxyanthracene and 1.5 parts of stabilizer were added to the system, and the mixture was stirred at 450 rpm for 2 h at 45 °C. Then it was aged at room temperature for 18 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0033] Comparative Example 3: The purpose of this comparative example is to verify the effect on the stability and surface modification effect of the obtained perfluoroalkyl silane coupling agent system when the preparation method and construction conditions of the synergistically modified perfluoroalkyl triethoxysilane in Example 2 are kept unchanged, but the organic small molecule functional regulator 9,10-dihydroxyanthracene is not added.

[0034] S1, Preparation of synergistically modified perfluoroalkyltriethoxysilanes Five parts of monohydroxy columnar aromatic hydrocarbon[5] were dispersed in ethanol and stirred at 450 rpm for 30 min at 55 °C to dissolve it. Then, 75 parts of perfluoroalkyl triethoxysilane were added and stirred at 500 rpm for 2 h under nitrogen protection to form a host-guest inclusion structure. Then, 7 parts of octa(glycidyl ether propyl) sesquioxane and 4 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane were added to the system and stirred at 550 rpm for 3 h at 65 °C to allow the epoxy group to undergo a ring-opening grafting reaction with the amino group. Then, 3 parts of 2,6-pyridinedicarboxaldehyde were added and stirred at 400 rpm for 2 h at 45 °C to allow the system to undergo a Schiff base condensation reaction with the amino group. The system was then aged at room temperature for 12 h to obtain synergistically modified perfluoroalkyl triethoxysilane. S2, Construction of Coupling Agent System Add 80 parts of ethanol to a reaction vessel, add 55 parts of synergistically modified perfluoroalkyltriethoxysilane under stirring, then add 18 parts of deionized water, stir at 400 rpm for 30 min at 30 °C to allow the silane to hydrolyze; then add 0.8 parts of acid catalyst and 0.8 parts of surfactant, stir at 450 rpm for 60 min at 40 °C. S3, Coupling agent preparation Add 1.5 parts of stabilizer to the system, stir at 450 rpm for 2 h at 45 °C, and then mature at room temperature for 18 h to obtain a perfluoroalkylsilane coupling agent for material surface modification.

[0035] Performance testing: 1. Contact Angle Test Method Glass slides were used as test substrates. First, the surface of the glass slides was ultrasonically cleaned with ethanol and deionized water, and then dried at 60°C for later use. The perfluoroalkylsilane coupling agents prepared in the examples and comparative examples were uniformly coated onto the glass slide surface and cured at 100°C for 30 minutes to form a stable surface-modified layer on the substrate surface. The static contact angle of water droplets on the material surface was measured using a contact angle meter. Five different locations were selected for testing for each sample, and the average value was taken as the final result to evaluate the hydrophobic properties of the material surface.

[0036] 2. Test method for wear resistance The coupling agents obtained in the examples and comparative examples were coated onto clean glass substrate surfaces and cured at 100°C for 30 minutes to form surface-modified layers. Abrasion resistance was tested using a tribological testing machine. Under a certain load, a standard rubber friction head was used to reciprocate the sample surface for 500 cycles. After the friction was completed, the water contact angle of the sample surface was measured again, and the change in contact angle before and after friction was calculated to evaluate the abrasion resistance stability of the surface-modified layer.

[0037] 3. Test methods for chemical corrosion resistance The coupling agents obtained in the examples and comparative examples were coated onto the surface of a glass substrate and cured at 100°C for 30 min to form a modified layer. Subsequently, the samples were immersed in 5% hydrochloric acid solution, 5% sodium hydroxide solution, and ethanol solution, respectively, at room temperature for 24 h. After removal, the samples were rinsed with deionized water and dried at 60°C. The change in water contact angle on the sample surface was then measured to evaluate the chemical stability of the modified layer on the material surface.

[0038] 4. Adhesion Test Method The coupling agents obtained in the examples and comparative examples were coated onto the surface of a glass substrate and cured at 100°C for 30 minutes to form a modified layer. The coating adhesion was tested using the cross-cut test. A grid structure of specified dimensions was formed on the sample surface using a standard cross-cut knife. Standard adhesive tape was then applied to the grid area and quickly peeled off, and the coating peeling was observed. The adhesion level was evaluated based on the degree of coating peeling in the grid area, thereby determining the bonding stability of the coupling agent on the material surface.

