CN110625208A - Wavy structure superhydrophobic surface for anti-icing and preparation method thereof - Google Patents

Abstract

The invention discloses a wave-structured superhydrophobic surface for anti-icing and a preparation method thereof, belonging to the technical field of surface treatment of metal substrates. Including: selecting the base material, processing the wave structure on the base material by wire cutting finishing technology; pre-treating the prepared wave structure, using wet etching to prepare the hydrophobic micron flower structure on the surface of the wave structure; making the hydrophobic micron flower structure Modified with low surface energy substances to produce a super-hydrophobic surface with a wavy structure. The wave structure superhydrophobic surface is an asymmetric surface, and the droplet impacts on the wave structure to produce asymmetric bounce. Compared with the symmetrical bounce generated by the droplet impact on the equivalent superhydrophobic surface, the solid-liquid contact time of the asymmetric bounce 40% shorter. The superhydrophobic surface of the wave structure of the present invention improves the contact characteristics between the metal substrate and water droplets, and the micron flower structure modified by low surface energy substances can also reduce the viscosity of water droplets sliding over the surface, and reduce the degree of condensation of water droplets on the surface of the substrate , to achieve the purpose of anti-icing with high efficiency, cleanliness and low cost.

Description

Wavy structure superhydrophobic surface for anti-icing and preparation method thereof

technical field

The invention belongs to the technical field of surface treatment of metal substrates, and relates to a wave-structure super-hydrophobic surface for anti-icing and a preparation method thereof.

Background technique

In a low temperature environment, the surface of power transmission and communication lines, aviation, navigation or high-speed rail transportation equipment often freezes due to condensation of water vapor or the impact and accumulation of supercooled water droplets, which will bring great harm to the use of equipment and personal safety. For example, for high-voltage wires for long-distance power transmission, icing increases the load on the iron towers supporting the high-voltage wires. Severe icing made the tower unable to support the wires and collapsed. However, if the insulator strings on the iron tower are covered with ice, they can only switch on the power transmission line to stop the power transmission, thus causing a large-scale power interruption; the probes of the speed measuring and pressure measuring sensors on the aircraft and ships will be frozen, which will cause the instrument indication to be distorted. The icing of the body and the hull will increase its own weight and increase the navigation resistance. Therefore, for a long time, the problem of anti-icing on the surface of equipment such as power transmission and communication lines, aviation, navigation or high-speed rail transportation has been highly valued.

Engineering mainly uses mechanical or heating technology to de-ice and melt ice, but these methods are often accompanied by complex structural design and a lot of extra energy consumption. In recent years, superhydrophobic technology has received extensive attention, and has shown good application prospects in the fields of self-cleaning surfaces, microfluidic control, and oil-water separation. A large number of studies have also shown that superhydrophobic surfaces have excellent anti-icing properties, that is, delay, reduce or even completely prevent the accumulation of frost on solid surfaces. These active anti-icing technologies have received more and more attention by constructing hydrophobic functional coatings on the surface of materials, or by hydrophobically treating the original material surface to make it anti-icing.

At present, most of the superhydrophobic surfaces used for anti-icing are based on the hydrophobic treatment of planes or the construction of hydrophobic functional coatings. Under the same hydrophobic treatment conditions, superhydrophobic surfaces with wavy structures have better performance than superhydrophobic surfaces. Anti-icing performance, and the wave structure can reduce and avoid the adhesion and accumulation of water droplets on the surface, or it is easier to slide off the surface by gravity, wind or other external forces before the water droplets freeze, thereby further reducing the ice on its surface. Opportunities for surface formation.

