CN110468415B - Preparation method and application of metal super-hydrophobic surface - Google Patents

Abstract

The invention relates to the field of preparation of superhydrophobic materials, in particular to a preparation method and application of a metal superhydrophobic surface. It includes the following steps: 1) using the set laser parameters and processing paths to perform laser processing on the surface of the polished and cleaned metal product to obtain a microstructure product; 2) putting the microstructure product into a mixed acid solution of a specific concentration , and carry out ultrasonic treatment to the acid solution containing the microstructured product, and remove the residual liquid on the product after completion; 3) carry out hydroxylation treatment to the microstructured product obtained in step (2); 4) carry out the hydroxylation treatment of step 3) The microstructured product is treated to reduce the surface energy, that is, it is obtained. The present invention prepares a regular and multi-featured microstructure that can be characterized on the surface of pure titanium, and the regular microstructure can be characterized by appropriate size elements, which provides a basis for subsequent research on the relationship between the wetting characteristics and the size of the microstructure. convenience.

Description

A kind of metal superhydrophobic surface preparation method and its application

technical field

The invention relates to the field of preparation of superhydrophobic materials, in particular to a preparation method and application of a metal superhydrophobic surface.

Background technique

The information disclosed in this Background of the Invention is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

In recent years, with the continuous development of bionics, the phenomenon of superhydrophobicity in nature has attracted more and more attention, and the most representative lotus leaf effect has gradually entered the field of vision of researchers. For the superhydrophobic self-cleaning properties of lotus leaves that are not stained, existing studies have shown that the main reason for this self-cleaning effect is due to the unique microstructure and chemical substances on the surface. Scanning electron microscope images show that the surface of lotus leaf has protrusions of 20-40 μm, and the micron-scale convex surface is accompanied by nano-scale particle features. This micro-nano composite structure reduces the contact area between droplets and the surface. Second, the waxy substances on the surface of lotus leaves are mainly composed of -C-H and -C-O bonds, and this material with low surface energy further reduces the adsorption force of droplets and pollutants on the surface. Therefore, the lotus leaf has a self-cleaning function under the dual action of the surface-specific structure and chemical substances.

Affected by the superhydrophobic effect, more and more superhydrophobic materials are used in practical life. For example, superhydrophobic metal surface modification can be applied to marine equipment. On the one hand, it reduces the corrosion rate of metals in the working environment and prolongs the service life of marine equipment; on the other hand, it reduces the resistance of underwater vehicles during navigation and improves navigation efficiency. . Secondly, superhydrophobic surface modification can also be applied to aerospace to improve the anti-icing ability of the material surface, reduce navigation resistance and improve navigation safety. Furthermore, the research on the wetting characteristics and biocompatibility of the surface of interventional medical materials has also attracted the attention of many researchers. By changing the hydrophilic and hydrophobic properties of the surface of medical materials, the adhesion of cells and blood proteins can be controlled, thereby improving the Biocompatibility of materials.

Due to the gradual maturity of precision manufacturing technology, electrochemical technology, lithography technology, etc., the research on realizing superhydrophobic function on the surface of different materials is also more in-depth and extensive. Two main factors are considered for the preparation of superhydrophobic surfaces. One is the microstructure of the surface of a reasonable structure material, which mainly includes the size and shape of the microstructure. Second, select the appropriate chemical treatment method to further reduce the surface energy of the material. At present, the existing methods for constructing the surface microstructure of materials on metal substrates mainly include micro-cutting, laser processing, plasma processing, electrochemistry, etc. Among them, the realization of micro-milling technology requires expensive micro-milling tools and high-precision machine tools. Furthermore, considering the tool size, processing efficiency and wear characteristics of micro-sized tools, the application of this technology to the preparation of micro-scale structures is limited. Plasma processing technology requires a complete set of supporting facilities in the process of realization, and the production cost is relatively high. In addition, according to the characteristics of electrochemical machining and other technologies, it is still difficult to realize the preparation of regular micro-scale structures.

SUMMARY OF THE INVENTION

The present invention believes that how to prepare a microstructured superhydrophobic surface with regularity and characterization is still a major challenge for current research. In view of the above problems, the present invention aims to provide a method for preparing a metal superhydrophobic surface and its application.

The first objective of the present invention is to provide a method for preparing a metal superhydrophobic surface.

The second object of the present invention is to provide the application of the method for preparing the metal superhydrophobic surface.

