Method for preparing super-hydrophobic surface and application of super-hydrophobic surface

Abstract

The invention discloses a method for preparing a super-hydrophobic surface and application of the super-hydrophobic surface. The method for preparing the super-hydrophobic surface comprises the following steps that (1) the style and parameters of a microstructure to be machined are designed, and then a picosecond laser is adopted for conducting laser machining on the surface of a stainless steel base material; and 2) carrying out surface modification treatment on the stainless steel base material by using fluorine-containing silane. According to the method, the circular-groove-shaped microstructure is prepared on the surface of the stainless steel base material through the picosecond laser melting machining technology, surface modification treatment is conducted through the fluorine-containing silane, the super-hydrophobic surface is obtained, flexible switching of the wetting characteristics of the super-hydrophobic surface can be achieved only by changing the scanning frequency of laser machining, and operation is easy.

Description

Technical Field

[0001] The invention relates to the technical field of bionic functional surfaces, and in particular to a method for preparing a super-hydrophobic surface and an application thereof. Background Art

[0002] A superhydrophobic surface is a surface with special wettability, and the static contact angle of a water drop on the surface exceeds 150°. Superhydrophobic surfaces can be divided into the following two categories according to the size of the rolling angle: a "lotus effect" superhydrophobic surface with a low rolling angle and a "petal effect" superhydrophobic surface with a high rolling angle. Superhydrophobic surfaces have been used in many fields such as self-cleaning, anti-adhesion, fog collection, anti-icing, corrosion resistance, non-destructive transfer of liquids, droplet sensors, etc., showing great application potential. At present, there are many processes for preparing superhydrophobic surfaces, mainly including photolithography, laser etching, 3D printing, electrodeposition, chemical deposition, etc., but the existing preparation processes generally have the problem of complicated steps, and usually can only prepare a single type of wettability surface, which is difficult to fully meet the requirements of practical applications.

[0003] Therefore, it is of great significance to develop a method for preparing superhydrophobic surfaces that is simple to operate and whose surface wetting properties can be flexibly switched. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a super-hydrophobic surface and application thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A method for preparing a super-hydrophobic surface comprises the following steps:

[0007] 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 the stainless steel substrate; the microstructure to be processed comprises a plurality of circular groove-shaped microstructures; the inner middle position of the circular groove-shaped microstructure contains a crater-shaped annular column protrusion, which together with the outer wall of the circular groove-shaped microstructure constitutes an inner and outer double-layer closed gas groove structure; the radius of the circular groove-shaped microstructure is 100 μm to 140 μm, and the spacing is 40 μm to 45 μm; the inner radius of the crater-shaped annular column protrusion is 20 μm to 50 μm, and the thickness of the annular column is 30 μm to 45 μm;

[0008] 2) The stainless steel substrate is surface modified using fluorinated silane.

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

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

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

[0012] Preferably, the process parameters of the laser processing 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 scanning times of 5 to 50 times.

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

[0014] Preferably, after the laser processing in step 1), the stainless steel substrate is ultrasonically cleaned and dried.

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

[0016] Preferably, the fluorine-containing 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) comprises the following operation: immersing the stainless steel substrate in a dispersion of fluorinated silane.

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

[0019] Preferably, the mass fraction of the fluorine-containing silane in the fluorine-containing silane dispersion 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 dried.

[0022] Preferably, the drying is carried out at a temperature of 140° C. to 160° C., and the drying time is 1 h to 2 h.

[0023] An application of the method for preparing a super-hydrophobic surface as described above in preparing a self-cleaning material, an anti-adhesion material, a fog collecting material, an anti-icing material, a corrosion-resistant material, a liquid lossless transfer material or a droplet sensor.

[0024] The beneficial effects of the present invention are as follows: the present invention utilizes a picosecond laser melting process to prepare a circular groove-shaped microstructure on the surface of a stainless steel substrate, and utilizes fluorinated silane for surface modification to obtain a super-hydrophobic surface, and only requires changing the number of scans of the laser processing to achieve flexible switching of the wetting characteristics of the super-hydrophobic surface (switching between a "lotus effect" super-hydrophobic surface with a low rolling angle and a "petal effect" super-hydrophobic surface with a high rolling angle), and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are the physical pictures and scanning electron microscope pictures of Oolong tea.