[0039] Table 1 Performance test results of the examples and comparative samples As shown in Table 1, there are significant differences in the performance of the materials after surface modification among the different embodiments and comparative samples. The perfluoroalkylsilane coupling agents prepared in Examples 1-3 of this invention all exhibit high water contact angles, among which... Figure 2 The water contact angle of Example 1 was 150.3°, that of Example 3 was 153.9°, and that of Example 2 reached 158.7°, significantly higher than the comparative samples. The comparative samples had water contact angles of 139.4°, 143.2°, and 146.8° for Comparative Example 1 and 3, respectively. These results demonstrate that synergistic modification of perfluoroalkyltriethoxysilane and the introduction of small organic molecule functional modifiers can effectively reduce the surface energy of the material, allowing the fluorine chains to form a more stable and ordered arrangement on the material surface, thereby significantly improving the hydrophobic properties of the material.

[0040] The wear resistance test results show that after 500 friction cycles, the contact angle of Example 1 was 142.6°, Example 3 was 147.1°, while Example 2 maintained a relatively high level of 153.4°, with contact angle retention rates of 94.9%, 95.6%, and 96.7%, respectively. In contrast, the contact angle of Comparative Example 1 after friction was 120.7°, Comparative Example 2 was 125.6°, and Comparative Example 3 was 132.4°, with contact angle retention rates of 86.6%, 87.7%, and 90.2%, respectively. These results indicate that the present invention can significantly improve the structural stability of the surface modified layer through the synergistic effect of the monohydroxy columnar [5] aromatic host-guest inclusion structure, silsesquioxane cage structure, and Schiff base dynamic structure, thereby enhancing the wear resistance of the material surface.

[0041] The chemical corrosion resistance test results show that the contact angles of Examples 1, 2, and 3 after treatment with acids, alkalis, and organic solvents were 146.8°, 155.6°, and 150.2°, respectively, maintaining a high level. In contrast, the contact angles of Comparative Examples 1, 2, and 3 after treatment were 128.3°, 132.7°, and 138.6°, respectively, significantly lower than the example samples. This indicates that the synergistic modification structure constructed in this invention can effectively improve the stability of the silane network structure, enabling the modified layer on the material surface to maintain good stability in complex chemical environments.

[0042] The adhesion test results show that Examples 1 and 3 both achieved an adhesion grade of 1, while Example 2 reached grade 0, exhibiting the best adhesion performance. In contrast, Comparative Examples 1 and 2 both achieved an adhesion grade of 2, and Comparative Example 3 achieved a grade of 1, indicating that the bonding stability between the coating and the substrate is significantly reduced when only a single modified structure is used or when organic small molecule regulation is lacking. This invention, through the construction of multiple synergistic modified structures, enables the silane coupling agent to form a more stable interfacial structure on the material surface, thereby effectively improving adhesion.

[0043] In summary, this invention constructs a synergistic modification system of host-guest inclusion structure, cage-like organosilicon structure, and Schiff base dynamic structure, and introduces 9,10-dihydroxyanthracene as an organic small molecule functional regulator, enabling the obtained perfluoroalkylsilane coupling agent to form a stable and ordered low surface energy structure on the material surface, thereby significantly improving the hydrophobicity, wear resistance, chemical stability, and adhesion of the material surface. Among these, Example 2 showed the best performance in all performance tests.

Claims

1. A perfluoroalkylsilane coupling agent for surface modification of materials, characterized in that, The coupling agent comprises the following raw materials in parts by weight: 35-75 parts of synergistically modified perfluoroalkyltriethoxysilane, 0.5-8 parts of organic small molecule functional regulator, 0.1-2 parts of acid catalyst, 0.1-2 parts of surfactant, 0.2-3 parts of stabilizer, 40-120 parts of ethanol, and 5-30 parts of deionized water; the synergistically modified perfluoroalkyltriethoxysilane is prepared by synergistic modification of perfluoroalkyltriethoxysilane, monohydroxy columnar aromatic hydrocarbon, octa(glycidyl ether propyl) silsesquioxane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 2,6-pyridinedicarboxaldehyde through host-guest inclusion, epoxy-amine ring-opening reaction and Schiff base condensation reaction; the organic small molecule functional regulator is 9,10-dihydroxyanthracene.

2. The perfluoroalkylsilane coupling agent for material surface modification according to claim 1, characterized in that, The synergistically modified perfluoroalkyltriethoxysilane comprises the following raw materials in parts by weight: 60-90 parts of perfluoroalkyltriethoxysilane, 1-10 parts of monohydroxy columnar[5] aromatic hydrocarbon, 2-12 parts of octa(glycidyl ether propyl) sesquioxane, 1-8 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 0.5-6 parts of 2,6-pyridinedicarboxaldehyde.

