CN110434034A - Preparation method of super-hydrophobic coating - Google Patents

Abstract

The invention relates to a method for preparing a super-hydrophobic coating. The etching method in the invention uses three different immersion solutions to immerse for a period of time, so that the etching rate can be accelerated by using different immersion solutions. The proportion of the liquid can speed up the etching rate. By speeding up the etching rate, the amount of side etching and the edge can be reduced. The micro-nano morphology formed on the surface of the copper sheet is more complex, which increases the hydrophobicity, friction resistance and durability of the super-hydrophobic coating. Bending resistance: the present invention selects two kinds of fluorosilanes and silanes with similar boiling points, which can be better deposited on the surface of the etched substrate copper, so that the coating has a very low surface energy, the coating quality is relatively stable, and good hydrophobicity is achieved. The effect makes the corrosion resistance and cleaning performance of copper better, and the service life is longer.

Description

A kind of preparation method of superhydrophobic coating

technical field

The invention belongs to the technical field of superhydrophobic materials, and in particular relates to a preparation method of a superhydrophobic coating.

Background technique

Because of its thermal conductivity, electrical conductivity, corrosion resistance and processing properties, copper has important applications in various industries such as electric power, marine and military industries. For example, most of the condensers in the power industry, the heat exchange devices of low-pressure heating and oil coolers, and the hollow wires of water-cooled generators are made of copper alloy materials; in the marine military industry, in the water piping systems of military warships such as aircraft carriers Most of them are some copper materials; civil medical equipment, industrial utensils, telecommunications industry parts, etc. have copper applications. However, the application of copper has been limited due to the serious corrosion problems exposed by copper materials during use.

Superhydrophobic surface treatment technology is a new anti-corrosion technology. Superhydrophobic surface can self-clean, inhibit surface corrosion and surface oxidation, and reduce friction coefficient for metal materials. It should be noted that the super-hydrophobic surface is a common natural phenomenon in nature. For example, when water drops on the lotus leaf, the water and the lotus leaf form a contact angle close to 170°, aggregate into beads without spreading, and are extremely hydrophobic. Water droplets can roll freely on the surface of the lotus leaf. When the water droplets (such as rain, dew, etc.) roll, they can take away the dust and other pollutants attached to the surface, so that the surface can be kept clean. Such a surface is called the lotus leaf effect. surface, also known as superhydrophobic surface.

There are many preparation methods for hydrophobic surfaces, and chemical etching methods, electrochemical methods, and photolithography methods are commonly used at home and abroad. In the final analysis, the etching process is an operation that damages the surface of the substrate, especially for thin-layer aluminum alloy substrates, the mechanical properties will be greatly affected during the etching process, and even lead to cracks or breakage of the substrate. The rate is low, and the micro-nano morphology of the surface of the copper sheet in the existing etching method is simple, so that the prepared hydrophobic coating has problems such as poor hydrophobic effect, poor wear resistance and bending resistance.

In view of the above reasons, the present invention is proposed.

Contents of the invention

In order to solve the above problems in the prior art, the present invention provides a method for preparing a superhydrophobic coating. The etching method of the present invention can accelerate the etching rate of the copper sheet, reduce the amount of side etching and the edge, and the surface formed The micro-nano structure is more complex, which can increase the hydrophobicity, wear resistance and bending resistance of the superhydrophobic coating.

In order to achieve the above object, the present invention adopts the following technical solutions:

A kind of preparation method of superhydrophobic coating, described method comprises the steps:

(1) Substrate pretreatment: select copper sheets for derusting, ultrasonically clean them with acetone, ethanol, and deionized water in turn, and dry them for later use;

(2) copper sheet etching: immerse the pretreated copper sheet in the etching solution and react for 12-24h, wash three times with deionized water, and dry for subsequent use;

(3) Put the fluorosilane, silane and etched copper sheet into the reaction kettle for the first heating, cool to room temperature, put it into the oven for the second heating, and form a superhydrophobic coating on the surface of the copper sheet.

