CN110552038A - super-hydrophobic material and preparation method thereof - Google Patents

Abstract

the invention discloses a super-hydrophobic material and a preparation method thereof. The super-hydrophobic material has a lotus leaf-shaped nano structure. The lotus leaf-shaped nano structure is similar to a T-shaped structure, and can directly realize super-hydrophobicity without using organic low-surface-energy substances for modification, and the material for realizing super-hydrophobicity only by structure regulation has better stability. The material with the lotus leaf-shaped nano structure can be aluminum oxide which is used as a wear-resistant corrosion-resistant coating of a common workpiece, so that the nano aluminum oxide with the special structure prepared by the micro-arc oxidation method also has excellent stability. In addition, the preparation method of the super-hydrophobic material provided by the invention is simple and easy to operate, has lower cost and has potential application value.

Description

A kind of superhydrophobic material and preparation method thereof

technical field

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

Background technique

Due to the special wettability of the surface, superhydrophobic materials have broad application prospects in many fields of interface science, including cleaning, anti-icing, anti-fog, flow drag reduction, oil-water separation, metal anti-corrosion and other scenarios.

In recent years, there are three main strategies for the preparation of superhydrophobic materials. One is to construct micro-nano structures on the surface of hydrophobic low-surface-energy materials; the other is to construct micro-nano structures on the surface of materials and then modify them with organic low-surface-energy substances; It is to build a T-shaped micro-nano structure on the surface of the material. Among them, the first two strategies use organic low surface energy substances, which have poor stability such as temperature resistance. The third strategy only needs to construct a special T-shaped structure to achieve superhydrophobicity. In the process, no organic low-surface-energy substances are used for modification, and the material often shows better stability. In the preparation of superhydrophobic materials There are obvious advantages in many methods.

At present, laser etching or chemical etching is mainly used to precisely control the surface structure to construct T-shaped structures on the surface of materials to obtain superhydrophobicity. However, most laser etching methods or chemical etching methods have problems such as harsh experimental conditions, complicated steps, high cost, and inability to prepare in batches.

Therefore, the prior art still needs to be improved and developed.

Contents of the invention

In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a simple and low-cost method for preparing superhydrophobic materials similar to T-shaped structures for the existing problems in the preparation methods that only rely on regulating the material structure to obtain superhydrophobic materials. Lotus leaf-like nanostructured superhydrophobic materials and methods thereof.

Technical scheme of the present invention is as follows:

A super-hydrophobic material, wherein the super-hydrophobic material has a lotus leaf-like nanostructure.

Further, the superhydrophobic material is a metal oxide having a lotus leaf-like nanostructure.

Furthermore, the superhydrophobic material is aluminum oxide with a lotus leaf-like nanostructure.

A method for preparing a super-hydrophobic material, wherein the super-hydrophobic material with a lotus leaf-like nanostructure is prepared by using a micro-arc oxidation technique.

Further, steps are included:

Provide metal substrate;

The superhydrophobic material is obtained by forming a metal oxide having a lotus-leaf-like nanostructure on the metal substrate by using a micro-arc oxidation technique.

Further, steps are included:

Provide aluminum or aluminum alloy, and sequentially polish and clean the aluminum or aluminum alloy;

Put the aluminum or aluminum alloy after the above treatment into the alkaline electrolyte, connect the aluminum or aluminum alloy to the positive pole of the power supply, connect the negative pole of the power supply to the working electrode, and the working electrode is in contact with the electrolyte, and turn on the power supply for micro-arc oxidation treatment;

After the micro-arc oxidation treatment, washing and drying are carried out to obtain aluminum oxide with a lotus leaf-like nanostructure on the surface of the aluminum or aluminum alloy, that is, the superhydrophobic material is obtained.

Furthermore, the alkaline electrolyte includes: 3-20g/L phosphate, 1-5g/L alkaline hydroxide, and the solvent is water.

Still further, the phosphate is selected from one or more of sodium hexametaphosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium tripolyphosphate, trisodium phosphate and sodium pyrophosphate.

Still further, the alkaline hydroxide is selected from one or more of sodium hydroxide and potassium hydroxide.

