CN105038338B - Transparent hydrophobic spray and its preparation method and application - Google Patents

Abstract

The invention provides a transparent super-hydrophobic spray and its preparation method and application. The transparent super-hydrophobic spray is colorless and transparent, and is liquid at normal temperature. A layer of transparent super-hydrophobic can be formed by spraying on the surface of a substrate. Film, the transparent superhydrophobic film formed by the transparent superhydrophobic spray has a contact angle of not less than 150°, a rolling angle of less than 10°, is transparent in the visible light region, and has a light transmittance of 90-99% at 550nm. The transparent superhydrophobic spray provided by the invention is easy to use, and can be widely used in the hydrophobic treatment of the surfaces of ceramics, glass, paper, wood, stone, metal, or polymer materials.

Description

Transparent superhydrophobic spray and its preparation method and application

technical field

The invention relates to a transparent superhydrophobic film material, in particular to a transparent superhydrophobic spray and its preparation method and application.

Background technique

Transparent superhydrophobic film is a new type of film material developed after superhydrophobic coating. It has the characteristics of transparency and super-hydrophobicity, and has great application potential in microfluidics, anti-fouling, anti-corrosion, oil-water separation, etc. Its transparent and super-hydrophobic properties are used in fields such as solar panel self-cleaning, fabric antifouling, bridge anticorrosion, and oil pollution treatment. It can be seen that the transparent superhydrophobic film material will show its important application value in various fields with its excellent performance in the future.

Typical superhydrophobic films are generally divided into three categories according to transparency: one is called opaque superhydrophobic film, the second is called translucent superhydrophobic film, and the third is called transparent superhydrophobic film. Superhydrophobic silicon dioxide film, transparent superhydrophobic zinc oxide film, etc. Because silica is stable under ultraviolet light and easy to prepare, it is often used in various ways to prepare superhydrophobic coatings. In terms of chemical properties, because there are a large number of hydroxyl groups on the surface of silica, various hydrophobic groups can be grafted, so their surface energy can be adjusted according to the grafted groups; as for physical properties, silica Has good high temperature stability. In addition, when the silicon dioxide particle size is less than 100nm, it shows a high degree of transparency. By adjusting the thickness of the silicon dioxide film, it can even have the function of anti-reflection.

The sol-gel method is currently one of the main methods for synthesizing nano-sized silica. It is called the Sol-Gel method in industrial production. The traditional method is to use ethyl orthosilicate as the silicon source and perfluorosilane as the modifier. . It can be seen that the modifier perfluorosilane used in this method is not easy to decompose in the natural environment, so it is very harmful to the environment, and the price of perfluorosilane is expensive, which is not conducive to civilian production.

Contents of the invention

The purpose of the present invention is to provide a transparent super-hydrophobic spray with good hydrophobic performance and high visible light transmittance and its preparation method and application.

In order to achieve the above object, the present invention discloses a transparent super-hydrophobic spray on the one hand, comprising surface-modified _SiO2 nanoparticles and a dispersion medium, wherein the surface-modified _SiO2 chemical structural formula is as follows: Among them, the It is a bulk structure, R ₁ and R ₂ are Si(CH ₃ ) ₃ or Si(CH ₂ CH ₃ ) ₃ , n ₁ =10 ⁵ to 10 ⁹ , n ₂ =10 ⁵ to 10 ⁹ , m=10 ³ to 10 ⁷ ; the dispersion medium is one or more of methanol, ethanol, n-propanol, isopropanol, n-hexane, and n-heptane.

