CN106423789B - A kind of durability anti-ice super-hydrophobic coat and preparation method thereof - Google Patents

Abstract

The invention discloses a durable ice-resistant super-hydrophobic coating and a preparation method thereof. It consists of a metal groove structure at the bottom, a middle polymer layer, and an upper nanoparticle-polymer composite layer. It is based on smooth steel. After laser etching the groove structure, it is coated with a layer of pure polymer coating, and then sprayed with high Molecular-nano composite coatings are obtained by first using a laser to etch a regular groove structure on the smooth steel surface; then after the steel is treated with _O2 plasma, the molten ultra-high molecular polyethylene is sprayed at a high temperature and dried to form a film; Finally, the mixture of ultra-high molecular polyethylene and hydrophobic nano-Al ₂ O ₃ is sprayed, and the desired coating is obtained after drying. The superhydrophobic coating of the present invention has better mechanical stability and environmental durability, and has excellent anti-icing performance.

Description

A durable anti-icing superhydrophobic coating and preparation method thereof

technical field

The invention belongs to the field of materials, and relates to a durable ice-resistant superhydrophobic coating and a preparation method thereof.

Background technique

The surface of lotus leaves in nature is extremely non-wetting to water, which is called superhydrophobic phenomenon. It has been found through research that the surface of the lotus leaf has a micron and nanometer level structure, and the surface is covered with a layer of wax with low surface energy, so it has super-hydrophobic properties. Therefore, biomimetic superhydrophobic interfaces can be obtained by preparing such hierarchical structures in various ways and subsequent low surface energy modification.

Due to its excellent water resistance and water repellency, superhydrophobic interfaces have great application prospects in the fields of underwater drag reduction, self-cleaning surfaces, metal protection, and anti-icing and anti-icing fields. The main problem with current superhydrophobic coatings is the fragile surface structure. Although there are various ways to prepare super-hydrophobic interfaces, the surface structure can be destroyed with very light external scratches, thus losing super-hydrophobicity, which is a bottleneck problem restricting its large-scale practical industrialization.

Peng et al prepared a wear-resistant superhydrophobic coating on the surface of pure aluminum (Chemically Stable and Mechanically Durable Superamphiphobic Aluminum Surface with a Micro/Nanoscale Binary Structure, ACS Appl. Mater. Interfaces , 2014, 6 (17), pp 15188–15197 ). They polished and cleaned pure aluminum, put it into 2.5 M HCl solution for etching, then dried the coating and put it in a high-pressure reactor at 120 °C for hydrothermal reaction to obtain interface micro-nano structure; Finally, the coating was immersed in perfluorosilane for surface modification to obtain a superhydrophobic coating. This method has strict restrictions on the type of substrate and can only be carried out on the surface of aluminum alloy. At the same time, due to the need for hydrothermal reaction to micro-nano surface, there are strict regulations on the sample size and size. CPWong's research group successfully prepared superhydrophobic coatings with certain mechanical stability on silicon wafers (Mechanically robust superhydrophobicity on hierarchically structured Si surfaces, Nanotechnology 21 (2010) 155705). They used H ₂ O ₂ and HF acid co-etching to prepare nanostructures on Si wafers, and carried out friction tests. Although it has a certain degree of mechanical stability, it loses its superhydrophobicity when it is rubbed on a relatively smooth rag, and the maximum friction is 25 cm, so the stability still needs to be improved.

Contents of the invention

The object of the present invention is to provide a durable ice-resistant super-hydrophobic coating and its preparation method, which consists of a metal groove structure at the bottom of the interface, a middle polymer layer, and an upper nanoparticle-polymer composite layer. The durable anti-icing superhydrophobic coating is processed by using a laser to process the polished and polished steel to obtain a groove structure at the bottom; then the ultra-high molecular polyethylene solution is sprayed on the surface of the groove structure and dried to obtain a middle polymer layer ; Finally, the mixture of ultrahigh molecular polyethylene and modified hydrophobic Al ₂ O ₃ nanoparticles was sprayed on the substrate to obtain the upper nanoparticle-polymer composite layer. The coating still has superhydrophobicity and excellent anti-icing effect after external abrasion.