In order to realize the above-mentioned purpose of the invention, the present invention discloses the following technical solutions:

First, the present invention discloses a method for preparing a metal superhydrophobic surface, comprising the following steps:

(1) Laser processing: The surface of the polished and cleaned metal product is subjected to laser processing using the set ultraviolet laser parameters and processing path to obtain microstructure products; the laser parameters are: scanning speed 200-400mm/s, current 1A , frequency 40KHz, pulse width 16-20μs; the processing path parameters are: processing path distance 35-60μm, scanning times 3-14 times.

(2) Acid etching + ultrasonic treatment: put the microstructured product into a mixed acid solution formed by HF and HNO ₃ , and sonicate the acid solution containing the microstructured product.

(3) Hydroxylation treatment: carry out hydroxylation treatment on the microstructure product obtained in step (2).

(4) Surface energy reduction treatment: the surface energy reduction treatment is performed on the hydroxylated microstructure product in step (3) to obtain the result.

As a further technical solution, in step (1), the polishing and cleaning method is as follows: thermal inlay, physical polishing and ultrasonic cleaning are performed on the metal product.

As a further technical solution, the hot inlay temperature is 130°, the material is metallographic inlay powder, and the inlay time is 6-8 minutes.

As a further technical solution, the polishing is physical polishing, using 1200-mesh and 2000-mesh sandpaper for polishing in turn, and then using diamond polishing agent with particle size of 3.5μm and 1.5μm respectively for polishing, until the surface roughness of the sample metal product reaches Ra0.2-0.3μm.

As a further technical solution, the ultrasonic cleaning refers to sequentially cleaning the metal product with acetone, absolute ethanol and deionized water for 10 minutes each.

As a further technical solution, in step (1), the metal is pure titanium, and pure titanium can be used as a medical material after super-hydrophobic treatment on the surface, and the adhesion of cells and blood proteins can be achieved by controlling the hydrophilic and hydrophobic properties of the surface of the material. Control and improve the biocompatibility of materials.

As a further technical solution, in step (1), the laser processing adopts ultraviolet laser processing. This cold light source laser processing method not only produces less heat during processing, further reducing the processing heat-affected zone, but also has the advantages of low cost and high efficiency.

As a further technical solution, in step (2), the method for removing the residual liquid on the surface of the product is: the product is successively cleaned with acetone, absolute ethanol and deionized water for 8-12 minutes, and then at 50-60° Let it dry for 3-5 minutes.

As a further technical solution, in step (2), the parameters of the ultrasonic treatment are: the power is 240W, the ultrasonic frequency is 40KHz, and the treatment time is 3-5 minutes.

As a further technical solution, in step (2), the mixed acid solution includes the following components: 0.24-0.27wt% HF, 1.0-1.4wt% HNO ₃ , and the balance is deionized water. It is preferably 0.26wt% HF, 1.2wt% _HNO3 , and the balance is deionized water.

As a further technical solution, in step (3), the method of the hydroxylation treatment is: using ultraviolet irradiation for 2h.

As a further technical solution, in step (4), the method for reducing the surface energy treatment includes silanization treatment and the like.

As a further technical solution, the silanization treatment method is as follows: placing the hydroxylated microstructure product into a silane solution of a specific concentration for surface modification treatment, and then taking out the sample for high-temperature dehydration condensation treatment, that is, to obtain; The silane solution includes the following components: 1 wt % tridecafluorooctyltriethoxysilane, 10 wt % deionized water, 89 wt % absolute ethanol and 3-4 drops of NH ₃ ·H ₂ O; the treatment time is 6 -7h, the high-temperature dehydration and condensation treatment is as follows: treatment at 120-130° for 40-60 minutes.

Secondly, the present invention discloses the application of the metal superhydrophobic surface preparation method in the field of aerospace, the preparation of marine equipment, the preparation of medical materials, and the like.

One of the characteristics of the method for preparing the metal superhydrophobic surface proposed by the present invention is that: based on the ultraviolet laser, the processing heat is less, and the processing heat-affected zone can be further reduced. Microstructure, and the size of the microstructure is close to or even smaller than the size of the micron-scale convex structure of the lotus leaf. Based on the method mentioned in the present invention, the size of the surface microstructure can be changed in real time, so that the method of the present invention has the ability to study the microstructure. The ability to relate size to hydrophobic properties of material surfaces.

