A method for preparing superhydrophobic surfaces and its application

Abstract

The present invention discloses a method for preparing a super-hydrophobic surface and its application. The method for preparing a super-hydrophobic surface of the present invention comprises the following steps: 1) designing the style and parameters of the microstructure to be processed, and then using a picosecond laser to perform laser processing on the surface of a stainless steel substrate; 2) using fluorine-containing silane to perform surface modification treatment on the stainless steel substrate. The present invention uses a picosecond laser melting process to prepare a circular groove-shaped microstructure on the surface of a stainless steel substrate, and uses fluorine-containing silane to perform surface modification treatment to obtain a super-hydrophobic surface. The wetting characteristics of the super-hydrophobic surface can be flexibly switched by only changing the number of scans of the laser processing, and the operation is simple.

Description

Technical Field

[0001] This invention relates to the field of biomimetic functional surface technology, specifically to a method for preparing superhydrophobic surfaces and their applications. Background Technology

[0002] A superhydrophobic surface is a surface with exceptional wettability, where the static contact angle of a water droplet exceeds 150°. Superhydrophobic surfaces can be further categorized into two types based on their roll-off angle: low roll-off angle "lotus effect" superhydrophobic surfaces and high roll-off angle "petal effect" superhydrophobic surfaces. Superhydrophobic surfaces have been applied in numerous fields, including self-cleaning, anti-adhesion, fog collection, anti-icing, corrosion resistance, non-destructive liquid transfer, and droplet sensors, demonstrating enormous application potential. Currently, there are many processes for fabricating superhydrophobic surfaces, mainly including photolithography, laser etching, 3D printing, electrodeposition, and chemical deposition. However, existing fabrication processes generally suffer from cumbersome steps and typically can only produce a single type of wettable surface, making it difficult to fully meet practical application requirements.

[0003] Therefore, it is of great significance to develop a simple method for preparing superhydrophobic surfaces with flexible switching of surface wetting properties. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing superhydrophobic surfaces and their applications.

[0005] The technical solution adopted in this invention is:

[0006] A method for preparing a superhydrophobic surface includes the following steps:

[0007] 1) Design the style and parameters of the microstructure to be processed, and then use a picosecond laser to laser process the surface of the stainless steel substrate; the microstructure to be processed includes several circular groove-shaped microstructures; the inner center of each circular groove-shaped microstructure contains a crater-shaped annular column protrusion, which together with the outer wall of the circular groove-shaped microstructure forms an inner and outer double-layer closed gas groove structure; the radius of the circular groove-shaped microstructure is 100μm~140μm, and the spacing is 40μm~45μm; the inner radius of the crater-shaped annular column protrusion is 20μm~50μm, and the thickness of the annular column is 30μm~45μm;

[0008] 2) Surface modification treatment of stainless steel substrate is performed using fluorinated silane.

[0009] Preferably, the stainless steel substrate in step 1) is one of 304 stainless steel substrate and 316L stainless steel substrate.

[0010] Preferably, the stainless steel substrate described in step 1) is ultrasonically cleaned and dried before use.

[0011] Preferably, the ultrasonic cleaning includes the following operation: immersing the stainless steel substrate in water and ultrasonically cleaning it for 10 to 20 minutes at an ultrasonic frequency of 28 kHz to 40 kHz.

[0012] Preferably, the laser processing parameters in step 1) include: laser processing power of 9W to 10W, laser frequency of 450kHz to 550kHz, scanning speed of 450mm / s to 550mm / s, and number of scans of 5 to 50.

[0013] Preferably, the circular groove-shaped microstructures in step 1) are arranged in an array.

[0014] Preferably, after the laser processing in step 1) is completed, the stainless steel substrate is also subjected to ultrasonic cleaning and drying.

[0015] Preferably, the ultrasonic cleaning includes the following operation: immersing the stainless steel substrate in water and ultrasonically cleaning it for 10 to 20 minutes at an ultrasonic frequency of 28 kHz to 40 kHz.

[0016] Preferably, the fluorinated silane in step 2) is at least one of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, and tridecafluorooctyltriethoxysilane.

[0017] Preferably, the surface modification treatment in step 2) includes the following operation: immersing the stainless steel substrate in a dispersion of fluorinated silane for soaking.

[0018] Preferably, the solvent in the dispersion of the fluorinated silane is at least one selected from ethanol, methanol, n-propanol, isopropanol, and n-butanol.

[0019] Preferably, the mass fraction of fluorinated silane in the dispersion of fluorinated silane is 0.5% to 5.0%.

[0020] Preferably, the soaking time is 2 hours to 4 hours.

[0021] Preferably, after the surface modification treatment in step 2) is completed, the stainless steel substrate is also dried.

[0022] Preferably, the drying is carried out at a temperature of 140℃ to 160℃ for 1 hour to 2 hours.

[0023] The method for preparing a superhydrophobic surface as described above is applied in the preparation of self-cleaning materials, anti-adhesion materials, fog-collecting materials, anti-icing materials, corrosion-resistant materials, non-destructive liquid transfer materials, or droplet sensors.

