CN111299104A

CN111299104A - Super-hydrophobic composite coating and preparation method thereof

Info

Publication number: CN111299104A
Application number: CN202010188538.5A
Authority: CN
Inventors: 鲍艳; 郑茜; 高璐; 强拓; 李雯静; 魏德飞
Original assignee: Shaanxi University of Science and Technology
Current assignee: Shaanxi University of Science and Technology
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2020-06-19
Anticipated expiration: 2040-03-17
Also published as: CN111299104B

Abstract

The invention provides a super-hydrophobic composite coating and a preparation method thereof, comprising the following steps: step 1, ultrasonically dispersing epoxy resin and a curing agent thereof in an organic solvent to form a uniform epoxy resin solution, and then spraying the epoxy resin solution on the surface of a substrate and drying; step 2, ultrasonically dispersing epoxy resin and a curing agent thereof in an organic solvent to form a uniform epoxy resin solution, then adding an inorganic nano filler into the epoxy resin solution, stirring and uniformly dispersing to obtain a mixed solution, and then spraying the mixed solution on the surface of the substrate obtained in the step 1; and 3, ultrasonically dispersing polydimethylsiloxane and a curing agent thereof in an organic solvent to form a uniform polydimethylsiloxane solution, coating the polydimethylsiloxane solution on the surface of the base material obtained in the step 2, drying, and completely curing to obtain the super-hydrophobic composite coating. The method does not need special equipment, is simple to operate and wide in application range, and can greatly improve the super-hydrophobic property of the coating.

Description

Super-hydrophobic composite coating and preparation method thereof

Technical Field

The invention belongs to the field of coatings, and relates to a super-hydrophobic composite coating and a preparation method thereof.

Background

With the development of surface engineering, the super-hydrophobic coating is widely concerned, and is a material surface with a water contact angle of more than 150 ℃ and a rolling angle of less than 10 ℃ and with special functional attributes. In recent years, the super-hydrophobic coating has important application prospects in the fields of self-cleaning, ice coating prevention, corrosion prevention, oil-water separation, bacterial adhesion resistance and the like (Li X M, Reinhoudt D, Crego-Calama M.chemical Society Reviews,2007,36(8): 1350-1368.). At present, two conditions are required for constructing the super-hydrophobic coating: firstly, the material surface has low surface energy substances, and secondly, the surface has a rough structure. For example, Liu et al, which adopts a method combining an etching process and high-temperature calcination to prepare a super-hydrophobic surface on a copper sheet, found that when the etching time is 20h and the calcination temperature is 340 ℃, the micro-nano structure on the surface of the copper sheet is rough, and the micro-nano structure is subjected to hydrophobic modification by stearic acid, so as to finally prepare the super-hydrophobic surface with a contact angle of 157.6 ℃ (Liu W, Xu Q, Han J, et al.Corrosion Science,2016,110: 105-. The Luzhou super class uses polydimethylsiloxane (HTPDMS) modified bisphenol A type epoxy resin as a low surface energy substance and uses micro-nano SiO₂The coating is a nano filler and is cured by adding a compound photoinitiator by adopting an ultraviolet curing technology to obtain a super-hydrophobic coating (Luzhou super, Liuhua, Seisan sand, and the like, Chunbei university journal (Nature science edition), 2019, 39 (4): 386-394). Xu, etc. uses electrochemical deposition as means to form a layer of fluorosilane film on the surface of magnesium alloyObtaining the super-hydrophobic magnesium alloy (Xu W, Song J, Sun J, et al. ACS Applied Materials) with micro-nano coarse structure&Interfaces,2011,3(11): 4404-. However, most of the existing superhydrophobic surfaces need to be prepared by special equipment, have long period and complicated operation, and are difficult to further expand the application.

Disclosure of Invention

The invention aims to provide a super-hydrophobic composite coating and a preparation method thereof, the method does not need special equipment, is simple to operate and wide in application range, and can greatly improve the super-hydrophobic performance of the coating.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a super-hydrophobic composite coating comprises the following steps:

step 1, ultrasonically dispersing epoxy resin and a curing agent thereof in an organic solvent to form a uniform epoxy resin solution, and then spraying the epoxy resin solution on the surface of a substrate and drying;

step 2, ultrasonically dispersing epoxy resin and a curing agent thereof in an organic solvent to form a uniform epoxy resin solution, then adding an inorganic nano filler into the epoxy resin solution, stirring and uniformly dispersing to obtain a mixed solution, and then spraying the mixed solution on the surface of the substrate obtained in the step 1;

and 3, ultrasonically dispersing polydimethylsiloxane and a curing agent thereof in an organic solvent to form a uniform polydimethylsiloxane solution, coating the polydimethylsiloxane solution on the surface of the base material obtained in the step 2, drying, and completely curing to obtain the super-hydrophobic composite coating.