Contents of the invention

The present invention aims at the limitation that most existing super-hydrophobic surfaces are subjected to hydrophobic treatment based on planes, and provides a method for preparing a wave-structured super-hydrophobic surface for anti-icing. The superhydrophobic surface of the wave structure is an asymmetric surface. When the droplet hits the wave structure, it will bounce asymmetrically, and there will be obvious expansion and contraction along two vertical directions, which is symmetrical with the impact of the droplet on the equivalent superhydrophobic horizontal plane. The solid-liquid contact time of this asymmetric bounce is shortened by 40% compared with the normal bounce. Therefore, the superhydrophobic surface with a wavy structure has superhydrophobic properties and can also reduce solid-liquid contact time and heat exchange to achieve efficient, clean, and low-cost anti-icing.

The present invention is achieved through the following technical solutions:

A wavy structure superhydrophobic surface for anti-icing, including a wavy structure substrate, a hydrophobic microflower structure and a low surface energy material modification layer, wherein the hydrophobic microflower structure is evenly distributed on the upper surface of the wave structure substrate, and the low surface energy substance The modification layer is attached to the upper surface of the hydrophobic microflower structure.

The wave structure is a semi-cylindrical structure with alternating concavities and convexities, with a diameter of 4-20 mm. The hydrophobic microflowers have a spherical structure, are uniformly distributed on the upper surface of the wave structure, and have a diameter of 5-20 μm. The material composition of the low surface energy material modification layer is trichloro-(1H,1H,2H,2H)-perfluorooctylsilane.

A preparation method for an anti-icing wavy structure super-hydrophobic surface, comprising the following steps:

The first step is to select industrial pure copper as the base material, and use the wire cutting finishing technology to process the wave structure on the base material;

The purity of the selected base material is greater than 99%. The wire-cut finishing technology refers to processing the wave structure on the base material by using the wire-cut finishing method, and the dimensional processing accuracy is less than 0.015mm.

In the second step, the prepared wave structure is pretreated, and a hydrophobic micro flower structure is prepared on the surface of the wave structure by wet etching;

The pretreatment of the prepared wave structure includes the following operations: first corrode cleaning with 1mol/L dilute hydrochloric acid solution to remove the surface oxidation/hydroxide film, and then ultrasonically clean it with acetone, absolute ethanol and deionized water for 8 ~12min, then dry with nitrogen.

The preparation of the hydrophobic micron flower structure on the surface of the wave structure by wet etching includes the following operations: preparing a mixed solution of 2.5 mol/L NaOH and 0.1 mol/L (NH ₄ ) ₂ S ₂ O ₈ , pretreated After soaking and reacting for 60-90 minutes at room temperature, take out the wavy structure, wash it with deionized water, and dry it with nitrogen.

In the third step, the hydrophobic microflower structure is modified with low surface energy substances to obtain a superhydrophobic surface with a wavy structure.

The modification of the hydrophobic microflower structure with low surface energy substances refers to immersing the surface of the hydrophobic microflower structure with 1 mmol/L fluorosilane alcohol solution for 40-60 minutes, and finally heating and drying at 80-150° C. for more than 1 hour.

The fluorosilane is trichloro-(1H,1H,2H,2H)-perfluorooctylsilane.

The beneficial effects of the present invention are:

(1) The superhydrophobic surface of the wave structure is an asymmetric surface. When the droplet hits the wave structure, it will produce an asymmetric bounce. Compared with the symmetrical bounce generated by the droplet hitting the equivalent superhydrophobic surface, this The solid-liquid contact time for asymmetric bounces has been reduced by 40%.

(2) The present invention is based on wire-cut finishing technology and surface modification technology, and is realized by constructing a super-hydrophobic surface with a wave structure on an industrial pure copper substrate at room temperature. The preparation method is simple, easy to operate, high in efficiency and low in cost, and has no special requirements on the shape and material of the metal substrate.

(3) Compared with the existing super-hydrophobic surface, the super-hydrophobic surface with wave structure improves the contact characteristics between water droplets and the surface. With super-hydrophobic properties, it can also reduce the solid-liquid contact time and heat exchange. The wave structure can be further improved. Reduce and avoid the attachment and accumulation of water droplets on the surface, and it is easier to slide off the surface with the help of gravity, wind or other external forces before the water droplets freeze, so the super-hydrophobic surface with wave structure has better anti-icing performance.