Further, the copper sheets in the step (1) are polished and derusted through 400-mesh, 600-mesh, 1000-mesh, 1500-mesh, and 2000-mesh sandpaper in sequence.

Further, the etching described in the step (2) is to first immerse the copper sheet in the mixed solution of sodium chloride and hydrochloric acid for 4-8h, clean it with deionized water, dry it, and then immerse it in the mixture of hydrogen peroxide and hydrochloric acid. Put it in the mixed solution for 4-10 hours, wash it with deionized water, dry it in the air, and then immerse it in the mixed solution of ferric chloride and hydrochloric acid for 4-6 hours.

The etching method in the present invention uses three different immersion solutions to immerse for a period of time respectively,

By immersing the substrate in different specific proportions of mixed etching solutions and increasing the stirring in different directions, not only can the etching rate be accelerated, the amount of side etching, edge protrusion and local etching can be avoided, but also a very complex composite microstructure can be obtained. The nanostructure forms a suitable roughness on the surface of the substrate, so that the surface is not only distributed with a strip-shaped groove array, the depth and size of the groove are irregular, but also uniformly distributed with many tiny granular papillae and micropores. There are tiny grooves of different sizes on the raised blocks, which is beneficial to reduce the contact area between water and the substrate, and lay a solid foundation for the construction of super-hydrophobic coatings.

In order to avoid local etching and edge etching of the copper sheet, and to make the substrate etch uniformly, the etchant is etched vertically or horizontally and ultrasonically during the etching process. When stirring vertically, put the etching solution and copper sheet into a three-neck round bottom flask, fix it in the iron stand, place the stirring rod vertically above the copper sheet, adjust the stirring speed at 200-270r/min, increase the stirring rate to increase the etching rate . When stirring horizontally, put the etching solution and copper sheet into the beaker, fix an iron stand that can rotate left and right next to the ultrasonic machine, place the stirring rod horizontally, and the stirring rate is 150-200r/min. etch more uniformly.

Further, the mixed solution of sodium chloride and hydrochloric acid is obtained by mixing equal volumes of aqueous sodium chloride solution with a concentration of 1-2 mol/L and hydrochloric acid solution with a mass fraction of 10-20%.

Further, the mixed solution of hydrogen peroxide and hydrochloric acid is obtained by mixing equal volumes of hydrogen peroxide with a mass fraction of 14-16% and hydrochloric acid solution with a mass fraction of 10-20%.

Further, the mixed solution of ferric chloride and hydrochloric acid is obtained by mixing equal volumes of an aqueous ferric chloride solution with a mass fraction of 5-10% and a hydrochloric acid solution with a mass fraction of 30-40%.

Further, the volume ratio of fluorosilane and silane in step (3) is 1:1-2.

Further, the fluorosilane is tridecafluorozincyltriethoxysilane, and the silane is octadecyltrimethoxysilane.

Further, the temperature of the first heating in step (3) is 130-140° C., and the heating time is 3-4 hours.

Further, the temperature of the second heating in step (3) is 165-170°C, and the heating time is 1.8-2.2h.

The purpose of the first heating is to make the liquid fluorosilane and silane gaseously deposited on the surface of the copper sheet, and the purpose of the second heating is to volatilize the excess liquid fluorosilane and silane on the surface of the copper sheet.

