Photoresponse type hydrogen-containing silicone oil intelligent coating and preparation method thereof

Abstract

The invention relates to the technical field of intelligent coating materials, in particular to a photoresponse type hydrogen-containing silicone oil intelligent coating and a preparation method thereof. Comprising a base material and a functional coating coated on the surface of the base material, the functional coating is formed by combining hydrogen-containing silicone oil, a photoresponsive monomer and surface modified nanoparticles through covalent bonds or hydrogen bonds, and the functional coating can generate reversible performance change under the irradiation of light with specific wavelength. The photoresponsive monomer, the surface-modified nanoparticles and the hydrogen-containing silicone oil are combined through covalent bonds or hydrogen bonds, so that reversible performance regulation and control of the coating under irradiation of light with specific wavelength are realized, meanwhile, the mechanical stability of the coating is improved, and the service life of the coating is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent coating materials, and particularly relates to a light-responsive hydrogen-containing silicone oil intelligent coating and a preparation method thereof. BACKGROUND

[0002] The hydrogen-containing silicone oil is widely used in the field of coating materials due to excellent high and low temperature resistance, weather resistance, hydrophobicity and chemical stability. However, the traditional hydrogen-containing silicone oil coating has single function and can only provide basic protection, and cannot realize dynamic regulation of performance according to changes in the external environment, thereby limiting its application in the field of intelligent materials.

[0003] Based on the above, the present inventors found that:

[0004] The light-responsive intelligent coating as a new type of functional material can change performance under the stimulation of specific wavelength light, and the change is usually reversible, which shows broad prospects in the fields of intelligent switches, biomedical devices and adaptive surfaces. The existing light-responsive coatings mostly use azobenzene, spiropyran and other light-responsive groups, but have the following problems: first, the light-responsive groups have weak bonding force with the coating matrix, are easy to fall off during use, and cause attenuation of the response performance; second, the mechanical performance and light-responsive performance of the coating are difficult to be considered, and after adding the light-responsive components, the hardness of the coating often decreases and the wear resistance becomes poor; third, some light-responsive coatings can only change performance under single wavelength light, have poor reversibility and slow response speed.

[0005] Therefore, in view of the above problems, the existing structure is improved, and a light-responsive hydrogen-containing silicone oil intelligent coating and a preparation method thereof are provided to solve the above problems. SUMMARY

[0006] In view of the problems of single function of the existing hydrogen-containing silicone oil coating, poor stability and insufficient performance reversibility of the light-responsive coating, the present application provides a light-responsive hydrogen-containing silicone oil intelligent coating and a preparation method thereof, which combines the light-responsive monomer, the surface-modified nanoparticles and the hydrogen-containing silicone oil through covalent bond or hydrogen bond, realizes reversible performance regulation of the coating under the irradiation of specific wavelength light, and improves the mechanical stability and service life of the coating.

[0007] In order to solve the above problems, the technical scheme provided by the present application is as follows: a light-responsive hydrogen-containing silicone oil intelligent coating and a preparation method thereof, which comprises a substrate and a functional coating coated on the surface of the substrate, the functional coating is formed by covalent bond or hydrogen bond of hydrogen-containing silicone oil, light-responsive monomer and surface-modified nanoparticles, and the functional coating can change reversibly under the irradiation of specific wavelength light.

[0008] Further, the photoresponsive monomer is a siloxane monomer containing azobenzene groups, and the mass of the photoresponsive monomer accounts for 5%-20% of the total mass of the functional coating.

[0009] Further, the surface-modified nanoparticles are titanium dioxide nanoparticles modified by a silane coupling agent, the particle size is 20-100 nm, and the mass of the surface-modified nanoparticles accounts for 1%-5% of the total mass of the functional coating.

[0010] Further, the following preparation steps are included:

[0011] S1, preparing a photoresponsive monomer: reacting an azobenzene derivative with a siloxane containing a double bond in the presence of a catalyst to obtain a photoresponsive monomer containing azobenzene groups;

[0012] S2, preparing surface-modified nanoparticles: dispersing titanium dioxide nanoparticles in an ethanol solution, adding a silane coupling agent, stirring at 50-80°C for 2-4h, and centrifuging and drying to obtain surface-modified nanoparticles;

[0013] S3, preparing a prepolymer: mixing a hydrogen-containing silicone oil, the photoresponsive monomer prepared in step S1, and the surface-modified nanoparticles prepared in step S2 in a certain proportion, adding a platinum catalyst, and reacting at 60-90°C under nitrogen protection for 3-6h to obtain a prepolymer;

[0014] S4, coating and curing: coating the prepolymer obtained in step S3 on the surface of a substrate, curing under ultraviolet light irradiation for 10-30min to form a photoresponsive hydrogen-containing silicone oil intelligent coating.