Further, the process conditions of the micro-arc oxidation treatment include:

The selected power supply is a pulse power supply. The operating parameters of the pulse power supply are: under constant current mode, the current density is 1-40A/dm ² , the frequency is 100-2000Hz, the duty cycle is 10-15%, and the micro-arc oxidation time is 1 -10min.

Beneficial effects: the present invention provides a superhydrophobic material with a lotus-leaf-like nanostructure, the lotus-leaf-like nanostructure is similar to a T-shaped structure, and can directly realize superhydrophobicity without modification with organic low-surface-energy substances . In addition, the preparation method of the superhydrophobic material having a lotus leaf-like nanostructure is simple, easy to operate, and low in cost, and has potential application value.

Description of drawings

Fig. 1 is the front SEM figure of the lotus-leaf-shaped nano-alumina superhydrophobic material prepared in Example 1.

2 is a cross-sectional SEM image of the lotus leaf-shaped nano-alumina superhydrophobic material prepared in Example 1.

Fig. 3 is the XRD pattern of the lotus leaf-shaped nano-alumina superhydrophobic material prepared in Example 1.

Fig. 4 is the contact angle diagram of the lotus leaf-shaped nano-alumina superhydrophobic material prepared in Example 1 to water.

Detailed ways

The present invention provides a superhydrophobic material and a preparation method thereof. In order to make the purpose, technical solution and effect of the present invention clearer and more definite, the present invention will be further described in detail below. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

An embodiment of the present invention provides a superhydrophobic material, wherein the superhydrophobic material has a lotus leaf-like nanostructure.

The T-shaped structure can often directly endow the surface of the material with superhydrophobicity. The upward surface tension of water droplets at the edge of the T-shaped structure is greater than the downward gravity, making it difficult for water droplets to wet the surface. Directly realize the superhydrophobicity of the material. In this embodiment, the lotus-leaf-like nanostructure is a special structure similar to T-shaped, and the contact angle to water is 150±3°, so that the material with the lotus-leaf-like nanostructure exhibits superhydrophobicity, and no The organic low surface energy substance is used to modify, and the material shows better stability.

Further, the superhydrophobic material is a metal oxide having a lotus leaf-like nanostructure.

Furthermore, the superhydrophobic material is aluminum oxide with a lotus leaf-like nanostructure. In this example, the lotus leaf-like nanostructure, similar to the T-shaped structure, can directly achieve superhydrophobicity without modification with organic low-surface-energy substances. This kind of material that achieves superhydrophobicity only by structural regulation has better Stability: the material with the lotus leaf-like nanostructure is alumina, and alumina is used as a wear-resistant and corrosion-resistant coating for common workpieces. Therefore, the special structure nano-alumina of this embodiment also has excellent stability.

An embodiment of the present invention provides a method for preparing a superhydrophobic material, wherein a superhydrophobic material with a lotus leaf-like nanostructure is prepared by using a micro-arc oxidation technique.

The embodiment of the present invention provides a method for preparing a superhydrophobic material, which includes the steps of:

Provide metal substrate;

The superhydrophobic material is obtained by forming a metal oxide having a lotus-leaf-like nanostructure on the metal substrate by using a micro-arc oxidation technique.

The embodiment of the present invention provides a method for preparing a superhydrophobic material, which includes the steps of:

S10. Provide aluminum or aluminum alloy, and sequentially perform polishing and cleaning treatment on the aluminum or aluminum alloy;

S20. Put the aluminum or aluminum alloy after the above treatment into the alkaline electrolyte, connect the aluminum or aluminum alloy to the positive pole of the power supply, connect the negative pole of the power supply to the working electrode, and the working electrode is in contact with the electrolyte, and turn on the power supply for micro-arc oxidation treatment;

S30. After the micro-arc oxidation treatment, washing and drying are performed to obtain aluminum oxide having a lotus leaf-like nanostructure on the surface of the aluminum or aluminum alloy, that is, the superhydrophobic material is obtained.

In this example, alumina with a lotus leaf-like nanostructure is synthesized in an alkaline electrolyte system by micro-arc oxidation on aluminum or aluminum alloy. This method is synthesized in one step, with simple experimental conditions and low cost; the obtained nanostructure It is a lotus leaf-like nanostructure, similar to a T-shaped structure, and can directly achieve superhydrophobicity without modification with organic low-surface-energy substances. This kind of material that achieves superhydrophobicity only by structural regulation has good stability; The material of the lotus leaf-like nanostructure is alumina, which is used as a wear-resistant and corrosion-resistant coating for common workpieces. Therefore, the special-structure nano-alumina prepared by the micro-arc oxidation method in this embodiment also has excellent stability.