Compared with prior art, the beneficial effect of the present invention is:

(1) The etching method in the present invention uses three different immersion solutions to immerse for a period of time respectively, and the matrix can not only accelerate the etching rate by immersing in different specific proportions of mixed etching solutions and increase stirring in different directions, Reduce the amount of side etching, edge protrusion and avoid local etching, and can also obtain a very complex composite micro-nano structure, forming a suitable roughness on the surface of the substrate, so that the surface is distributed with strip-shaped groove arrays, grooves The depth and size are irregular, and there are many tiny granular papillae and micropores evenly distributed, and there are tiny ravines of different sizes on the raised blocks, which is beneficial to reduce the contact area between water and the matrix, and is useful for the construction of super The hydrophobic coating lays a solid foundation; increases the complexity of the micro-nano morphology formed on the surface of the copper sheet, and increases the hydrophobicity, friction resistance and bending resistance of the super-hydrophobic coating;

(2) The present invention selects two kinds of fluorosilanes and silanes with similar boiling points, which can be better deposited on the copper surface of the etched substrate, and form a stable, super-hydrophobic coating on the surface. Fluorosilane and silane The alkoxyl groups in the water environment undergo gradual hydrolysis to form highly active silanol groups that can form perfect hydrogen bonds with the silanol groups adsorbed on the surface of metal copper, and the silanol groups can also undergo dehydration reactions with each other to form oligomer Si -O-Si, the unreacted silicon hydroxyl group and the excess hydroxyl group on the copper surface are covalently bonded, and the thin layer of fluorosilane and silane can be deposited on the metal surface stably, so that the coating has a very low surface energy, so that the coating The quality is relatively stable and achieves a good hydrophobic effect, which makes the copper corrosion resistance and cleaning better, and the service life is longer.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the scanning electron microscope figure after the copper sheet etching of embodiment 2 of the present invention;

Fig. 2 is the scanning electron micrograph of the superhydrophobic coating that the embodiment of the present invention 2 prepares;

Fig. 3 is the scanning electron microscope figure after the copper sheet etching of comparative example 1 of the present invention;

Fig. 4 is the scanning electron micrograph of the superhydrophobic coating that comparative example 1 of the present invention prepares;

Fig. 5 is the scanning electron microscope figure after the copper sheet etching of comparative example 2 of the present invention;

Fig. 6 is the scanning electron micrograph of the superhydrophobic coating that comparative example 2 of the present invention prepares;

Fig. 7 is the scanning electron microscope figure after the copper sheet etching of comparative example 3 of the present invention;

Fig. 8 is the scanning electron micrograph of the superhydrophobic coating that comparative example 3 of the present invention prepares;

Fig. 9 is a contact angle diagram of the superhydrophobic coating prepared in Example 2 of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other implementations obtained by persons of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

Example 1

A kind of preparation method of superhydrophobic coating of the present embodiment, described method comprises the steps:

(1) Substrate pretreatment: select a circular copper sheet with a diameter of 1 cm and a thickness of 0.2 mm, and polish and derust the surface of the copper sheet sequentially through 400 mesh, 600 mesh, 1000 mesh, 1500 mesh, and 2000 mesh sandpaper, and then Use acetone, ethanol, and deionized water to ultrasonically clean surface oil stains and other impurities, and dry them for later use;

(2) Copper sheet etching: first copper sheet is immersed in the mixed solution of sodium chloride and hydrochloric acid 4h, and the mixed solution of sodium chloride and hydrochloric acid is the sodium chloride aqueous solution that concentration is 1mol/L and mass fraction is 10% hydrochloric acid The solutions are mixed in equal volumes, cleaned with deionized water, dried, and then immersed in the mixed solution of hydrogen peroxide and hydrochloric acid for 4 hours. The mixed solution of hydrogen peroxide and hydrochloric acid is 14% hydrogen peroxide and 10% hydrogen peroxide. Hydrochloric acid solution is mixed in equal volumes, washed with deionized water, dried, and then immersed in the mixed solution of ferric chloride and hydrochloric acid for 4 hours. The mixed solution of ferric chloride and hydrochloric acid is a mass fraction of 30% ferric chloride aqueous solution and The hydrochloric acid solution with a mass fraction of 5% is mixed in equal volumes, washed three times with deionized water, and dried for later use. During the etching process, the etching solution and the copper piece are filled into a three-neck round bottom flask and fixed in the In the iron stand, place the stirring rod vertically above the copper sheet, and adjust the stirring speed at 235r/min;

(3) Put tridecafluorozinc-based triethoxysilane and octadecyltrimethoxysilane in a volume ratio of 1:1, the total volume is 0.2ml, and the etched copper sheet is put into the reaction kettle for the first First heating, the heating temperature is 130°C, the heating time is 4h, cooled to room temperature, put into the oven for the second heating, the heating temperature is 165°C, the heating time is 2.2h, and a superhydrophobic coating is formed on the surface of the copper sheet. Floor.