The second feature of the method for preparing the metal superhydrophobic surface proposed by the present invention is that the microstructure obtained by laser processing is processed by a combined method of acid etching and ultrasonic, wherein HF is easy to interact with the oxidized product (TiO ₂ / TiO) reacts to generate titanate and water, _HNO3 can further dissolve salt compounds and carbon impurities, and can improve the reaction efficiency of F- ⁱⁿ a strong acid environment. Secondly, ultrasonic treatment can make the metal slag on the surface of the microstructure react with acid more uniformly, and can prevent the product titanate from adhering to the machined surface, making the machined surface smooth and smooth, with a roughness of Ra0.2~0.35μm . Taking into account comprehensively, the treatment method reduces the acid content in the acid etching solution and the corrosion treatment time, improves the treatment efficiency, and further reduces the impact of the corrosion waste liquid on the environment.

The third characteristic of the method for preparing the metal superhydrophobic surface proposed by the present invention is that a regular and multi-featured microstructure that can be characterized is prepared, and the regular microstructure can be characterized by suitable size elements, and the microstructure prepared in the present invention is used. The microstructure method realizes the study of the relationship between the size of the microstructure and the surface wetting characteristics, and provides conditions for the subsequent study of the relationship between the wetting characteristics and the size of the microstructure.

Compared with the prior art, the present invention has achieved the following beneficial effects:

(1) The present invention prepares a regular and multi-featured microstructure that can be characterized on the surface of pure titanium, and the regular microstructure can be characterized by appropriate size elements, and the subsequent research on the relationship between wetting characteristics and microstructure size relationship provides convenience.

(2) The size of the microstructure prepared on the metal surface of the present invention is close to or even smaller than the size of the micron-scale convex structure of the lotus leaf; moreover, the method of the present invention only needs to prepare the micron-scale convex structure to obtain excellent superhydrophobicity. , without the need to prepare the micro-nano composite structure on the surface of the lotus leaf.

(3) The highest contact angle of the superhydrophobic surface prepared by the invention is as high as 170°, which realizes higher hydrophobicity than the existing superhydrophobic surface.

(4) The superhydrophobic surface prepared by the present invention has more stable hydrophobic properties, and the contact angle remains above 150° after 30min ultrasonic treatment.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a three-dimensional surface topography and a two-dimensional profile diagram after polishing and cleaning in Example 1 of the present invention.

FIG. 2 is a three-dimensional topography diagram and a two-dimensional profile diagram of the microstructure after the acid etching and ultrasonic treatment in Example 1 of the present invention.

FIG. 3 is a two-dimensional profile diagram of a three-dimensional topography of a microstructure after acid etching and ultrasonic treatment in Example 2 of the present invention.

FIG. 4 is a two-dimensional profile diagram of a three-dimensional topography diagram of a microstructure after the combined treatment of acid etching and ultrasound in Example 3 of the present invention.

FIG. 5 is a morphological diagram of a droplet on a superhydrophobic surface in Example 1 of the present invention.

6 is a morphological diagram of a droplet on a superhydrophobic surface in Example 2 of the present invention.

FIG. 7 is a morphological diagram of a droplet on a superhydrophobic surface in Example 3 of the present invention.

FIG. 8 shows the change trend of the surface contact angle of the superhydrophobic surface in Example 3 of the present invention after undergoing ultrasonic treatment for different times.

FIG. 9 is the variation trend of the surface contact angle of the microstructure obtained at different depths in Example 4 of the present invention.

FIG. 10 is the variation trend of the surface contact angle of the microstructure obtained by the side lengths of the convex quadrilaterals of different sizes in Example 4 of the present invention.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, Indicates the presence of features, steps, operations, devices, components, and/or combinations thereof.

As mentioned above, the existing methods of micro-cutting, laser machining, plasma machining, electrochemistry, etc. to construct the surface microstructure of materials on metal substrates are still unable to achieve the preparation of microstructured superhydrophobic surfaces with regularity and characterization. Therefore, the present invention proposes a method for preparing a metal superhydrophobic surface; the present invention will now be further described with reference to the accompanying drawings and specific embodiments.

Example 1

A method for preparing a metal superhydrophobic surface, comprising the following steps:

(1) Sample cleaning and polishing: Prepare pure titanium (BT1-00, purity not less than 99.8%) sample size 10mm×10mm×2.5mm, and mount and polish the sample. The setting temperature is 130°, and the setting time is 6-8 minutes. The polishing method is as follows: use 1200-mesh and 2000-mesh sandpaper for polishing in turn, and then use diamond polishing agents with particle sizes of 3.5 μm and 1.5 μm for polishing until the surface roughness of the sample reaches Ra0.2-0.3 μm.