Preferably, in step 1 and step 2, the epoxy resin and the curing agent thereof are epoxy resin E51 and methyl tetrahydrophthalic anhydride, respectively.

Preferably, in step 1 and step 2, the organic solvent is ethyl acetate.

Preferably, in step 1, the substrate is a fabric, leather, glass sheet or metal sheet.

Preferably, in the step 1, the drying temperature is 130-150 ℃, and the drying time is 1.5-2.5 h.

Preferably, in step 2, the inorganic nano-filler is any one of titanium dioxide, zirconium dioxide, zinc oxide and aluminum oxide.

Preferably, in step 3, the polydimethylsiloxane and the curing agent thereof are Sylgard-184A and Sylgard-184B, respectively.

Preferably, in step 3, the organic solvent is any one of n-hexane, tetrahydrofuran and toluene.

Preferably, in the step 3, the drying temperature is 130-150 ℃, and the drying time is 2-6 h.

The super-hydrophobic composite coating obtained by the preparation method.

Compared with other methods, the method has the beneficial technical effects that:

the method comprises the steps of spraying an epoxy resin precoat layer on the surface of a base material, then spraying a nano filler layer, and finally spraying a polydimethylsiloxane layer, wherein the method is simple to operate by adopting a layer-by-layer spraying method, does not need special equipment, can be used for constructing functional super-hydrophobic products such as antifouling fabrics, anticorrosive metals and the like by selecting different base materials and different nano fillers according to the characteristics of the application field, is wide in application range, and is easy to realize large-scale production. The invention firstly takes the epoxy resin as the adhesive, improves the binding force among the nano filler, the resin and the base material by utilizing the self binding action, and particularly forms the epoxy resin coating in a semi-dry state in advance to further enhance the binding force between the coating and the matrix; secondly, nano particles are used as filler, a micro-nano structure is constructed on the surface of the coating, and the hydrophobic property of the coating is improved; finally, the polydimethylsiloxane is used as a low surface energy substance, the hydrophobic property and the bonding effect of the polydimethylsiloxane are utilized, the hydrophobic property of the coating is further improved, and meanwhile, the nano structure can be protected to a certain extent under the friction condition, so that the wear resistance of the super-hydrophobic coating is improved. Therefore, the composite coating prepared by the invention has excellent super-hydrophobic performance (the static water contact angle is more than 155 ℃, and the sliding angle is less than 5 ℃), and still has good hydrophobic property after 20 times of friction.

The super-hydrophobic coating prepared by the method disclosed by the invention is good in wear resistance and excellent in super-hydrophobic property, and is expected to be applied to the fields of self-cleaning, oil-water separation, anti-icing and the like.

Drawings

FIG. 1 is an SEM photograph (magnification: 30000) of ZnO used in examples 1 and 5.

FIG. 2 shows TiO used in example 2₂SEM photograph (magnification 50000 times).

FIG. 3 shows ZrO used in example 3₂SEM photograph (magnification 30000 times).

FIG. 4 shows Al used in example 4₂O₃SEM photograph (magnification is 80000 times)

Fig. 5 is an optical photograph (a), a static water contact angle (b) and a static water contact angle (c) after 20 times of rubbing on 1000 mesh sandpaper with a 100g weight of example 1 to prepare a super-hydrophobic composite coating.

Fig. 6 is an optical photograph (a), a static water contact angle (b), and a static water contact angle (c) after 20 times of rubbing with a 100g weight on 1000 mesh sandpaper of the superhydrophobic composite coating prepared in example 2.

Fig. 7 is an optical photograph (a), a static water contact angle (b), and a static water contact angle (c) after 20 rubs with a 100g weight on 1000 mesh sandpaper of the superhydrophobic composite coating prepared in example 3.

Fig. 8 is an optical photograph (a), a static water contact angle (b), and a static water contact angle (c) after 20 rubs with a 100g weight on 1000 mesh sandpaper of the superhydrophobic composite coating prepared in example 4.