Example 2

A kind of preparation method of superhydrophobic coating of the present embodiment, described method comprises the steps:

(1) Substrate pretreatment: select a circular copper sheet with a diameter of 1 cm and a thickness of 0.2 mm, and polish and derust the surface of the copper sheet sequentially through 400 mesh, 600 mesh, 1000 mesh, 1500 mesh, and 2000 mesh sandpaper, and then Use acetone, ethanol, and deionized water to ultrasonically clean surface oil stains and other impurities, and dry them for later use;

(2) Copper sheet etching: earlier copper sheet is immersed in the mixed solution of sodium chloride and hydrochloric acid 6h, and the mixed solution of sodium chloride and hydrochloric acid is the sodium chloride aqueous solution that concentration is 1.5mol/L and mass fraction is 15% Hydrochloric acid solution is mixed in equal volumes, cleaned with deionized water, dried, and then immersed in a mixed solution of hydrogen peroxide and hydrochloric acid for 7 hours. The mixed solution of hydrogen peroxide and hydrochloric acid is 15% hydrogen peroxide and 15% hydrogen peroxide. The hydrochloric acid solution is mixed in equal volumes, washed with deionized water, dried, and then immersed in the mixed solution of ferric chloride and hydrochloric acid for 5 hours. The mixed solution of ferric chloride and hydrochloric acid is a 35% ferric chloride aqueous solution It is mixed with equal volumes of hydrochloric acid solution with a mass fraction of 7.5%, washed three times with deionized water, and dried for later use. During the etching process, horizontal stirring is selected, and the etching solution and copper sheet are put into a beaker, and the ultrasonic machine An iron stand that can be rotated left and right is fixed next to it, the stirring rod is placed horizontally, and the stirring rate is 180r/min;

(3) Put tridecafluorozinc-triethoxysilane and octadecyltrimethoxysilane at a volume ratio of 1:1.4, the total volume is 0.3ml, and the etched copper sheet is put into the reaction kettle for the first First heating, the heating temperature is 135°C, the heating time is 3.5h, cooled to room temperature, put into the oven for the second heating, the heating temperature is 167°C, the heating time is 2h, and a superhydrophobic coating is formed on the surface of the copper sheet. Floor.

Example 3

A kind of preparation method of superhydrophobic coating of the present embodiment, described method comprises the steps:

(1) Substrate pretreatment: select a circular copper sheet with a diameter of 1 cm and a thickness of 0.2 mm, and polish and derust the surface of the copper sheet sequentially through 400 mesh, 600 mesh, 1000 mesh, 1500 mesh, and 2000 mesh sandpaper, and then Use acetone, ethanol, and deionized water to ultrasonically clean surface oil stains and other impurities, and dry them for later use;

(2) Copper sheet etching: first copper sheet is immersed in the mixed solution of sodium chloride and hydrochloric acid 8h, and the mixed solution of sodium chloride and hydrochloric acid is the sodium chloride aqueous solution that concentration is 2mol/L and mass fraction is 20% hydrochloric acid The solution is mixed in equal volumes, dried, and then immersed in the mixed solution of hydrogen peroxide and hydrochloric acid for 10 hours. The mixed solution of hydrogen peroxide and hydrochloric acid is made by mixing equal volumes of hydrogen peroxide with a mass fraction of 16% and a hydrochloric acid solution with a mass fraction of 20%. , wash with deionized water, dry, the mixed solution of ferric chloride and hydrochloric acid is that the mass fraction is 40% ferric chloride aqueous solution and the mass fraction is that the hydrochloric acid solution of 10% mixes equal volumes, washes three times with deionized water, Dry it for later use, stir vertically during the etching process, put the etching solution and copper sheet into a three-neck round bottom flask, fix it in the iron stand, place the stirring rod vertically above the copper sheet, and adjust the stirring speed at 250r/min;