The second aspect of the present invention provides a kind of preparation method of transparent superhydrophobic spray, it comprises the following steps:

(1) Preparation of sol: provide tetraethyl orthosilicate solution A and alkaline solution B, mix to obtain mixed solution C, add acidic solution, adjust PH to 1～3, and react to obtain silica sol with a solid content of 5- 30% silica sol;

(2) Preparation of gel: adding alkaline solution B to the silica sol obtained in step (1) to make its pH value 8-10 to obtain transparent silica gel;

(3) Modification of the gel: Mix the modifier with the dispersion medium to obtain the mixed solution D, and add the mixed solution D to the silica gel obtained in step (2), and react at 30-80°C for 1-24h , to obtain an alkylated silica gel;

(4) Dispersion of the gel and preparation of the spray: add a dispersion medium to the alkylated silica gel obtained in step (3), wash and disperse to obtain a dispersion, settle, and separate the supernatant to obtain Color transparent spray.

The third aspect of the present invention provides the application of the transparent superhydrophobic spray of the first aspect of the present invention, which includes the following steps: spraying the transparent superhydrophobic spray on a clean and dry substrate, and then heating it with 40-120°C Air blowing can form a layer of transparent super-hydrophobic film on the surface of the substrate.

The beneficial effects of the present invention are: the transparent superhydrophobic spray is colorless and transparent, and is in a liquid state at room temperature, and a layer of transparent superhydrophobic film can be formed by spraying on the surface of the substrate. High efficiency, easy to use, can be widely used in the hydrophobic treatment of ceramics, glass, paper, wood, stone, metal, or polymer surfaces.

Description of drawings

Fig. 1 is the field emission scanning electron microscope picture of the transparent superhydrophobic coating obtained in embodiment one.

Fig. 2 is the transparent performance test diagram of the transparent superhydrophobic coating obtained in embodiment one.

detailed description

Shown in Fig. 1, the present invention discloses a kind of transparent superhydrophobic spray on the one hand, comprise the SiO of surface modification Nanoparticle and dispersion medium, wherein, the SiO of described surface modification Molecular _formula /chemical structural _formula are as follows: Among them, the It is a bulk structure, R ₁ and R ₂ are Si(CH ₃ ) ₃ or Si(CH ₂ CH ₃ ) ₃ , n ₁ =10 ⁵ to 10 ⁹ , n ₂ =10 ⁵ to 10 ⁹ , m=10 ³ to 10 ⁷ ; the dispersion medium is one or more of methanol, ethanol, n-propanol, isopropanol, n-hexane, and n-heptane.

Preferably, the mass percent of the surface-modified SiO ₂ is 0.01-0.5%.

Preferably, the particle size of the surface-modified SiO ₂ nanoparticles is 10-100 nm.

The second aspect of the present invention provides a kind of preparation method of transparent superhydrophobic spray, it comprises the following steps:

(1) Preparation of sol: provide tetraethyl orthosilicate solution A and alkaline solution B, mix to obtain mixed solution C, add acidic solution, adjust PH to 1～3, and react to obtain silica sol with a solid content of 5- 30% silica sol;

(2) Preparation of gel: adding alkaline solution B to the silica sol obtained in step (1) to make its pH value 8-10 to obtain transparent silica gel;

(3) Modification of the gel: Mix the modifier with the dispersion medium to obtain the mixed solution D, and add the mixed solution D to the silica gel obtained in step (2), and react at 30-80°C for 1-24h , to obtain an alkylated silica gel;

(4) Dispersion of the gel and preparation of the spray: add a dispersion medium to the alkylated silica gel obtained in step (3), wash and disperse to obtain a dispersion, settle, and separate the supernatant to obtain Color transparent spray.