Fig. 9 is an optical photograph (a), a static water contact angle (b), and a static water contact angle (c) after 20 rubs with a 100g weight on 1000 mesh sandpaper of the superhydrophobic composite coating prepared in example 5.

Detailed Description

The super-hydrophobic composite coating and the preparation method thereof according to the present invention are further described below with reference to specific examples.

step (1), ultrasonically dispersing a certain amount of epoxy resin and a curing agent thereof in an organic solvent at room temperature to form a uniform solution, and then spraying the uniform solution on the surface of a substrate and drying the substrate for a period of time;

step (2), ultrasonically dispersing a certain amount of epoxy resin and a curing agent thereof in an organic solvent at room temperature to form a uniform solution, then adding a certain amount of inorganic nano-filler into the solution, magnetically stirring the solution for a certain time to uniformly disperse the inorganic nano-filler, and then spraying the solution on the surface of the base material prepared in the step (1);

and (3) ultrasonically dispersing a certain amount of Polydimethylsiloxane (PDMS) and a curing agent thereof in an organic solvent at room temperature to form a uniform solution, then spraying the uniform solution on the surface of the substrate prepared in the step (2), drying for a period of time, and completely curing to obtain the super-hydrophobic coating.

In the step (1), the epoxy resin and the curing agent are respectively epoxy resin E51 and methyl tetrahydrophthalic anhydride (C)₉H₁₀O₃) The amount of the epoxy resin is 0.05-0.12 g, and the mass ratio of the epoxy resin to the curing agent is 4: 1. The organic solvent is ethyl acetate, and the using amount of the organic solvent is 0.3-0.8 g. The substrate is fabric, leather, glass sheet or metal sheet with an area of about 20cm². The drying temperature is 130-150 ℃, and the drying time is 1.5-2.5 h.

In the step (2), the epoxy resin and the curing agent are respectively epoxy resin E51 and methyl tetrahydrophthalic anhydride (C)₉H₁₀O₃) The amount of the epoxy resin is 0.05-0.15 g, and the mass ratio of the epoxy resin to the curing agent is 4: 1. The organic solvent is ethyl acetate, and the using amount of the organic solvent is 1.0-1.5 g. The inorganic nano filler is TiO₂、ZrO₂ZnO and Al₂O₃Any one of them in an amount of 0.15 to 0.25 g. The stirring time is 1-3 h.

In the step (3), the PDMS and the curing agent thereof are Sylgard-184A and Sylgard-184B respectively, the dosage of the PDMS is 0.01-0.03 g, and the mass ratio of the PDMS to the curing agent is 10: 1. The organic solvent is any one of n-hexane, tetrahydrofuran and toluene, and the using amount of the organic solvent is 0.8-1.5 g. The drying temperature is 130-150 ℃, and the drying time is 2-6 h.

Example 1

Step (1): ultrasonically dispersing 0.07g of epoxy resin E51 and 0.0175g of curing agent methyl tetrahydrophthalic anhydride in 0.5g of ethyl acetate at room temperature to form a uniform solution, then spraying the uniform solution on an aluminum alloy sheet with the thickness of 25mm multiplied by 80mm, and drying the uniform solution at the temperature of 130 ℃ for 2.5 hours;

step (2): ultrasonically dispersing 0.06g of epoxy resin E51 and 0.015g of curing agent methyl tetrahydrophthalic anhydride in 1g of ethyl acetate at room temperature to form a uniform solution, then adding 0.18g of ZnO into the solution, stirring for 2 hours to uniformly disperse the ZnO, and then spraying the ZnO on the surface of the aluminum alloy sheet prepared in the step (1);

and (3): and (3) ultrasonically dispersing 0.01g of PDMS Sylgard-184A and 0.001g of curing agent Sylgard-184B in 1g of n-hexane at room temperature to form a uniform solution, spraying the uniform solution on the surface of the aluminum alloy sheet prepared in the step (2), drying the aluminum alloy sheet at 140 ℃ for 2 hours, and completely curing to obtain the super-hydrophobic coating.

FIG. 1 is an SEM photograph of ZnO used in example 1, showing that ZnO has an irregular rod-like structure and a particle size of about 100 to 800 nm. FIG. 5 is an optical photograph of the prepared super-hydrophobic composite coating (a) showing a static water contact angle (b) and a static water contact angle (c) after friction, and it can be seen that water drops are spherical on the surface of the aluminum alloy, the static water contact angle is 155 ℃ and the rolling angle is 0.8 degrees; the static water contact angle after rubbing was 151.9 °, and the rolling angle was 8.3 °.