[0015] Further, the catalyst in step S1 is dibutyltin dilaurate, and the amount of dibutyltin dilaurate added is 0.1%-0.5% of the total mass of the azobenzene derivative and the siloxane containing a double bond.

[0016] Further, in step S3, the mass ratio of the hydrogen-containing silicone oil, the photoresponsive monomer, and the surface-modified nanoparticles is 100:(10-30):(2-8).

[0017] Further, in step S3, the platinum catalyst is isopropanol solution of chloroplatinic acid, and the amount of platinum element added is 0.001%-0.01% of the total mass of the reaction system.

[0018] Further, in step S4, the wavelength of the ultraviolet light is 365nm, and the irradiation intensity is 5-15mW / cm 2 .

[0019] Further, in step S4, the coating method is spin coating, dip coating, or spray coating, and the coating thickness is 5-50μm.

[0020] Further, the specific wavelength light is ultraviolet light of 300-450 nm or visible light of 450-600 nm, and the reversible performance change includes hydrophilic / hydrophobic change, surface energy change or mechanical property change.

[0021] With the above technical scheme, the light-responsive hydrogen-containing silicone oil intelligent coating and the preparation method have the following advantages:

[0022] 1. Excellent light response performance: By introducing azobenzene group-containing siloxane monomers, the coating can be rapidly and reversibly regulated under ultraviolet / visible light irradiation, with short response time (≤30 s) and good cycle stability (≥50 times).

[0023] 2. Strong interfacial bonding force: The light-responsive monomers are covalently bonded to the hydrogen-containing silicone oil, and the surface-modified nanoparticles are connected to the matrix through hydrogen bonds or covalent bonds, avoiding component shedding and improving the abrasion resistance (abrasion resistance ≥1000 times under a load of 500 g) and weather resistance (performance retention rate ≥90% after 1000 h of ultraviolet aging) of the coating.

[0024] 3. Simple preparation process: The entire preparation process does not require complex equipment, the reaction conditions are mild (temperature ≤90℃, normal pressure), and the coating method is flexible (spin coating, dip coating, and spray coating can be used), which is suitable for large-scale production.

[0025] 4. Wide application range: The coating can be adapted to various substrates such as glass, metal, and polymer, and the performance regulation covers hydrophilic / hydrophobic property, surface energy, and mechanical property, which can be used in intelligent self-cleaning surfaces, light-controlled drug release carriers, self-adaptive electronic device protection, and other fields. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] Embodiment 1

[0028] This embodiment provides a light-responsive hydrogen-containing silicone oil intelligent coating, and the preparation steps are as follows:

[0029] S1, Preparation of photoresponsive monomer: 10 g of 4-hydroxyazobenzene and 12 g of vinyltriethoxysilane were added to a three-necked flask, and after being mixed uniformly, 0.011 g of dibutyltin dilaurate (0.05% of the total mass) was added; under nitrogen protection, 80°C reaction was carried out for 5 h; after cooling, vacuum distillation (vacuum degree 0.09 MPa, temperature 85°C) was carried out to remove the unreacted raw materials, and 18.5 g of light yellow transparent photoresponsive monomer was obtained, with a yield of 92.5%.

[0030] S2, Preparation of surface-modified nanoparticles: 5 g of titanium dioxide nanoparticles with a particle size of 50 nm were taken and dispersed in 50 g of ethanol, and ultrasonic dispersion was carried out for 45 min; 0.5 g of KH560 silane coupling agent was added, and stirring reaction was carried out at 70°C for 3 h; after reaction, centrifugation (9000 r / min, 12 min) was carried out, the precipitate was washed with ethanol for 4 times, and vacuum drying was carried out at 70°C for 5 h, to obtain 4.8 g of surface-modified titanium dioxide nanoparticles, with a particle size test of 52-55 nm.

[0031] S3, Preparation of prepolymer: 100 g of hydrogen-containing silicone oil (hydrogen content 1.0%, viscosity 200 mPa·s), 10 g of photoresponsive monomer of step S1, and 2 g of nanoparticles of step S2 were added to a flask, and stirring was carried out for 20 min; 0.0055 g of platinum catalyst (isopropanol solution of chloroplatinic acid, platinum element accounting for 0.005% of the total mass) was added, and reaction was carried out at 75°C for 4 h under nitrogen protection, to obtain a uniform transparent prepolymer.