In step S10, in one embodiment, the steps of sequentially polishing and cleaning the aluminum or aluminum alloy include: polishing the aluminum or aluminum alloy with high-grit sandpaper, and polishing the polished aluminum or aluminum alloy The alloy is sequentially cleaned with deionized water, absolute ethanol or acetone for 10-30 minutes by ultrasonic cleaning.

In one embodiment, the aluminum or aluminum alloy may be pure aluminum, 2-series, 5-series, 6-series or 7-series aluminum alloy.

In step S20, in one embodiment, the alkaline electrolyte includes: 3-20 g/L phosphate, 1-5 g/L alkaline hydroxide, and the solvent is water (such as deionized water).

In a specific embodiment, the phosphate is selected from one or more of sodium hexametaphosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium tripolyphosphate, trisodium phosphate and sodium pyrophosphate.

In a preferred embodiment, in the alkaline electrolyte, the phosphate is 5 g/L sodium tripolyphosphate. The alkaline electrolyte prepared by 5g/L sodium tripolyphosphate has good dispersion effect, and can make liquid and solid particles better dissolve in the electrolyte, and play a solubilizing role in the micro-arc oxidation process , which is more conducive to obtaining a stable aluminum oxide film layer.

In a specific embodiment, the alkaline hydroxide is selected from one or more of sodium hydroxide and potassium hydroxide.

In one embodiment, the process conditions of the micro-arc oxidation treatment include:

The selected power supply is a pulse power supply. The operating parameters of the pulse power supply are: under constant current mode, the current density is 1-40A/dm ² , the frequency is 100-2000Hz, the duty cycle is 10-15%, and the micro-arc oxidation time is 1 -10min.

In a preferred embodiment, the current density is 2A/dm ² , because a moderate current density will balance the growth and corrosion process of the aluminum oxide film, and when the current density is too high, it will cause the aluminum oxide film to grow too Fast, easy to sinter, and not easy to corrode the lotus leaf-like nanostructure. When the current density is low, the aluminum oxide film grows slowly and densely, which is not conducive to corrosion.

In a preferred embodiment, the frequency is 200 Hz. If the frequency is too high, the aluminum oxide film will grow too fast. On the contrary, if the frequency is too small, it is not conducive to obtaining a dense aluminum oxide film and is not conducive to corrosion.

In a preferred embodiment, the micro-arc oxidation time is 5 minutes, which can ensure the ideal lotus-leaf-like nanostructures, and avoid excessive corrosion to cause structural damage.

The present invention will be further described below through several specific examples.

Example 1

Using 2A12 aluminum alloy as the aluminum source, cut it into a rectangular sample with a size of 50 mm × 25 mm × 2 mm, use commonly used 1200-mesh metallographic sandpaper to polish, and then use deionized water and absolute ethanol to ultrasonically clean for 30 minutes to obtain Samples are ready for use. Prepare the alkaline electrolyte system for micro-arc oxidation, including: 5g/L sodium tripolyphosphate, 1.5g/L sodium hydroxide, and the solvent is deionized water, which is placed in a stainless steel electrolyte container for use.

A pulse power supply is used in the micro-arc oxidation process, and the parameters of the power supply are adjusted as follows: in constant current mode, the current density is 2A/dm ² , the frequency is 200Hz, and the duty ratio is 12%. After adjusting the power supply parameters, use the aluminum alloy to be used as the anode, and the stainless steel electrolyte container as the cathode, turn on the power, and after micro-arc oxidation for 5 minutes, the aluminum alloy with an oxide layer is obtained, and finally rinse with deionized water and dry naturally, that is A superhydrophobic material with lotus leaf-like nano-alumina was obtained.