(2) Ultraviolet laser processing (model XCGX-3W): The polished and cleaned samples are placed on the processing platform for laser processing; among them, the processing parameters are: scanning speed 400mm/s, current 1A, frequency 40KHz, pulse width 16μs . The machining path distance was 35 μm, and the number of scans was 10 times.

(3) Slag acid etching treatment: put the laser-processed sample into the prepared mixed acid solution, and the mixed acid solution includes the following components: 0.26wt% HF, 1.2wt% HNO ₃ , the balance for deionized water. The acid etching process was combined with ultrasonic oscillation. The ultrasonic power was 240W, the ultrasonic frequency was 40KHz, and the treatment time was 5 minutes. The surface of the sample was observed by an optical microscope until the surface of the microstructure was smooth and bright and the slag disappeared. The samples were then washed in acetone, absolute ethanol and deionized water for 10 minutes each and finally dried at 60° for 5 minutes.

(4) Hydroxylation treatment on the surface of the sample: the dried sample is irradiated under an ultraviolet lamp for 2 h.

(5) Silanation treatment of the sample: put the hydroxylated sample into the prepared silane solution (100ml) for treatment, and the silane solution composition is 1wt% of tridecafluorooctyltriethoxysilane+10wt% Deionized water + 89wt% absolute ethanol and 4 drops of NH ₃ ·H ₂ O, the treatment time is 6h, after completion, the sample is subjected to high-temperature dehydration condensation treatment, the temperature is 130 °, and the treatment time is 40 minutes. A medical pure titanium superhydrophobic surface with regular multi-featured microstructure.

Example 2

A method for preparing a metal superhydrophobic surface is the same as the embodiment, except that: in step (2), the number of scans is 12, and the mixed acid solution includes the following components: 0.24wt% HF, 1.0wt% HF HNO ₃ , the balance being deionized water.

Example 3

A method for preparing a metal superhydrophobic surface is the same as the embodiment, except that: in step (2), the number of scans is 14 times, and the mixed acid solution includes the following components: 0.27wt% HF, 1.4wt% HF HNO ₃ , the balance being deionized water.

Performance Testing:

Referring to Figure 1, the surface roughness of the pure titanium sample after polishing and cleaning is about Ra0.2-0.3 μm.

Figures 2, 3, and 4 show the multi-feature microscale structures prepared in Examples 1-3, respectively, in which the length of the regular convex quadrilateral is about 10 μm, and the groove depths are about 15 μm, 19 μm and 15 μm due to the different processing times, respectively. 22.5μm, its size is close to or even smaller than the size of the micro-protrusions on the surface of the lotus leaf. This regular microstructure surface preparation technology realizes the low-cost preparation of a biomimetic structure surface of the same size on the metal surface. Surface wetting properties offer possibilities.

Figures 5, 6, and 7 show the droplet wetting state diagrams of the modified surfaces in Examples 1-3, respectively. As the depth increases, the contact angle increases from 158.8° to 170°, fully possessing the superhydrophobicity. The contact angle of the surface, especially Example 3, is already close to the limit value of 180°.

Figure 8 shows the change trend of the surface contact angle of the superhydrophobic surface prepared in Example 3 after undergoing ultrasonic treatment for different times. The ultrasonic power involved in the ultrasonic treatment is 240W, the frequency is 40KHz, each ultrasonic treatment is 10min, and the surface contact angle is measured after being placed for 17h. Among them, after accumulative ultrasonic treatment for 30min and standing for 48-50h, the surface contact angle of the sample remains above 150°, which is enough to show that the superhydrophobic surface prepared by the method of the present invention has high stability.