Preferably, the modifying agent includes at least one of trimethylmonochlorosilane, triethylchlorosilane and hexamethyldisilazane. Further preferably, the dispersion medium includes at least one of methanol, ethanol, n-propanol, isopropanol, n-hexane and n-heptane. The modified hydrophobic silica can be stably dispersed in methanol, ethanol, n-propanol, isopropanol, n-hexane, and n-heptane, and the dispersion medium is volatile, which greatly reduces the film-forming temperature. More preferably, in the step (3), the weight ratio of the modifier to the dispersion medium is 1:1-15. Still further preferably, in the step (3), the mass ratio of the mixed liquid D to the silica gel is 1:1-3.5. More preferably, in the step (4), the dispersion medium is added in two steps, the dispersion medium in the first step is at least one of methanol, ethanol, n-propanol and isopropanol, and the silica gel The mass ratio of silica gel to dispersion medium is 1:2-8; in the second step, the dispersion medium is at least one of n-hexane and n-heptane, and the mass ratio of silica gel to dispersion medium is 1:3-20. Still further preferably, in the step (4), the settling temperature is -10°C-30°C, and the time is 0.5-30 days.

Preferably, at least one of ethanol, methanol, n-propanol or isopropanol is used as a solvent for the tetraethyl orthosilicate solution A and the alkaline solution B.

Preferably, the solute in the alkaline solution B is ammonia, and the solute in the acidic solution is hydrochloric acid.

The third aspect of the present invention provides the application of the transparent superhydrophobic spray of the first aspect of the present invention, which comprises the following steps: spraying the transparent superhydrophobic spray on a clean, dry substrate, drying, and then A transparent super-hydrophobic film is formed on the surface. Specifically, the drying process may use hot air blowing at 40-120°C.

Preferably, the base material is selected from any one of ceramics, glass, paper, wood, stone, metal, or polymer.

Preferably, the contact angle of the transparent superhydrophobic film is not less than 150°, and the rolling angle is less than 10°.

Preferably, the transparent super-hydrophobic film is transparent in the visible light region, and the 550nm light transmittance is 90-99%.

The transparent superhydrophobic spray of the present invention and its preparation method and application are described in detail below in conjunction with the examples.

Embodiment one

(1) Mix 4.7g ethyl orthosilicate and 7.9g methanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. Add 3.5 g of 0.1 mol/L hydrochloric acid to the mixed solution C, and then ultrasonicate at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate is 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) Mix 8 g of triethylchlorosilane and 48.5 g of n-hexane evenly to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60 g of n-heptane to the dispersion, and then ultrasonicate at 50 Hz for 0.5 h. The obtained liquid is placed at -10 ° C for three days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of the glass slide, and then dry the substrate with hot air at 120°C for multiple cycles to obtain a transparent super-hydrophobic surface.

The microstructure of the final transparent superhydrophobic coating was observed by a JSM7100F field emission scanning electron microscope, and the photo shown in Figure 1 was obtained. From Figure 1, it can be seen that the prepared transparent superhydrophobic coating is dense and the particles are arranged regularly.

The visible light transmittance is tested by a UV-3600 UV-Vis spectrophotometer on the glass slide before and after the transparent super-hydrophobic coating, and the curve shown in Figure 2 is obtained. As can be seen from Figure 2, the transparent super-hydrophobic coating is coated with The 350-800nm visible light transmittance of the front and rear glass slides remains basically unchanged, and the visible light transmittance is >85%.

Embodiment two

(1) Mix 4.7g ethyl orthosilicate and 7.9g ethanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. Add 3.5 g of 0.1 mol/L hydrochloric acid to the mixed solution C, and then ultrasonicate at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate is 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) Mix 6.5 g of trimethylchlorosilane and 48.5 g of n-hexane evenly to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60 g of n-heptane to the dispersion, and then ultrasonicate at 50 Hz for 0.5 h. The obtained liquid is placed at -10 ° C for three days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of the tiles, then dry the substrate with hot air at 100°C, and repeat the cycle several times to obtain a transparent super-hydrophobic surface.

Embodiment three

(1) Mix 4.7g ethyl orthosilicate and 7.9g ethanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. 3.5 g of 0.1 mol/L hydrochloric acid was added to the mixed solution C, and then ultrasonicated at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate was 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) 5.8 g of hexamethyldisilazane and 48.5 g of n-hexane were uniformly mixed to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60g of n-heptane to the dispersion, and then ultrasonicate at 50Hz for 0.5h. The obtained liquid is placed at 0°C for 5 days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of A4 paper, then dry the substrate with 80°C hot air, and repeat it several times to obtain a transparent super-hydrophobic surface.