The technical solution that realizes the object of the present invention is:

A durable ice-resistant super-hydrophobic coating, which consists of a metal groove structure at the bottom, a middle polymer layer, and an upper nanoparticle-polymer composite layer.

Further, the metal groove structure is a steel groove structure after laser grinding and polishing; the groove concave structure has a depth of 200-300 μm and a width of 50-150 μm; the convex structure has a width of 100-200 μm. μm.

The polymer layer is obtained by spraying ultra-high molecular polyethylene solution onto the surface of the groove structure and then drying; the molecular weight of the ultra-high molecular polyethylene is 5,000,000, and the solvent used for spraying is decahydronaphthalene.

The particle size of the nano Al ₂ O ₃ particles is 50-100 nm, and its hydrophobic treatment is to immerse the nanoparticles in an ethanol solution of 0.05-0.08 mol/L heptadecafluorodecyltriethoxysilane, and the immersion temperature is The temperature is 50~60 °C, and the soaking time is 3~4 h.

The preparation method of above-mentioned durability anti-icing superhydrophobic coating, comprises the following steps:

1) Use laser to process the polished and polished steel to obtain the bottom groove structure;

2) Spray the ultra-high molecular polyethylene solution onto the surface of the groove structure and then dry it to obtain the middle polymer layer;

3) Spray the mixture of ultrahigh molecular polyethylene and modified hydrophobic Al ₂ O ₃ nanoparticles on the substrate to obtain the upper nanoparticle-polymer composite layer.

The concentration of the ultrahigh molecular polyethylene solution is 2 ~ 5 g/L, and the spraying temperature is 150 ° C.

The concentration of the hydrophobic nano Al ₂ O ₃ particles is 20-40 g/L, the concentration of ultra-high molecular weight polyethylene is 6-10 g/L, and the spraying temperature is 150°C.

Compared with the prior art, the significant advantages of the present invention are: 1) The excellent mechanical stability of ultra-high molecular polyethylene provides mechanical support for the nanoparticles, and the coating has good wear resistance; There are no requirements for the size and shape of the invention, and a wide range of preparation can be realized; 3) The invention has excellent anti-icing performance.

Description of drawings

Fig. 1 is the water droplet contact angle, rolling angle of durable anti-icing superhydrophobic coating of embodiment 1.

Fig. 2 is the water drop contact angle and rolling angle of the durable anti-icing superhydrophobic coating of embodiment 1 after abrasion.

Fig. 3 is a comparison chart of the icing conditions of the coating in Example 1.

Detailed ways

Below in conjunction with embodiment the present invention is described in further detail.

Example 1

(1) After the steel is polished, the groove structure is obtained by laser treatment. The depth of the concave structure is 250 μm, and the width is 100 μm; the width of the convex structure is 120 μm;

(2) After cleaning the sample obtained in step (1), spray a decahydronaphthalene solution with a concentration of 4 g/L ultra-high molecular polyethylene on the surface of the groove structure and dry it to obtain the middle polymer layer.

(3) Soak Al ₂ O ₃ particles with a particle size of 70 nm in 0.06 mol/L ethanol solution of heptadecafluorodecyltriethoxysilane at 55 °C for 3.5 h .

(4) Add the hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular weight polyethylene obtained in step (3) into decahydronaphthalene, keeping the concentration of Al ₂ O ₃ at 35 g/L, and the concentration of ultra-high molecular weight polyethylene at 8 g /L. The above mixture is heated to 150 °C, sprayed on the coating described in step (2) and dried to obtain the upper nanoparticle-polymer composite layer.

On the prepared coating, the static contact angle of water droplets reaches 160°, and the rolling angle is 2°, as shown in Figure 1. After grinding for 2 m on 5kPa, 200# sandpaper, the contact angle is 155° and the rolling angle is 5°, as shown in Figure 2. After the friction test, the coating was placed in a condensation and icing test environment at -20 °C and 90% humidity, and no obvious frost appeared on the surface of the coating, indicating that the coating has excellent anti-icing performance, as shown in Figure 3.