[0026] Figure 2 Schematic diagram of laser processing.

[0027] Figure 3 The scanning electron microscope images of the surface of the 304 stainless steel plate after laser scanning 5 times and 50 times in Example 1.

[0028] Figure 4 The contact angle and rolling angle test diagrams of the surface of the 304 stainless steel plate after laser scanning 5 times and 50 times in Example 1. DETAILED DESCRIPTION

[0029] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0030] Embodiment 1:

[0031] A method for preparing a super hydrophobic surface, the steps are as follows (inspired by the surface structure of oolong tea leaves, a super hydrophobic surface with a bionic structure is prepared; the physical picture and scanning electron microscope picture of oolong tea leaves are as follows Figure 1 As shown, a is a physical picture, b is a scanning electron microscope picture):

[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 the 304 stainless steel plate (length 30 mm, width 30 mm, height 1.5 mm) in pure water for ultrasonic cleaning for 10 min, the ultrasonic frequency is 28 kHz, and then place it in a blast drying oven for drying, and then use a picosecond laser to laser process the surface of the 304 stainless steel plate. The process parameters of the laser processing are as follows: the laser processing power is 10 W, the laser frequency is 500 kHz, the scanning speed is 500 mm / s, and the number of scans is 50 times (the laser processing schematic diagram is shown in Figure 2 As shown), the 304 stainless steel plate was then immersed in pure water for ultrasonic cleaning for 10 min, the ultrasonic frequency was 28 kHz, and then placed in a blast drying oven for drying;

[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 take out the 304 stainless steel plate and place it in a forced air drying oven at 150°C for 2 hours.

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

[0035] Depend on Figure 3 It can be seen that after 5 laser scans, a circular groove-like microstructure evenly arranged in an array appeared on the surface of the 304 stainless steel plate, and the depth was shallow. After 50 laser scans, the overall depth of the circular groove-like microstructure was significantly deeper.

[0036] The contact angle and rolling angle test diagrams of the surface of the 304 stainless steel plate after 5 and 50 laser scans in this embodiment are as follows: Figure 4 (a is the contact angle after 5 laser scans, b is the rolling angle after 5 laser scans, c is the contact angle after 50 laser scans, and d is the rolling angle after 50 laser scans).

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

[0038] a) After 5 laser scans, the contact angle of the 304 stainless steel plate surface is 149.7°±1.1°, and the rolling angle is 180°±0°. The droplets can adhere to the microstructure surface without falling off, indicating that a "petal effect" super hydrophobic surface with a high rolling angle is formed;

[0039] b) After 50 laser scans, the contact angle of the 304 stainless steel plate surface is 153.6°±1.2°, and the rolling angle is 6.9°±1.1°. The droplet can roll off the microstructure surface at a very small tilt angle, indicating that a "lotus leaf effect" super hydrophobic surface with a low rolling angle has been formed;

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

[0041] Embodiment 2:

[0042] A method for preparing a super-hydrophobic surface is identical to Example 1 except that the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion) are adjusted.

[0043] Embodiment 3:

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

[0045] Embodiment 4:

[0046] A method for preparing a super-hydrophobic surface is exactly the same as Example 1 except that the parameters of the microstructure to be processed (the side wall thickness of the crater-shaped annular column protrusion) are adjusted and the number of scans in step 1) is adjusted from "50 times" to "40 times".

[0047] Comparative Example 1:

[0048] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "7W" and adjusting the number of scans in step 1) from "50 times" to "20 times", the rest is exactly the same as Example 1.

[0049] Comparative Example 2:

[0050] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure), adjusting the laser processing power in step 1) from "10W" to "8W", and adjusting the number of scans in step 1) from "50 times" to "30 times", the rest is exactly the same as Example 1.

[0051] Comparative Example 3:

[0052] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "7W", and adjusting the number of scans in step 1) from "50 times" to "30 times", the rest is exactly the same as Example 1.

[0053] Comparative Example 4:

[0054] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "8W", and adjusting the number of scans in step 1) from "50 times" to "20 times", the rest is exactly the same as Example 1.

[0055] Comparative Example 5:

[0056] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion) and adjusting the number of scans in step 1) from "50 times" to "30 times", the rest is exactly the same as Example 1.