Embodiment Four

(1) Mix 4.7g ethyl orthosilicate and 7.9g ethanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. Add 3.5 g of 0.1 mol/L hydrochloric acid to the mixed solution C, and then sonicate at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate is 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) 5.8 g of hexamethyldisilazane and 48.5 g of n-hexane were uniformly mixed to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60 g of n-heptane to the dispersion liquid, and then ultrasonicate at 50 Hz for 0.5 h. The obtained liquid is placed at 20° C. for 15 days, settles, and finally separates the supernatant liquid to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of the wood, then dry the substrate with hot air at 60°C, and repeat it several times to obtain a transparent super-hydrophobic surface.

Embodiment five:

(1) Mix 4.7g ethyl orthosilicate and 7.9g n-propanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. 3.5 g of 0.1 mol/L hydrochloric acid was added to the mixed solution C, and then ultrasonicated at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate was 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) 5.8 g of hexamethyldisilazane and 48.5 g of n-hexane were uniformly mixed to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60g of n-heptane to the dispersion, and then ultrasonicate at 50Hz for 0.5h. The obtained liquid is placed at 30°C for 30 days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of the plexiglass, then dry the substrate with hot air at 40°C, and repeat it several times to obtain a transparent super-hydrophobic surface.

Embodiment six

(1) Mix 4.7g tetraethyl orthosilicate and 7.9g isopropanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. 3.5 g of 0.1 mol/L hydrochloric acid was added to the mixed solution C, and then ultrasonicated at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate was 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) 5.8 g of hexamethyldisilazane and 48.5 g of n-hexane were uniformly mixed to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) washing the alkylated silica gel with n-hexane and n-propanol, adding 20 g of n-propanol to the washed alkylated silica gel, and ultrasonicating at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60 g of n-heptane to the dispersion, and then ultrasonicate at 50 Hz for 0.5 h. The obtained liquid is placed at -10 ° C for three days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the surface of the copper sheet, then dry the substrate with hot air at 120°C, and repeat it several times to obtain a transparent super-hydrophobic surface.

Embodiment seven

(1) Mix 4.7g ethyl orthosilicate and 7.9g ethanol uniformly to obtain mixed solution A; mix 7.5g 0.02mol/L ammonia water and 7.9g ethanol uniformly to obtain mixed solution B. Mix mixed solution A and mixed solution B evenly to obtain mixed solution C. Add 3.5 g of 0.1 mol/L hydrochloric acid to the mixed solution C, and then ultrasonicate at 50 Hz for 2 hours to obtain a sol precursor, and the silicon dioxide content of ethyl orthosilicate is 28%;

(2) adding ammonia water with a mass fraction of 25%-28% to the sol precursor under the condition of high-speed stirring, so that the pH value is 8-10, and a transparent gel precursor is obtained;

(3) 5.8 g of hexamethyldisilazane and 48.5 g of n-hexane were uniformly mixed to obtain a mixed liquid D. Add the mixed solution D to the gel precursor and react at 60°C for 16 hours to obtain an alkylated silica gel;

(4) Wash the alkylated silica gel with n-hexane and ethanol, add 16 g of ethanol to the washed alkylated silica gel, and sonicate at 50 Hz for 1 h to obtain a dispersion;

(5) Add 60 g of n-heptane to the dispersion, and then ultrasonicate at 50 Hz for 0.5 h. The obtained liquid is placed at -10 ° C for three days, settles, and finally separates the supernatant to obtain a colorless and transparent spray;

(6) Spray the spray on the glass surface, then dry the substrate with hot air at 120°C, and repeat it several times to obtain a transparent super-hydrophobic surface.