The front and cross-sectional SEM results of the material are shown in Figure 1 and Figure 2. It can be seen that the film layer is composed of randomly distributed irregular lotus leaf-like structures, most of which are disc-shaped, with an average diameter of about 500nm. There are gaps between the sheets in the range of 200-1200nm. From the cross-section of the material, it can be seen that the total thickness of the film layer with the lotus leaf-like nanostructure obtained is about 1 μm. The lotus leaf-like structure on the top of the film layer is not as smooth as the real lotus leaf, but has some wrinkles and unevenness on the surface, which is due to the rapid and violent reaction between the sample and the electrolyte under the arc discharge, and the growing film The surface of the layer will have a certain roughness, showing an uneven state. The lotus leaf layer structure at the top is supported by poles so that the structure does not collapse. Due to the corrosion of the electrolyte, the poles have different diameters and irregular shapes. The XRD results of the obtained material are shown in Figure 3. It can be seen that the characteristic peak of amorphous alumina appears on the aluminum sheet at the position of 15.1°-35.6°, which confirms that the surface of the 2A12 aluminum alloy has formed alumina after micro-arc oxidation treatment. Mutually. As shown in Figure 4, the measured contact angle of the material to water is 150±3°, showing superhydrophobicity. A 20-microliter water droplet was able to maintain a spherical shape on the surface of the material, confirming the uniform superhydrophobicity of the material.

Example 2

Using 5005 aluminum alloy as the aluminum source, cut it into a rectangular sample with a size of 50 mm × 25 mm × 2 mm, polish it with 1200-mesh metallographic sandpaper, and then use deionized water and absolute ethanol to ultrasonically clean it for 30 minutes to obtain Samples are ready for use. Prepare the alkaline electrolyte system for micro-arc oxidation, including: 5g/L sodium tripolyphosphate, 1.5g/L sodium hydroxide, and the solvent is deionized water, which is placed in a stainless steel electrolyte container for use.

A pulse power supply is used in the micro-arc oxidation process, and the parameters of the power supply are adjusted as follows: in constant current mode, the current density is 2A/dm ² , the frequency is 200Hz, and the duty ratio is 12%. After adjusting the power supply parameters, use the aluminum alloy to be used as the anode, and the stainless steel electrolyte container as the cathode, turn on the power, and after micro-arc oxidation for 5 minutes, the aluminum alloy with an oxide layer is obtained, and finally rinse with deionized water and dry naturally, that is A superhydrophobic material with lotus leaf-like nano-alumina was obtained.

Example 3

Using 6061 aluminum alloy as the aluminum source, cut it into a rectangular sample with a size of 50 mm × 25 mm × 2 mm, polish it with 1200-mesh metallographic sandpaper, and then use deionized water and absolute ethanol to ultrasonically clean it for 30 minutes to obtain Samples are ready for use. Prepare the alkaline electrolyte system for micro-arc oxidation, including: 5g/L sodium tripolyphosphate, 1.5g/L sodium hydroxide, and the solvent is deionized water, which is placed in a stainless steel electrolyte container for use.

A pulse power supply is used in the micro-arc oxidation process, and the parameters of the power supply are adjusted as follows: in constant current mode, the current density is 2.5A/dm ² , the frequency is 250Hz, and the duty ratio is 12%. After adjusting the power supply parameters, use the aluminum alloy to be used as the anode, and the stainless steel electrolyte container as the cathode, turn on the power, and after micro-arc oxidation for 5 minutes, the aluminum alloy with an oxide layer is obtained, and finally rinse with deionized water and dry naturally, that is A superhydrophobic material with lotus leaf-like nano-alumina was obtained.

Example 4

Using 7075 aluminum alloy as the aluminum source, cut it into a rectangular sample with a size of 50mm×25mm×2mm, polish it with 1200-mesh metallographic sandpaper, and then use deionized water and absolute ethanol to ultrasonically clean it for 30 minutes. Obtain samples for use. Prepare the alkaline electrolyte system for micro-arc oxidation, including: 5g/L sodium tripolyphosphate, 1.5g/L sodium hydroxide, and the solvent is deionized water, which is placed in a stainless steel electrolyte container for use.

A pulse power supply is used in the micro-arc oxidation process, and the parameters of the power supply are adjusted as follows: in constant current mode, the current density is 2A/dm ² , the frequency is 200Hz, and the duty ratio is 12%. After adjusting the power supply parameters, use the aluminum alloy to be used as the anode, and the stainless steel electrolyte container as the cathode, turn on the power, and after micro-arc oxidation for 5 minutes, the aluminum alloy with an oxide layer is obtained, and finally rinse with deionized water and dry naturally, that is A superhydrophobic material with lotus leaf-like nano-alumina was obtained.