[0024] The beneficial effects of this invention are: This invention utilizes picosecond laser melting processing technology to prepare a circular groove-shaped microstructure on the surface of a stainless steel substrate, and uses fluorinated silane for surface modification treatment to obtain a superhydrophobic surface. Moreover, the wettability of the superhydrophobic surface can be flexibly switched (switching between a low roll-off angle "lotus effect" superhydrophobic surface and a high roll-off angle "petal effect" superhydrophobic surface) simply by changing the number of laser processing scans, making the operation simple. Attached Figure Description

[0025] Figure 1 The images show actual oolong tea leaves and their scanning electron microscope (SEM) images.

[0026] Figure 2 This is a schematic diagram of laser processing.

[0027] Figure 3 The images are scanning electron microscope (SEM) images of the surface of a 304 stainless steel plate after 5 and 50 laser scans in Example 1.

[0028] Figure 4 The images show the contact angle and roll-off angle test results of the 304 stainless steel plate surface after 5 and 50 laser scans in Example 1. Detailed Implementation

[0029] The present invention will be further explained and described below with reference to specific embodiments.

[0030] Example 1:

[0031] A method for preparing a superhydrophobic surface, comprising the following steps (inspired by the surface structure of oolong tea leaves, a biomimetic superhydrophobic surface is prepared; physical images and scanning electron microscope images of oolong tea leaves are shown below). Figure 1 As shown in the image, a is a photograph of the actual object, and b is a scanning electron microscope image:

[0032] 1) Design the style and parameters of the microstructure to be processed (the design parameters of the microstructure to be processed are shown in Table 1). Then, immerse a 304 stainless steel plate (30mm long, 30mm wide, and 1.5mm high) in pure water for ultrasonic cleaning for 10 minutes at an ultrasonic frequency of 28kHz. Afterward, dry it in a forced-air drying oven. Then, use a picosecond laser to laser process the surface of the 304 stainless steel plate. The laser processing parameters are as follows: laser processing power of 10W, laser frequency of 500kHz, scanning speed of 500mm / s, and 50 scans (laser processing diagram shown in Table 1). Figure 2 (As shown), then immerse the 304 stainless steel plate in pure water for ultrasonic cleaning for 10 minutes at an ultrasonic frequency of 28kHz, and then place it in a forced-air drying oven to dry.

[0033] 2) Immerse the 304 stainless steel plate in an ethanol solution of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (the volume ratio of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane to ethanol is 1:100) for 3 hours, then remove the 304 stainless steel plate and place it in a forced-air drying oven at 150℃ for 2 hours.

[0034] The scanning electron microscope (SEM) images of the 304 stainless steel plate surface after 5 and 50 laser scans in this embodiment are shown below. Figure 3 (a represents 5 laser scans, b represents 50 laser scans) as shown.

[0035] Depend on Figure 3 It can be seen that after 5 laser scans, the surface of the 304 stainless steel plate shows a uniform array of circular groove-shaped microstructures with a shallow depth. After 50 laser scans, the overall depth of the circular groove-shaped microstructures is significantly deeper.

[0036] In this embodiment, the contact angle and roll-off angle test results of the 304 stainless steel plate surface after 5 and 50 laser scans are shown in the figure. Figure 4 (a is the contact angle after 5 laser scans, b is the roll angle after 5 laser scans, c is the contact angle after 50 laser scans, and d is the roll angle after 50 laser scans) as shown.

[0037] Depend on Figure 4 It can be known that:

[0038] a) After five laser scans, the contact angle of the 304 stainless steel plate surface was 149.7°±1.1° and the roll-off angle was 180°±0°. The droplets were able to adhere to the microstructure surface without falling off, indicating that a superhydrophobic surface with a high roll-off angle and "petal effect" was formed.

[0039] b) After 50 laser scans, the contact angle of the 304 stainless steel plate surface was 153.6°±1.2° and the roll-off angle was 6.9°±1.1°. The droplets were able to roll off the microstructure surface at a very small tilt angle, indicating that a "lotus effect" superhydrophobic surface with a low roll-off angle was formed.

[0040] In summary, the stainless steel plate surface exhibits different wetting characteristics after 5 and 50 laser scans, indicating that the microstructure of the stainless steel plate surface is different.

[0041] Example 2:

[0042] A method for preparing a superhydrophobic surface is identical to that in Example 1, except for adjusting the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion).

[0043] Example 3:

[0044] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (the inner radius of the crater-shaped annular protrusion) are adjusted and the laser processing power in step 1) is adjusted from "10W" to "9W".

[0045] Example 4:

[0046] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (the sidewall thickness of the crater-shaped annular protrusion) are adjusted and the number of scans in step 1) is changed from "50 times" to "40 times".

[0047] Comparative Example 1:

[0048] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "7W", and the number of scans in step 1) is adjusted from "50 times" to "20 times".

[0049] Comparative Example 2:

[0050] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure), the laser processing power in step 1) is adjusted from "10W" to "8W", and the number of scans in step 1) is adjusted from "50 times" to "30 times".