(3) Put tridecafluorozinc-triethoxysilane and octadecyltrimethoxysilane in a volume ratio of 1:2, the total volume is 0.4ml, and the etched copper sheet is put into the reaction kettle for the first First heating, the heating temperature is 140°C, the heating time is 3h, cooled to room temperature, put into the oven for the second heating, the heating temperature is 170°C, the heating time is 1.8h, and a superhydrophobic coating is formed on the surface of the copper sheet. Floor.

The scanning electron micrograph of the copper sheet etching in embodiment 2 is as shown in Figure 1, and the scanning electron micrograph of the superhydrophobic coating prepared in embodiment 2 is as shown in Figure 2, and the inventor has also done embodiment 1 and 3 The scanning electron micrographs are basically consistent with those in Example 2, and are not listed one by one due to limited space.

Comparative example 1

The preparation method of the superhydrophobic coating of this comparative example is the same as that of Example 2, and the difference is that the etching in step (2) only adopts the immersion treatment in the mixed solution of sodium chloride and hydrochloric acid, wherein, after the copper sheet is etched The scanning electron micrograph of the superhydrophobic coating is shown in Figure 3, and the scanning electron micrograph of the superhydrophobic coating prepared in this comparative example is shown in Figure 4.

Comparative example 2

The preparation method of the superhydrophobic coating of this comparative example is the same as that of Example 2, the difference is that the etching in step (2) only adopts the immersion treatment in the mixed solution of hydrogen peroxide and hydrochloric acid, wherein the scanning of the copper sheet after etching The electron micrograph is shown in Figure 5, and the scanning electron micrograph of the superhydrophobic coating prepared in this comparative example is shown in Figure 6.

Comparative example 3

The preparation method of the superhydrophobic coating of this comparative example is the same as Example 2, and the difference is that the etching in step (2) only adopts the immersion treatment in the mixed solution of ferric chloride and hydrochloric acid, wherein, after copper sheet etching The scanning electron micrograph of the superhydrophobic coating prepared in this comparative example is shown in Figure 7, and the scanning electron micrograph of the superhydrophobic coating prepared in this comparative example is shown in Figure 8.

The test method of hydrophobic property among the present invention: measure water droplet contact angle on film layer surface with contact angle tester, contact angle value obtains after averaging by 5 random position measurements, and static contact angle adopts lying drop method (sessile drop) to measure , when measuring a superhydrophobic surface (that is, a surface with a static contact angle greater than 150°), a 5 μL water droplet is uniformly used for measurement.

Test example 1

According to the above-mentioned hydrophobic performance test method, the contact angle of the copper sheet with the superhydrophobic coating prepared in Examples 1-3 and Comparative Examples 1-3 were respectively tested, and the results are shown in Table 1.

Table 1

group Contact angle (°) Example 1 165.12 Example 2 166.47 Example 3 164.56 Comparative example 1 135.94 Comparative example 2 144.87 Comparative example 3 146.49

As can be seen from Table 1, the contact angle of the superhydrophobic coating prepared by the method of the present invention is large, that is, the hydrophobicity is good, and the contact angle of Comparative Examples 1-3 is obviously reduced. Etching by the method of the present invention can speed up the etching rate and reduce the amount of side etching and the edge, and the micro-nano topography formed on the surface of the copper sheet is more complicated, which increases the hydrophobicity of the super-hydrophobic coating. The super-hydrophobic coating prepared in Example 2 The contact angles of the hydrophobic coatings are shown in Fig. 9.