[0032] S4, coating and curing: the prepolymer was coated on the surface of a glass substrate by using a spin coating method (rotation speed 3000 r / min, time 30 s); and curing was carried out under 365 nm ultraviolet light (irradiation intensity 10 mW / cm 2 ) for 20 min, to form a coating layer with a thickness of 15 μm.

[0033] Performance test: after ultraviolet light (365 nm) irradiation for 30 s, the water contact angle of the coating layer decreased from 105° to 50°; after visible light (550 nm) irradiation for 60 s, the contact angle rose to 103°; after 50 cycles, the contact angle change amplitude still remained above 95%; the pencil hardness was 2H, which decreased to H after ultraviolet irradiation, and recovered after visible light irradiation; after abrasion test (500 g load, cotton cloth friction) for 1000 times, the coating layer was not damaged.

[0034] Example 2

[0035] The difference between this example and example 1 is that the amount of photoresponsive monomer and the ultraviolet irradiation intensity are adjusted, and the specific steps are as follows:

[0036] S1, Preparation of photoresponsive monomer: same as example 1, to obtain 18.6 g of photoresponsive monomer, with a yield of 93%.

[0037] S2, Preparation of surface-modified nanoparticles: same as Example 1, to obtain 4.7 g of surface-modified titanium dioxide nanoparticles.

[0038] S3, Preparation of prepolymer: mix 100 g of hydrogen-containing silicone oil, 15 g of light-responsive monomer of step S1, 3 g of nanoparticles of step S2, add 0.0059 g of platinum catalyst (0.005% of platinum element in total mass), and react at 75°C for 4 h to obtain a prepolymer.

[0039] S4, Coating and curing: after spin coating (3000 r / min, 30 s), cure under 365 nm ultraviolet light (irradiation intensity 12 mW / cm 2 ) for 15 min to form a coating layer with a thickness of 18 μm.

[0040] Performance test: after ultraviolet light irradiation for 25 s, the contact angle decreases from 102° to 45°; after visible light irradiation for 50 s, it rises to 100°; after 50 cycles, the performance retention rate is 96%; the pencil hardness is 2H, which decreases to H- after ultraviolet irradiation and recovers under visible light; the wear-resistant number is 1200 times without damage.

[0041] Example 3

[0042] The difference between this example and Example 1 is the adjustment of the amount of nanoparticles and the coating method, and the specific steps are as follows:

[0043] S1, Preparation of light-responsive monomer: same as Example 1, to obtain 18.4 g of light-responsive monomer with a yield of 92%.

[0044] S2, Preparation of surface-modified nanoparticles: take 5 g of titanium dioxide nanoparticles with a particle size of 80 nm, disperse in 75 g of ethanol, and ultrasonic for 30 min; add 0.6 g of KH550 silane coupling agent, stir and react at 60°C for 3.5 h; after centrifugal washing, vacuum dry at 75°C for 4.5 h to obtain 4.9 g of surface-modified nanoparticles with a particle size of 82-85 nm.

[0045] S3, Preparation of prepolymer: mix 100 g of hydrogen-containing silicone oil, 20 g of light-responsive monomer of step S1, and 4 g of nanoparticles of step S2, add 0.0062 g of platinum catalyst (0.005% of platinum element in total mass), and react at 80°C for 3.5 h to obtain a prepolymer.

[0046] S4, Coating and curing: use dip coating method (pulling speed 5 mm / s) to coat on the surface of aluminum alloy substrate; cure under 365 nm ultraviolet light (irradiation intensity 8 mW / cm 2 ) for 25 min to form a coating layer with a thickness of 25 μm.

[0047] Performance test: after 35s UV irradiation, the contact angle decreased from 108° to 52°; after 65s visible light irradiation, it increased to 106°; after 50 cycles, the performance retention rate was 94%; pencil hardness was 2H+, which decreased to H after UV irradiation and recovered after visible light irradiation; no corrosion was observed in salt spray test (5% NaCl solution, 48h).

[0048] Example 4

[0049] The difference between this example and Example 1 is the adjustment of reaction temperature and coating thickness, and the specific steps are as follows:

[0050] S1, preparation of light-responsive monomer: 10g of 4-hydroxyazobenzene was mixed with 11g of vinyltriethoxysilane, and 0.0105g of dibutyltin dilaurate (0.05% of the total mass) was added; under nitrogen protection, 85℃ reaction for 4.5h; after reduced pressure distillation, 18.2g of light-responsive monomer was obtained, with a yield of 91%.