[0051] Comparative Example 3:

[0052] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (the inner radius of the crater-shaped annular protrusion and the sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "7W", and the number of scans in step 1) is adjusted from "50 times" to "30 times".

[0053] Comparative Example 4:

[0054] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (the inner radius of the crater-shaped annular protrusion and the sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "8W", and the number of scans in step 1) is adjusted from "50 times" to "20 times".

[0055] Comparative Example 5:

[0056] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion) are adjusted and the number of scans in step 1) is adjusted from "50 times" to "30 times".

[0057] Comparative Example 6:

[0058] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure and sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "9W", and the number of scans in step 1) is adjusted from "50 times" to "20 times".

[0059] Comparative Example 7:

[0060] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion) are adjusted and the laser processing power in step 1) is adjusted from "10W" to "8W".

[0061] Comparative Example 8:

[0062] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure and inner radius of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "7W", and the number of scans in step 1) is adjusted from "50 times" to "40 times".

[0063] Comparative Example 9:

[0064] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "8W", and the number of scans in step 1) is adjusted from "50 times" to "40 times".

[0065] Comparative Example 10:

[0066] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure and sidewall thickness of the crater-shaped annular protrusion) are adjusted and the laser processing power in step 1) is adjusted from "10W" to "7W".

[0067] Comparative Example 11:

[0068] A method for preparing a superhydrophobic surface is identical to Example 1, except that the parameters of the microstructure to be processed (radius of the circular groove microstructure, inner radius of the crater-shaped annular protrusion, and sidewall thickness of the crater-shaped annular protrusion), the laser processing power in step 1) is adjusted from "10W" to "9W", and the number of scans in step 1) is adjusted from "50 times" to "30 times".

[0069] Performance testing:

[0070] The process parameters and product performance of Examples 1-4 and Comparative Examples 1-11 are summarized in the table below:

[0071] Table 1 Summary of Design Parameters, Laser Processing Parameters, and Product Performance of the Microstructure to be Processed

[0072]

[0073] Note: The spacing between the circular groove microstructures (the distance between the edges of two adjacent circular groove microstructures, i.e., the shortest distance between them) is 40 μm.

[0074] As shown in Table 1:

[0075] a) The contact angle of the 304 stainless steel plate surface treated in Examples 1 to 4 is 151.18° to 164.56°, which is a superhydrophobic surface and exhibits excellent anti-wetting performance.

[0076] b) The contact angle of the treated 304 stainless steel plates in Comparative Examples 1 to 11 is less than 145°, which does not belong to superhydrophobic surfaces.

[0077] In summary, the present invention can prepare a superhydrophobic surface using a stainless steel substrate, and the wetting properties of the superhydrophobic surface can be flexibly switched simply by changing the number of laser scans, making the operation simple.

[0078] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a superhydrophobic surface, characterized in that, Includes the following steps: 1) Design the style and parameters of the microstructure to be processed, and then use a picosecond laser to laser process the surface of the stainless steel substrate; the microstructure to be processed includes several circular groove-shaped microstructures; the inner center of each circular groove-shaped microstructure contains a crater-shaped annular column protrusion, which together with the outer wall of the circular groove-shaped microstructure forms an inner and outer double-layer closed gas groove structure; the radius of the circular groove-shaped microstructure is 100μm~140μm, and the spacing is 40μm~45μm; the inner radius of the crater-shaped annular column protrusion is 20μm~50μm, and the thickness of the annular column is 30μm~45μm; 2) Surface modification treatment of stainless steel substrate using fluorinated silanes; Step 1) The laser processing parameters include: laser processing power of 9W to 10W, laser frequency of 450kHz to 550kHz, scanning speed of 450mm / s to 550mm / s, and number of scans of 5 to 50. Step 2) The fluorinated silane is at least one of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, and tridecafluorooctyltriethoxysilane. Step 2) The surface modification treatment includes the following operation: immersing the stainless steel substrate in a dispersion containing fluorinated silane for soaking; The soaking time is 2 to 4 hours.

2. The method for preparing a superhydrophobic surface according to claim 1, characterized in that: Step 1) The stainless steel substrate was ultrasonically cleaned and dried before use.

3. The method for preparing a superhydrophobic surface according to claim 1 or 2, characterized in that: Step 1) The circular groove-shaped microstructures are arranged in an array.

4. The method for preparing a superhydrophobic surface according to claim 1 or 2, characterized in that: Step 1) After the laser processing is completed, the stainless steel substrate is also subjected to ultrasonic cleaning and drying.

5. The method for preparing a superhydrophobic surface according to claim 1, characterized in that: Step 2) After the surface modification treatment is completed, the stainless steel substrate is dried.

6. The application of a method for preparing a superhydrophobic surface as described in any one of claims 1 to 5 in the preparation of self-cleaning materials, anti-adhesion materials, fog-collecting materials, anti-icing materials, corrosion-resistant materials, non-destructive liquid transfer materials, or droplet sensors.

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