Example 2

(1) After the steel is polished, the groove structure is obtained by laser treatment. The depth of the concave structure is 200 μm, and the width is 150 μm; the width of the convex structure is 100 μm;

(2) After cleaning the sample obtained in step (1), spray a decahydronaphthalene solution with a concentration of 5 g/L ultra-high molecular polyethylene on the surface of the groove structure and dry it to obtain an intermediate polymer layer.

(3) Soak Al ₂ O ₃ particles with a particle size of 50 nm in 0.07 mol/L ethanol solution of heptadecafluorodecyltriethoxysilane at 50 °C for 4 h .

(4) Add the hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular weight polyethylene obtained in step (3) into decahydronaphthalene, keeping the concentration of Al ₂ O ₃ at 40 g/L, and the concentration of ultra-high molecular weight polyethylene at 6 g /L. The above mixture is heated to 150 °C, sprayed on the coating described in step (2) and dried to obtain the upper nanoparticle-polymer composite layer.

On the prepared coating, the static contact angle of water droplets reaches 155°, and the rolling angle is 4°. After grinding for 2 m on 5kPa, 200# sandpaper, the contact angle is 153° and the rolling angle is 8°. After the friction test, it was placed in a condensation and icing test environment at -20 °C and 90% humidity, and no obvious frost appeared on the surface of the coating, indicating that the coating has excellent anti-icing performance.

Example 3

(1) After the steel is polished, the groove structure is obtained by laser treatment. The depth of the concave structure is 300 μm, and the width is 50 μm; the width of the convex structure is 200 μm;

(2) After cleaning the sample obtained in step (1), spray a decahydronaphthalene solution with a concentration of 3 g/L ultra-high molecular polyethylene on the surface of the groove structure and dry it to obtain an intermediate polymer layer.

(3) Soak Al ₂ O ₃ particles with a particle size of 90 nm in 0.08 mol/L ethanol solution of heptadecafluorodecyltriethoxysilane at 60 °C for 3 h .

(4) Add the hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular weight polyethylene obtained in step (3) into decahydronaphthalene, keeping the concentration of Al ₂ O ₃ at 30 g/L, and the concentration of ultra-high molecular weight polyethylene at 8 g /L. The above mixture is heated to 150 °C, sprayed on the coating described in step (2) and dried to obtain the upper nanoparticle-polymer composite layer.

On the prepared coating, the static contact angle of water droplets reaches 154°, and the rolling angle is 3°. After grinding for 2 m on 5kPa, 200# sandpaper, the contact angle is 151° and the rolling angle is 4°. After the friction test, it was placed in a condensation and icing test environment at -20 °C and 90% humidity, and no obvious frost appeared on the surface of the coating, indicating that the coating has excellent anti-icing performance.

Comparative example 1

(1) After the steel is polished, the groove structure is obtained by laser treatment. The depth of the concave structure is 200 μm, and the width is 150 μm; the width of the convex structure is 100 μm;

(2) After cleaning the sample obtained in step (1), spray a decahydronaphthalene solution with a concentration of 2 g/L ultra-high molecular polyethylene on the surface of the groove structure and dry it to obtain an intermediate polymer layer.

(3) Soak the Al ₂ O ₃ particles with a particle size of 50 nm in 0.05 mol/L ethanol solution of heptadecafluorodecyltriethoxysilane, the immersion temperature is 550 °C, and the immersion time is 3.5 h .

(4) Add the hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular weight polyethylene obtained in step (3) into decahydronaphthalene, keeping the concentration of Al ₂ O ₃ at 20 g/L, and the concentration of ultra-high molecular weight polyethylene at 7 g /L. The above mixture is heated to 150 °C, sprayed on the coating described in step (2) and dried to obtain the upper nanoparticle-polymer composite layer.