Test example 2

The copper sheet with superhydrophobic coating that embodiment 1-3 and comparative example 1-3 prepare is placed in the sodium chloride aqueous solution of 5% and corroded, measure the size of the contact angle of different corrosion times, the results are shown in Table 2.

Table 2

It can be seen from Table 2 that the superhydrophobic coating prepared by the present invention has better corrosion resistance compared with Comparative Examples 1-3, and it still shows better hydrophobicity after soaking in sodium chloride for 18 days.

Test example 3

The copper sheets with super-hydrophobic coatings prepared in Examples 1-3 and Comparative Examples 1-3 were respectively bent for different times, and the contact angle of each coating was measured. The results are shown in Table 3.

table 3

As can be seen from Table 3, the superhydrophobic coating prepared by the present invention still has a higher contact angle after being bent 30 times, and the contact angle reduction is not obvious, indicating that the bending resistance of the superhydrophobic coating prepared by the present invention is relatively high. it is good.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. a preparation method of superhydrophobic coating, is characterized in that, described method comprises the steps: (1) Substrate pretreatment: select copper sheets for derusting, ultrasonically clean them with acetone, ethanol, and deionized water in turn, and dry them for later use; (2) copper sheet etching: immerse the pretreated copper sheet in the etching solution and react for 12-24h, wash three times with deionized water, and dry for subsequent use; (3) Put the fluorosilane, silane and etched copper sheet into the reaction kettle for the first heating, cool to room temperature, put it into the oven for the second heating, and form a superhydrophobic coating on the surface of the copper sheet. 2. the preparation method of superhydrophobic coating according to claim 1 is characterized in that, the copper sheet in step (1) is polished and derusted through 400 order, 600 order, 1000 order, 1500 order, 2000 order sandpaper successively . 3. the preparation method of superhydrophobic coating according to claim 1, it is characterized in that, the etching described in step (2) is that earlier copper sheet is immersed in the mixed solution of sodium chloride and hydrochloric acid 4-8h , cleaned with deionized water, dried, then immersed in a mixed solution of hydrogen peroxide and hydrochloric acid for 4-10 hours, washed with deionized water, dried, and then immersed in a mixed solution of ferric chloride and hydrochloric acid for 4-6 hours. 4. the preparation method of superhydrophobic coating according to claim 3 is characterized in that, the mixed solution of sodium chloride and hydrochloric acid is that concentration is the sodium chloride aqueous solution of 1-2mol/L and massfraction is 10-20% Mix equal volumes of hydrochloric acid solution. 5. the preparation method of superhydrophobic coating according to claim 3 is characterized in that, the mixed solution of hydrogen peroxide and hydrochloric acid is that the hydrogen peroxide of 14-16% and mass fraction are equal volumes of hydrochloric acid solution of 10-20% mixed. 6. the preparation method of superhydrophobic coating according to claim 3 is characterized in that, the mixed solution of ferric chloride and hydrochloric acid is that massfraction is that 30-40% ferric chloride aqueous solution and massfraction are 5-10% Mix equal volumes of hydrochloric acid solution. 7. The preparation method of superhydrophobic coating according to claim 1, is characterized in that, in step (3), the volume ratio of fluorosilane and silane is 1:1-2. 8. according to the preparation method of claim 1 or 7 described superhydrophobic coatings, it is characterized in that, described fluorosilane is tridecafluorozinc triethoxysilane, and described silane is octadecyl trimethyl Oxysilane. 9. The preparation method of the superhydrophobic coating according to claim 1, characterized in that, the temperature of the first heating in step (3) is 130-140°C, and the heating time is 3-4h. 10. The preparation method of the superhydrophobic coating according to claim 1, characterized in that, the temperature of the second heating in step (3) is 165-170°C, and the heating time is 1.8-2.2h.