Description of drawings

Fig. 1 is a schematic diagram and an SEM image of a superhydrophobic surface with a wavy structure prepared in Example 1 of the present invention.

Specific implementation form

The technical solution of the present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings.

Example 1

A method for preparing an anti-icing wave-structured superhydrophobic surface of the present embodiment comprises the following specific steps:

The first step is to select the base material, and process the wave structure on the base material by wire-cut finishing technology;

In this example, the selected base material is industrial pure copper with a purity greater than 99%. The wire cutting machine used for wire cutting finishing is DK7732E CNC fast-feeding wire cutting machine, and the dimensional processing accuracy is less than 0.015mm. The processed wave structure is a concave-convex semi-cylindrical structure with a diameter of 8 mm. The structure is shown in Figure 1.

The second step is to pretreat the wave structure obtained in the first step, and prepare a hydrophobic micron flower structure on the surface of the wave structure by wet etching;

First use 1mol/L dilute hydrochloric acid solution to etch and clean to remove the surface oxidation/hydroxide film, then use acetone, absolute ethanol and deionized water to ultrasonically clean for 8 minutes, and then blow dry with nitrogen. Then prepare a mixed solution of 2.5mol/L NaOH and 0.1mol/L (NH ₄ ) ₂ S ₂ O ₈ , soak and react the pretreated wave structure at room temperature for 60 minutes, take it out and wash it with deionized water, and use nitrogen gas to clean it. blow dry. The prepared hydrophobic microflower structure is evenly distributed on the upper surface of the wavy structure, and the monomer structure is a spherical structure with an average diameter of 5 μm. The SEM image is shown in FIG. 1 .

In the third step, the hydrophobic microflower structure is modified with a low surface energy substance to obtain a superhydrophobic surface with a wavy structure.

Soak the surface of the hydrophobic microflower structure with 1mmol/L fluorosilane alcohol solution for 60min, and finally heat and dry at 150°C for 1h. The fluorosilane used is trichloro-(1H,1H,2H,2H)-perfluorooctylsilane, and the low surface energy material modification layer is attached to the upper surface of the hydrophobic microflower structure, and its material composition is trichloro-(1H, 1H,2H,2H)-Perfluorooctylsilane. The contact angle is 163.4°±2.6°.

Example 2

A method for preparing an anti-icing wave-structured superhydrophobic surface of the present embodiment comprises the following specific steps:

The first step is to select the base material, and process the wave structure on the base material by wire cutting finishing technology;

In this example, the selected base material is industrial pure copper with a purity greater than 99%. The wire cutting machine used for wire cutting finishing is DK7732E CNC fast-feeding wire cutting machine, and the dimensional processing accuracy is less than 0.015mm. The processed wave structure is a concave-convex semi-cylindrical structure with a diameter of 15 mm.

The second step is to pretreat the wave structure obtained in the first step, and prepare a hydrophobic micron flower structure on the surface of the wave structure by wet etching;

First use 1mol/L dilute hydrochloric acid solution to etch and clean to remove the surface oxidation/hydroxide film, then use acetone, absolute ethanol and deionized water to ultrasonically clean for 10 minutes, and then blow dry with nitrogen. Then prepare a mixed solution of 2.5mol/L NaOH and 0.1mol/L (NH ₄ ) ₂ S ₂ O ₈ , soak and react the pretreated wave structure at room temperature for 90 minutes, take it out and wash it with deionized water, and use nitrogen gas to clean it. blow dry. The prepared hydrophobic microflower structure is evenly distributed on the upper surface of the wavy structure, and the monomer structure is a spherical structure with an average diameter of 13 μm.

In the third step, the hydrophobic microflower structure is modified with a low surface energy substance to obtain a superhydrophobic surface with a wavy structure.