Example 4

By changing the laser processing parameters, microstructured surfaces with different depths and different side lengths of raised quadrilaterals were obtained. Figure 9 shows the relationship between the depth of the microstructure and the surface wetting characteristics. It can be seen from Figure 9 that with the increasing depth, the surface hydrophobicity continues to improve. But when the depth increased to 20 μm, the hydrophobicity of the surface improved slowly. Figure 10 shows the effect of raised edge length on the surface wetting properties in the microstructure. It can be clearly seen from Fig. 10 that as the side length of the raised square increases, the hydrophobic property of the surface decreases continuously. When the side length is less than 20 μm, the change of the wetting property is not obvious. The research on the relationship between structure size and wetting characteristics in Fig. 9 and Fig. 10 can provide a reference for the later preparation of micron-scale superhydrophobic surfaces.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (12)

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

(1) laser processing: carrying out laser processing on the surface of the polished and cleaned metal product by adopting set laser parameters and a processing path to obtain a microstructure product; the laser parameters are: the scanning speed is 200-; the processing path parameters are as follows: the distance of the processing path is 35-60 μm, and the scanning times are 3-14;

(2) acid etching and ultrasonic treatment: placing the microstructured product in HF and HNO₃In the formed mixed acid solution, carrying out ultrasonic treatment on the acid solution containing the microstructure product, and removing residual liquid on the product after the ultrasonic treatment is finished;

(3) hydroxylation treatment: carrying out hydroxylation treatment on the microstructure product obtained in the step (2);

(4) and (3) surface energy reduction treatment: carrying out surface energy reduction treatment on the hydroxylated microstructure product in the step (3) to obtain the product;

in the step (1), the laser processing adopts ultraviolet laser processing;

in the step (4), the surface energy reducing treatment method comprises silanization treatment;

the silanization treatment method comprises the following steps: putting the hydroxylated microstructure product into a silane solution with a specific concentration for surface modification treatment, and taking out a sample for high-temperature dehydration condensation treatment to obtain the product; the silane solution comprises the following components: 1 wt% of tridecafluorooctyltriethoxysilane, 10 wt% of deionized water, 89 wt% of anhydrous ethanol and 3-4 drops of NH₃·H₂O; the treatment time is 6-7h, and the high-temperature dehydration condensation treatment comprises the following steps: the treatment is carried out at 120-130 ℃ for 40-60 minutes.

2. The method for preparing the metal superhydrophobic surface according to claim 1, wherein in the step (2), the method for removing the residual liquid on the surface of the product comprises: and sequentially washing the product with acetone, absolute ethyl alcohol and deionized water for 8-12 minutes respectively, and then drying at 50-60 ℃ for 3-5 minutes to obtain the product.

3. The method for preparing the metal superhydrophobic surface according to claim 1, wherein in the step (2), the parameters of the ultrasonic treatment are as follows: the power is 240W, the ultrasonic frequency is 40KHz, and the processing time is 3-5 minutes.

4. The method for preparing a metallic superhydrophobic surface according to claim 1, wherein in the step (2), the mixed acid solution comprises the following components: 0.24-0.27 wt% of HF,1.0-1.4 wt% of HNO₃And the balance of deionized water.

5. The method for preparing a metallic superhydrophobic surface according to claim 4, wherein the mixed acid solution comprises the following components: 0.26 wt% HF,1.2 wt% HNO₃And the balance of deionized water.

6. The method for preparing a metal superhydrophobic surface according to claim 1, wherein in the step (3), the hydroxylation treatment method comprises: treating with ultraviolet irradiation for 2 h.

7. The method for preparing a metallic superhydrophobic surface according to any one of claims 1-6, wherein in the step (1), the metal is pure titanium.

8. The method for preparing a metal superhydrophobic surface according to any one of claims 1-6, wherein in the step (1), the polishing and cleaning method comprises: and carrying out thermal inlaying, physical polishing and ultrasonic cleaning on the metal product.

9. The method for preparing a metal superhydrophobic surface according to claim 8, wherein the thermal inlaying temperature is 130 ℃, the material is metallographic inlaying powder, and the inlaying time is 6-8 minutes.

10. The method for preparing a metal superhydrophobic surface according to claim 8, wherein the polishing is physical polishing, and 1200-mesh and 2000-mesh sandpaper are sequentially used for polishing, and then diamond polishing agents with the grain sizes of 3.5 μm and 1.5 μm are respectively used for polishing until the surface roughness of the sample metal product reaches Ra0.2-0.3 μm.

11. The method for preparing a metal superhydrophobic surface according to claim 8, wherein the ultrasonic cleaning is to sequentially clean the metal product with acetone, absolute ethyl alcohol and deionized water for 10 minutes.

12. The use of the method of any one of claims 1 to 11 for the preparation of a metal superhydrophobic surface in the aerospace field, in the preparation of marine devices, and in the preparation of medical materials.

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