Example 2

Step (1): ultrasonically dispersing 0.05g of epoxy resin E51 and 0.0125g of curing agent methyl tetrahydrophthalic anhydride thereof in 0.3g of ethyl acetate at room temperature to form a uniform solution, then spraying the uniform solution on leather with the thickness of 45 x 45mm, and drying the leather at 150 ℃ for 1.5 h;

step (2): 0.08g of epoxy resin E51 and 0.02g of curing agent methyl tetrahydrophthalic anhydride were ultrasonically dispersed in 1.2g of ethyl acetate at room temperature to form a homogeneous solution, and 0.2g of TiO was added thereto₂Stirring for 2 hours, and then spraying the mixture on the surface of the leather prepared in the step (1);

and (3): and (3) ultrasonically dispersing 0.015g of PDMS Sylgard-184A and 0.0015g of curing agent Sylgard-184B thereof in 0.8g of n-hexane at room temperature to form a uniform solution, spraying the uniform solution on the surface of the leather prepared in the step (2), drying the uniform solution at 130 ℃ for 5 hours, and completely curing to obtain the super-hydrophobic coating.

FIG. 2 shows TiO used in example 2₂The SEM photograph of (1) shows that TiO was present₂Is irregular granular and has the grain diameter of about 80-500 nm. FIG. 6 shows an optical photograph (a), a static water contact angle (b) and a static water contact angle (c) after rubbing of the prepared super-hydrophobic composite coating, wherein it can be seen that water drops are spherical on the surface of leather, the static water contact angle is 166 ℃, and the rolling angle is 1.1 degrees; the static water contact angle after rubbing is 149.3 degrees, and the rolling angle is 7.5 degrees.

Example 3

Step (1): ultrasonically dispersing 0.1g of epoxy resin E51 and 0.025g of curing agent methyl tetrahydrophthalic anhydride in 0.7g of ethyl acetate solution at room temperature to form a uniform solution, then spraying the uniform solution on 45mm × 45mm fabric and drying the uniform solution at 140 ℃ for 2 hours;

step (2): 0.05g of epoxy resin E51 and 0.0125g of its hardener, methyltetrahydrophthalic anhydride, were dispersed ultrasonically in 1.5g of ethyl acetate at room temperature to form a homogeneous solution, after which 0.25g of ZrO was added thereto₂Stirring for 3 hours, and then spraying the mixture on the surface of the fabric prepared in the step (1);

and (3): and (3) ultrasonically dispersing 0.02g of PDMS Sylgard-184A and 0.002g of curing agent Sylgard-184B thereof in 1.5g of tetrahydrofuran at room temperature to form a uniform solution, then spraying the uniform solution on the surface of the fabric prepared in the step (2), drying the surface at 150 ℃ for 3 hours, and completely curing to obtain the super-hydrophobic coating.

FIG. 3 shows ZrO used in example 3₂The SEM photograph of (1) shows ZrO₂The particles are extremely small, and the agglomeration phenomenon is serious. FIG. 7 is an optical photograph (a), a static water contact angle (b) and a static water contact angle (c) after rubbing of the prepared super-hydrophobic composite coating, and it can be seen that water drops are spherical on the surface of the fabric, the static water contact angle is 157 ℃ and the rolling angle is 2.8 degrees; the static water contact angle after rubbing was 148.4 ° and the rolling angle was 16.1 °.

Example 4

Step (1): ultrasonically dispersing 0.12g of epoxy resin E51 and 0.03g of curing agent methyl tetrahydrophthalic anhydride in 0.8g of ethyl acetate solution at room temperature to form a uniform solution, then spraying the uniform solution on a glass sheet with the thickness of 25mm multiplied by 75mm, and drying the glass sheet at the temperature of 140 ℃ for 2 hours;

step (2): 0.15g of epoxy resin E51 and 0.0375g of curing agent methyl tetrahydrophthalic anhydride were ultrasonically dispersed in 1g of ethyl acetate at room temperature to form a homogeneous solution, and 0.15g of Al was added thereto₂O₃Stirring for 1h, and then spraying the mixture on the surface of the glass prepared in the step (1);

and (3): and (3) ultrasonically dispersing 0.03g of PDMS Sylgard-184A and 0.003g of curing agent Sylgard-184B in 1g of n-hexane at room temperature to form a uniform solution, then spraying the uniform solution on the glass surface prepared in the step (2), drying the glass surface at 145 ℃ for 6 hours, and completely curing to obtain the super-hydrophobic coating.