3. A perfluoroalkylsilane coupling agent for material surface modification according to claim 1 or 2, characterized in that, The preparation method of the synergistically modified perfluoroalkyltriethoxysilane includes the following steps: (1) The monohydroxy column[5] aromatic hydrocarbon was dispersed in an organic solvent, and then perfluoroalkyl triethoxysilane was added. The reaction was carried out under heating and stirring conditions to form a host-guest inclusion effect between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl chain segment, and a pre-assembled reaction solution was obtained. (2) Add octa(glycidyl ether propyl) sesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to the pre-assembled reaction solution and react under heating conditions to allow the epoxy group and amino group to undergo a ring-opening grafting reaction to obtain the intermediate product of cage-type organosilicon synergistic reconstruction. (3) Add 2,6-pyridinedicarboxaldehyde to the intermediate product and carry out a condensation reaction under stirring conditions, so that 2,6-pyridinedicarboxaldehyde and the residual amino group undergo Schiff base condensation reaction. After the reaction is completed, the product is aged to obtain the synergistically modified perfluoroalkyltriethoxysilane.

4. A perfluoroalkylsilane coupling agent for material surface modification according to claim 3, characterized in that, The reaction conditions for step (1) are as follows: the monohydroxy column[5] aromatic hydrocarbon is added to ethanol or tetrahydrofuran solvent for dispersion, stirred at 300-600 rpm for 20-40 min at 40-70°C to fully dissolve it, and then perfluoroalkyl triethoxysilane is added. Under nitrogen protection, the reaction is continued to be stirred at 400-600 rpm for 1-3 h to form a stable host-guest inclusion structure between the monohydroxy column[5] aromatic hydrocarbon and the perfluoroalkyl chain segment.

5. A perfluoroalkylsilane coupling agent for material surface modification according to claim 3, characterized in that, The reaction conditions for step (2) are as follows: add octa(glycidyl ether propyl) silsesquioxane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to the pre-assembled reaction solution, and stir at 400-700 rpm for 2-5 hours at 50-80°C to allow the epoxy groups in octa(glycidyl ether propyl) silsesquioxane to undergo a ring-opening grafting reaction with the amino groups, thereby constructing a cage-type organosilicon crosslinked structure.

6. A perfluoroalkylsilane coupling agent for material surface modification according to claim 3, characterized in that, The reaction conditions for step (3) are as follows: 2,6-pyridinedicarboxaldehyde is added to the intermediate product, and the mixture is stirred at 300-500 rpm for 1-4 h at 25-60 °C to allow 2,6-pyridinedicarboxaldehyde to undergo Schiff base condensation with the amino group in the system. Then, the mixture is aged at room temperature for 6-24 h to obtain synergistically modified perfluoroalkyltriethoxysilane.

7. A perfluoroalkylsilane coupling agent for material surface modification according to claim 1, characterized in that, The acid catalyst is a mixture of glacial acetic acid and formic acid in a mass ratio of (2-6):(1-3); the surfactant is a mixture of polyoxyethylene octylphenyl ether and polyoxyethylene sorbitan monooleate in a mass ratio of (1-4):(1-3); and the stabilizer is a mixture of acetylacetone and p-methoxyphenol in a mass ratio of (2-5):(1-2).

8. A method for preparing a perfluoroalkylsilane coupling agent for material surface modification, characterized in that, The preparation method includes the following steps: S1, Ethanol is added to the reaction vessel, and synergistically modified perfluoroalkyltriethoxysilane is added under stirring to fully disperse it. Then deionized water is added for mixing to obtain the silane hydrolysis reaction system. S2, add acid catalyst and surfactant to silane hydrolysis reaction system to carry out reaction, so that the synergistically modified perfluoroalkyltriethoxysilane undergoes hydrolysis and condensation reaction to obtain a uniformly dispersed silane solution. S3, add organic small molecule functional regulators and stabilizers to a uniformly dispersed silane solution to carry out the reaction. After the reaction is completed, the solution is cured to obtain a perfluoroalkyl silane coupling agent for material surface modification.

9. The method for preparing a perfluoroalkylsilane coupling agent for material surface modification according to claim 8, characterized in that, The reaction conditions for step S1 are stirring at 300-500 rpm for 20-40 min at 20-40℃; the reaction conditions for step S2 are stirring at 300-600 rpm for 30-90 min at 25-50℃.

10. The method for preparing a perfluoroalkylsilane coupling agent for material surface modification according to claim 8, characterized in that, The reaction conditions for step S3 are: stirring at 300-600 rpm for 1-3 hours at 30-60°C, and aging at room temperature for 12-24 hours.

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