On the prepared coating, the static contact angle of water droplets reaches 130°, which does not have super-hydrophobic properties. Placed in a condensation and icing test environment at -20 °C and 90% humidity, the surface of the coating has obvious frost, indicating that the coating does not have anti-icing performance.

Comparative example 2

(1) After the steel is polished, the groove structure is obtained by laser treatment. The depth of the concave structure is 300 μm, and the width is 150 μm; the width of the convex structure is 120 μm;

(2) After cleaning the sample obtained in step (1), spray a decahydronaphthalene solution with a concentration of 2 g/L ultra-high molecular polyethylene on the surface of the groove structure and dry it to obtain an intermediate polymer layer.

(3) Soak Al ₂ O ₃ particles with a particle size of 100 nm in 0.06 mol/L ethanol solution of heptadecafluorodecyltriethoxysilane at 55 °C for 3.5 h .

(4) Add the hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular weight polyethylene obtained in step (3) into decahydronaphthalene, keeping the concentration of Al ₂ O ₃ at 25 g/L, and the concentration of ultra-high molecular weight polyethylene at 10 g /L. The above mixture is heated to 150 °C, sprayed on the coating described in step (2) and dried to obtain the upper nanoparticle-polymer composite layer.

On the prepared coating, the static contact angle of water droplets reaches 100°, which does not have super-hydrophobic properties. , placed in a condensation and icing test environment at -20 °C and 90% humidity, the surface of the coating has obvious frost, indicating that the coating does not have anti-icing performance.

Claims (7)

1. A durable ice-resistant superhydrophobic coating, characterized in that: the coating is composed of a bottom metal groove structure, a middle polymer layer, an upper nanoparticle-polymer composite layer, and the nanoparticle-polymer composite The layer is a composite coating of hydrophobic nano-Al ₂ O ₃ particles and ultra-high molecular polyethylene; the particle size of the nano-Al ₂ O ₃ particles is greater than or equal to 50 and less than 100 nm, and the hydrophobic treatment is to immerse the nanoparticles in a surface greater than 0.05 nm. , less than or equal to 0.08 mol/L heptadecafluorodecyltriethoxysilane ethanol solution, the immersion temperature is 50~60 °C, and the immersion time is 3~4 h. 2. The durable ice-resistant superhydrophobic coating according to claim 1, characterized in that: the metal groove structure is a steel groove structure after laser grinding and polishing. 3. The durable ice-resistant superhydrophobic coating according to claim 1, characterized in that: the metal groove structure is: a concave structure with a depth of 200-300 μm and a width of 50-150 μm; structure with a width of 100–200 μm. 4. The durable ice-resistant superhydrophobic coating according to claim 1, characterized in that: the polymer layer is obtained by spraying the ultrahigh molecular polyethylene solution onto the surface of the groove structure and drying it; The molecular weight of polyethylene is 5,000,000, and the solvent used for spraying is decahydronaphthalene. 5. a preparation method of the durable anti-icing superhydrophobic coating claimed in claim 1, is characterized in that comprising the following steps: 1) Use laser to process the polished and polished steel to obtain the bottom groove structure; 2) Then spray the ultra-high molecular polyethylene solution onto the surface of the groove structure and dry to obtain the middle polymer layer; 3) Spray the mixture of ultrahigh molecular polyethylene and modified hydrophobic Al ₂ O ₃ nanoparticles on the substrate to obtain the upper nanoparticle-polymer composite layer. 6. the preparation method of durable ice-resistant superhydrophobic coating according to claim 5, is characterized in that: the concentration of described ultrahigh molecular polyethylene solution is 2～5 g/L, and spraying temperature is 150 DEG C . 7. The preparation method of the durable ice-resistant superhydrophobic coating according to claim 5, characterized in that: the concentration of the hydrophobic nano-Al ₂ O ₃ particles is 20 ~ 40 g/L, ultra-high molecular weight polyethylene The concentration is 6~10 g/L, and the spraying temperature is 150 °C.