The inventor tested the samples prepared in Examples 1, 5, and 7 of the present invention and the samples prepared in Chinese patents CN201210122274.9, CN201410407416.5, and CN201410652035.3 in a Dataphysics OCA20 contact angle measuring instrument, respectively. rolling angle, and tested the visible light transmittance with a wavelength of 350-800nm by a UV-3600 type ultraviolet-visible spectrophotometer, and obtained the results shown in Table 1:

Table 1:

It can be seen from Table 1 that the hydrophobic film formed by the transparent superhydrophobic spray of the present invention has a higher surface contact angle, a lower rolling angle, and a significant increase in visible light transmittance.

Claims (9)

1. a kind of modified SiO of transparent hydrophobic spray, including surface₂Nano-particle and decentralized medium, wherein, The modified SiO in the surface₂Chemical structural formula is as follows：Wherein, it is describedIt is three-dimensional-structure, R₁、R₂It is Si (CH₃)₃Or Si (CH₂CH₃)₃, n₁=10⁵~10⁹, n₂= 10⁵~10⁹, m=10³~10⁷；The decentralized medium is in methyl alcohol, ethanol, normal propyl alcohol, isopropanol and n-hexane, normal heptane One or more；

The surface is modified SiO₂Nano particle diameter is 10-100nm.

2. transparent hydrophobic spray as claimed in claim 1, it is characterised in that：The surface is modified SiO₂Nano-particle quality Percentage is 0.01-0.5%.

3. a kind of preparation method of transparent hydrophobic spray as claimed in claim 1, it is comprised the following steps：

(1) preparation of colloidal sol：Teos solution A and alkaline solution B is provided, mixed liquor C is obtained after mixing, add acid molten Liquid, regulation pH is 1~3, and reaction obtains the silicon dioxide gel that silicon dioxide gel solids content is 5-30%；

(2) preparation of gel：To alkaline solution B is added in the silicon dioxide gel that step (1) is obtained, make its pH value for 8-10, Obtain transparence silica dioxide gel；

(3) gel is modified：Modifying agent and decentralized medium are mixed to get mixed liquor D, and add step (2) to obtain mixed liquor D To silica dioxide gel in, react 1-24h at 30-80 DEG C, the silica dioxide gel being alkylated；

(4) dispersion of gel and the preparation of spray：Dispersion is added to be situated between in the silica dioxide gel of the alkylation obtained to step (3) Matter, washing, dispersion obtains dispersion liquid, settles, and separates supernatant liquor and obtains colorless and transparent spray.

4. preparation method as claimed in claim 3, it is characterised in that：The modifying agent includes tri-methyl-chlorosilane, three second At least one in base chlorosilane and HMDS.

5. preparation method as claimed in claim 4, it is characterised in that：The decentralized medium include methyl alcohol, ethanol, normal propyl alcohol, At least one in isopropanol and n-hexane, normal heptane.

6. preparation method as claimed in claim 5, it is characterised in that：In the step (3), the weight of modifying agent and decentralized medium Amount is than being 1：1-15.

7. preparation method as claimed in claim 6, it is characterised in that：In the step (3), mixed liquor D coagulates with silica The mass ratio of glue is 1：1-3.5.

8. preparation method as claimed in claim 4, it is characterised in that：In the step (4), the decentralized medium adds in two steps Enter, decentralized medium is at least one in methyl alcohol, ethanol, normal propyl alcohol and isopropanol, silica dioxide gel and dispersion in the first step The mass ratio of medium is 1：2-8；Decentralized medium is at least one in n-hexane and normal heptane, silica dioxide gel in second step It is 1 with decentralized medium mass ratio：3-20.

9. the application of transparent hydrophobic spray as claimed in claim 1, it is comprised the following steps：By transparent hydrophobic spray Agent is sprayed in clean, dry substrate, drying, you can form layer of transparent based superhydrophobic thin films in substrate surface.