Soak the surface of the hydrophobic microflower structure with 1mmol/L fluorosilane alcohol solution for 50min, and finally heat and dry at 80°C for 5h. The fluorosilane used is trichloro-(1H,1H,2H,2H)-perfluorooctylsilane, and the low surface energy material modification layer is attached to the upper surface of the hydrophobic microflower structure, and its material composition is trichloro-(1H, 1H,2H,2H)-Perfluorooctylsilane. The contact angle was 162.8°±2.3°.

The above-mentioned embodiment only expresses the implementation mode of the present invention, but can not therefore be interpreted as the limitation of the scope of the patent of the present invention, it should be pointed out that, for those skilled in the art, under the premise of not departing from the concept of the present invention, Several modifications and improvements can also be made, all of which belong to the protection scope of the present invention.

Claims (8)

1. The anti-icing super-hydrophobic surface with the wave structure is characterized by comprising a wave structure substrate, hydrophobic micro-flower rice structures and a low-surface-energy substance modification layer, wherein the hydrophobic micro-flower rice structures are uniformly distributed on the upper surface of the wave structure substrate, and the low-surface-energy substance modification layer is attached to the upper surface of the hydrophobic micro-flower rice structures;

the wave structure is a concave-convex alternated semi-cylinder structure, and the diameter of the wave structure is 4-20 mm; the hydrophobic micro-flowers are spherical structures, and the diameter size of the hydrophobic micro-flowers is 5-20 mu m.

2. The super-hydrophobic surface with a wavy structure for resisting ice according to claim 1, wherein the substance component of the low surface energy substance modification layer is trichloro- (1H,1H,2H,2H) -perfluorooctylsilane.

3. A method for preparing the superhydrophobic surface of the wavy structure for resisting ice according to claim 1 or 2, comprising the steps of:

firstly, selecting industrial pure copper as a base material, and processing a wavy structure on the base material by adopting a wire-electrode cutting finish machining technology;

secondly, preparing a hydrophobic micro-flower structure on the surface of the wave structure

2.1) pretreating the prepared wave structure: firstly, using dilute hydrochloric acid solution to corrode and clean, removing surface oxidation/hydroxide film, then using acetone, absolute ethyl alcohol and deionized water to ultrasonically clean, and using nitrogen to blow and dry

2.2) preparing a hydrophobic micro-flower structure on the surface of the wave structure by wet etching: 2.5mol/L NaOH and 0.1mol/L (NH) are prepared₄)₂S₂O₈Mixing the solution, soaking the pretreated wavy structure at room temperature for reaction for 60-90 min, taking out, washing with deionized water, and drying with nitrogen;

and thirdly, soaking the surface of the hydrophobic micro-flower structure with 1mmol/L of fluorosilane alcohol solution for 40-60 min, heating and drying, and modifying the hydrophobic micro-flower structure with a low-surface-energy substance to obtain the super-hydrophobic surface with a wave structure.

4. The method for preparing the superhydrophobic surface with the wavy structure for resisting ice according to claim 3, wherein the purity of the substrate in the first step is more than 99%.

5. The method for preparing the anti-icing waved structure superhydrophobic surface according to claim 3, wherein the size processing precision of the wire-electrode cutting finishing technology in the first step is less than 0.015 mm.

6. The method for preparing the anti-icing wave structure superhydrophobic surface according to the claim 3, wherein the concentration of the dilute hydrochloric acid in the second step 2.1) is 1 mol/L; the ultrasonic cleaning time is 8-12 min.

7. The method for preparing the anti-icing wave-structure superhydrophobic surface according to claim 3, wherein the temperature of the heating and drying in the third step is 80-150 ℃ and the time is more than 1 h.

8. The method for preparing the anti-icing wave-structured superhydrophobic surface according to claim 3, wherein the fluorosilane of the third step is trichloro- (1H,1H,2H,2H) -perfluorooctylsilane.