Example 5

Using 2A12 aluminum alloy as the aluminum source, cut it into a rectangular sample with a size of 50mm×25mm×2mm, polish it with 1200-mesh metallographic sandpaper, and then use deionized water and absolute ethanol to ultrasonically clean it for 30 minutes to obtain Samples are ready for use. Prepare the alkaline electrolyte system for micro-arc oxidation, including: 5g/L sodium tripolyphosphate, 2.1g/L potassium hydroxide, and the solvent is deionized water, which is placed in a stainless steel electrolyte container for use.

A pulse power supply is used in the micro-arc oxidation process, and the parameters of the power supply are adjusted as follows: in constant current mode, the current density is 2A/dm ² , the frequency is 200Hz, and the duty ratio is 12%. After adjusting the power supply parameters, use the aluminum alloy to be used as the anode, and the stainless steel electrolyte container as the cathode, turn on the power, and after micro-arc oxidation for 5 minutes, the aluminum alloy with an oxide layer is obtained, and finally rinse with deionized water and dry naturally, that is A superhydrophobic material with lotus leaf-like nano-alumina was obtained.

In summary, the present invention provides a super-hydrophobic material and a preparation method thereof. By using micro-arc oxidation technology on aluminum or aluminum alloys, aluminum oxide with a lotus leaf-like nanostructure is prepared in one step in an alkaline electrolyte, realizing Synthesis of superhydrophobic alumina materials. Superhydrophobic alumina materials only rely on special micro-nano structures to achieve superhydrophobicity, and do not need to be modified by any organic low surface energy substances. The preparation method is simple and easy to operate, and the cost is low, which has potential application value.

It should be understood that the application of the present invention is not limited to the above examples, and those skilled in the art can make improvements or transformations according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. A superhydrophobic material, wherein the superhydrophobic material has a lotus-leaf-like nanostructure.

2. the superhydrophobic material of claim 1, wherein the superhydrophobic material is a metal oxide having a scalloped nanostructure.

3. The superhydrophobic material of claim 2, wherein the superhydrophobic material is alumina having a scalloped nanostructure.

4. The preparation method of the super-hydrophobic material is characterized in that the micro-arc oxidation technology is adopted to prepare the super-hydrophobic material with the lotus leaf-shaped nano structure.

5. The method for preparing the superhydrophobic material of claim 4, comprising the steps of:

Providing a metal substrate;

And forming a metal oxide with a lotus leaf-shaped nano structure on the metal base material by adopting a micro-arc oxidation technology to obtain the super-hydrophobic material.

6. The method for preparing the superhydrophobic material of claim 4, comprising the steps of:

Providing aluminum or aluminum alloy, and sequentially polishing and cleaning the aluminum or aluminum alloy;

Putting the treated aluminum or aluminum alloy into an alkaline electrolyte, connecting the aluminum or aluminum alloy with the anode of a power supply, connecting the cathode of the power supply with a working electrode, contacting the working electrode with the electrolyte, and starting the power supply to perform micro-arc oxidation treatment;

After micro-arc oxidation treatment, washing and drying are carried out, and aluminum oxide with a lotus leaf-shaped nano structure is obtained on the surface of aluminum or aluminum alloy, so that the super-hydrophobic material is obtained.

7. The method for preparing the superhydrophobic material of claim 6, wherein the alkaline electrolyte comprises: 3-20g/L of phosphate, 1-5g/L of alkaline hydroxide and water as a solvent.

8. The method of claim 7, wherein the phosphate is selected from one or more of sodium hexametaphosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium tripolyphosphate, trisodium phosphate, and sodium pyrophosphate.

9. The method for preparing a superhydrophobic material of claim 7, wherein the alkaline hydroxide is selected from one or more of sodium hydroxide and potassium hydroxide.

10. The preparation method of the super-hydrophobic material as claimed in claim 6, wherein the process conditions of the micro-arc oxidation treatment comprise:

The selected power supply is a pulse power supply, and the operating parameters of the pulse power supply are that the current density is 1-40A/dm ², the frequency is 100-2000Hz, the duty ratio is 10-15%, and the micro-arc oxidation time is 1-10min in a constant current mode.