[0051] S2, preparation of surface-modified nanoparticles: same as Example 1, 4.8g of surface-modified nanoparticles were obtained.

[0052] S3, preparation of prepolymer: 100g of hydrogen-containing silicone oil, 25g of light-responsive monomer of step S1, 6g of nanoparticles of step S2 were mixed, 0.0068g of platinum catalyst (0.005% of platinum element in total mass) was added, and 85℃ reaction for 3h to obtain the prepolymer.

[0053] S4, coating and curing: using spraying method (pressure 0.3MPa, distance 20cm) to coat on the surface of PET film; 365nm UV light (irradiation intensity 15mW / cm 2 ) curing for 12min to form a coating with a thickness of 30μm.

[0054] Performance test: after 20s UV irradiation, the contact angle decreased from 98° to 42°; after 45s visible light irradiation, it increased to 96°; after 50 cycles, the performance retention rate was 97%; pencil hardness was H+, which decreased to HB after UV irradiation and recovered after visible light irradiation; no cracks were observed in bending test (radius 5mm, 100 times).

[0055] The above describes the present application and its embodiments, which is not restrictive, in general, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, without creative design, similar structure and embodiments to the technical solution, which should belong to the protection scope of the present application.

Claims

1. A photoresponsive hydrogen-containing silicone oil smart coating and a preparation method thereof, characterized in that, The application relates to a functional coating layer and a substrate, wherein the functional coating layer is formed by hydrogen-containing silicone oil, light-responsive monomers and surface-modified nanoparticles through covalent bonds or hydrogen bonds, and the functional coating layer can reversibly change properties under irradiation of specific wavelength light.

2. The coating of claim 1, wherein: The light-responsive monomers are azobenzene group-containing siloxane monomers, and the mass of the light-responsive monomers accounts for 5%-20% of the total mass of the functional coating layer. 3.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 1, wherein: The surface-modified nanoparticles are titanium dioxide nanoparticles modified by a silane coupling agent, the particle size is 20-100 nm, and the mass of the surface-modified nanoparticles accounts for 1%-5% of the total mass of the functional coating layer. ​ 4. The light-responsive hydrogen-containing silicone oil intelligent coating layer and the preparation method thereof according to claim 1 comprise the following preparation steps: S1, preparing light-responsive monomers: reacting azobenzene derivatives and double-bond-containing siloxane under the action of a catalyst to obtain light-responsive monomers containing azobenzene groups; S2, preparing surface-modified nanoparticles: dispersing titanium dioxide nanoparticles in an ethanol solution, adding a silane coupling agent, stirring and reacting at 50-80 DEG C for 2-4 h, and then centrifuging and drying to obtain surface-modified nanoparticles; S3, preparing a prepolymer: mixing hydrogen-containing silicone oil, the light-responsive monomers prepared in step S1 and the surface-modified nanoparticles prepared in step S2 in proportion, adding a platinum catalyst, and reacting at 60-90 DEG C under the protection of nitrogen for 3-6 h to obtain a prepolymer; S4, coating and curing: coating the prepolymer obtained in step S3 on the surface of a substrate, and curing under the irradiation of ultraviolet light for 10-30 min to form a light-responsive hydrogen-containing silicone oil intelligent coating layer. 5.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 4, characterized in that: The catalyst in step S1 is dibutyltin dilaurate, and the addition amount of the catalyst is 0.1%-0.5% of the total mass of azobenzene derivatives and double-bond-containing siloxane. 6.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 4, characterized in that: The mass ratio of hydrogen-containing silicone oil, light-responsive monomers and surface-modified nanoparticles in step S3 is 100:(10-30):(2-8).

7. The method of claim 4, wherein: The platinum catalyst in step S3 is isopropanol solution of chloroplatinic acid, and the addition amount of platinum element is 0.001%-0.01% of the total mass of the reaction system. 8.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 4, characterized in that: The wavelength of the ultraviolet light in the step S4 is 365 nm, and the irradiation intensity is 5-15 mW / cm 2 . 9.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 4, wherein: The coating method in step S4 is spin coating, dip coating or spraying, and the coating thickness is 5-50 mu m. 10.The photo-responsive hydrogen-containing silicone oil smart coating according to claim 1, wherein: The specific wavelength light is ultraviolet light with a wavelength of 300-450 nm or visible light with a wavelength of 450-600 nm, and the reversible property change includes hydrophilic-hydrophobic change, surface energy change or mechanical property change.