[0057] Comparative Example 6:

[0058] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "9W", and adjusting the number of scans in step 1) from "50 times" to "20 times", the rest is exactly the same as Example 1.

[0059] Comparative Example 7:

[0060] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion) and adjusting the laser processing power in step 1) from "10W" to "8W", the rest is exactly the same as Example 1.

[0061] Comparative Example 8:

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

[0063] Comparative Example 9:

[0064] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "8W" and adjusting the number of scans in step 1) from "50 times" to "40 times", the rest is exactly the same as Example 1.

[0065] Comparative Example 10:

[0066] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure and the side wall thickness of the crater-shaped annular column protrusion) and adjusting the laser processing power in step 1) from "10W" to "7W", the rest is exactly the same as Example 1.

[0067] Comparative Example 11:

[0068] A method for preparing a super-hydrophobic surface, except for adjusting the parameters of the microstructure to be processed (the radius of the circular groove microstructure, the inner radius of the crater-shaped annular column protrusion and the side wall thickness of the crater-shaped annular column protrusion), adjusting the laser processing power in step 1) from "10W" to "9W" and adjusting the number of scans in step 1) from "50 times" to "30 times", the rest is exactly the same as Example 1.

[0069] Performance Test:

[0070] The process parameters and product performances in Examples 1 to 4 and Comparative Examples 1 to 11 are summarized in the following table:

[0071] Table 1 Summary of design parameters, laser processing parameters and product performance of microstructures 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 the two) is 40 μm.

[0074] From Table 1, we can see that:

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

[0076] b) The contact angles of the treated 304 stainless steel plates in Comparative Examples 1 to 11 are all less than 145°, which do not belong to super hydrophobic surfaces;

[0077] In summary, the present invention can use a stainless steel substrate to prepare a super-hydrophobic surface, and 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.

[0078] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a super-hydrophobic surface, characterized in that: The following steps are involved: 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 the stainless steel substrate; the microstructure to be processed comprises a plurality of circular groove-shaped microstructures; the inner middle position of the circular groove-shaped microstructure contains a crater-shaped annular column protrusion, which together with the outer wall of the circular groove-shaped microstructure constitutes an inner and outer double-layer closed gas groove structure; the radius of the circular groove-shaped microstructure is 100 μm to 140 μm, and the spacing is 40 μm to 45 μm; the inner radius of the crater-shaped annular column protrusion is 20 μm to 50 μm, and the thickness of the annular column is 30 μm to 45 μm; 2) The stainless steel substrate is surface modified using fluorinated silane.

2. The method for preparing a super-hydrophobic surface according to claim 1, wherein: Step 1) The stainless steel substrate was ultrasonically cleaned and dried before use.

3. The method for preparing a super-hydrophobic surface according to claim 1 or 2, wherein: Step 1) The process parameters of the laser processing include: laser processing power of 9W to 10W, laser frequency of 450kHz to 550kHz, scanning speed of 450mm / s to 550mm / s, and scanning times of 5 to 50 times.

4. The method for preparing a super-hydrophobic surface according to claim 1 or 2, wherein: Step 1) The circular groove-shaped microstructures are arranged in an array.

5. The method for preparing a super-hydrophobic surface according to claim 1 or 2, wherein: After the laser processing in step 1), the stainless steel substrate is ultrasonically cleaned and dried.

6. The method for preparing a super-hydrophobic surface according to claim 1, wherein: Step 2) The fluorine-containing 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.

7. The method for preparing a super-hydrophobic surface according to claim 1 or 6, wherein: Step 2) The surface modification treatment comprises the following operations: immersing the stainless steel substrate in a dispersion containing fluorine-containing silane.

8. The method for preparing a super-hydrophobic surface according to claim 7, wherein: The soaking time is 2h to 4h.

9. The method for preparing a super-hydrophobic surface according to claim 1 or 6, wherein: After the surface modification treatment in step 2) is completed, the stainless steel substrate is dried.

10. Use of the method for preparing a super-hydrophobic surface as claimed in any one of claims 1 to 9 in preparing a self-cleaning material, an anti-adhesion material, a fog collecting material, an anti-icing material, a corrosion-resistant material, a liquid lossless transfer material or a droplet sensor.

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