FIG. 4 shows Al used in example 4₂O₃In the SEM photograph, Al was found₂O₃The size is very small, but the agglomeration phenomenon is severe. Fig. 8 is an optical photograph (a), a static water contact angle (b) and a static water contact angle (c) after friction of the prepared super-hydrophobic composite coating, and it can be seen that water drops are spherical on the surface of the glass, the static water contact angle is 167 degrees, and the rolling angle is 1.3 degrees; the static water contact angle after rubbing is 150.2 degrees, and the rolling angle is 11.8 degrees.

Example 5

Step (1): ultrasonically dispersing 0.08g of epoxy resin E51 and 0.02g of curing agent methyl tetrahydrophthalic anhydride in 0.7g of ethyl acetate at room temperature to form a uniform solution, then spraying the uniform solution on 45mm × 45mm fabric and drying the uniform solution at 150 ℃ for 1.5 h;

step (2): ultrasonically dispersing 0.06g of epoxy resin E51 and 0.015g of curing agent methyltetrahydrophthalic anhydride in 1g of ethyl acetate at room temperature to form a uniform solution, then adding 0.18g of ZnO into the uniform solution, stirring the mixture for 2 hours, and then spraying the mixture on the surface of the fabric prepared in the step (1);

and (3): and (3) ultrasonically dispersing 0.013g of PDMS Sylgard-184A and 0.0013g of curing agent Sylgard-184B into 1g of n-hexane at room temperature to form a uniform solution, spraying the uniform solution on the surface of the fabric prepared in the step (2), drying the fabric at 150 ℃ for 2 hours, and completely curing to obtain the super-hydrophobic coating.

Fig. 1 is an SEM photograph of ZnO used in example 5, and fig. 9 is an optical photograph (a), a static water contact angle (b) and a static water contact angle (c) after rubbing of the prepared superhydrophobic composite coating, and it can be seen that water drops are spherical on the surface of the fabric, the static water contact angle is 159 ° and the rolling angle is 1.7 °; the static water contact angle after rubbing was 152.8 °, and the rolling angle was 17.4 °.

Table 1 shows the sliding angles of the coatings prepared in examples 1-5 and the sliding angles of the coatings after 20 times of rubbing, and from FIGS. 5-9 and Table 1, it can be seen that the composite coating prepared by the invention has excellent super-hydrophobic property (the static water contact angle is more than 155 ℃, the sliding angle is less than 5 ℃) and has good hydrophobic property after 20 times of rubbing.

TABLE 1 sliding angles of the coatings prepared in examples 1 to 5 and their sliding angles after 20 rubs

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.

Claims

1. A preparation method of a super-hydrophobic composite coating is characterized by comprising the following steps:

2. The method for preparing the superhydrophobic composite coating according to claim 1, wherein in step 1 and step 2, the epoxy resin and the curing agent thereof are epoxy resin E51 and methyl tetrahydrophthalic anhydride, respectively.

3. The method for preparing the superhydrophobic composite coating of claim 1, wherein the organic solvent is ethyl acetate in step 1 and step 2.

4. The method for preparing the superhydrophobic composite coating of claim 1, wherein in the step 1, the substrate is a fabric, leather, a glass sheet or a metal sheet.

5. The preparation method of the superhydrophobic composite coating according to claim 1, wherein in the step 1, the drying temperature is 130-150 ℃ and the drying time is 1.5-2.5 hours.

6. The method for preparing the superhydrophobic composite coating of claim 1, wherein in the step 2, the inorganic nano-filler is any one of titanium dioxide, zirconium dioxide, zinc oxide and aluminum oxide.

7. The method for preparing the superhydrophobic composite coating of claim 1, wherein in the step 3, the polydimethylsiloxane and the curing agent thereof are Sylgard-184A and Sylgard-184B, respectively.

8. The method for preparing the superhydrophobic composite coating of claim 1, wherein in the step 3, the organic solvent is any one of n-hexane, tetrahydrofuran and toluene.

9. The preparation method of the superhydrophobic composite coating according to claim 1, wherein in the step 3, the drying temperature is 130-150 ℃ and the drying time is 2-6 hours.

10. The super-hydrophobic composite coating obtained by the preparation method of any one of claims 1 to 9.