Super-hydrophobic surface preparation method and device based on laser-induced deep etching and super-hydrophobic surface film thereof
Through laser-induced deep etching technology, the pulsed Gaussian beam is converted into a Bessel beam, and combined with corrosion and mold turn steps, the problems of slow processing speed and reduced transparency in the existing technology are solved, achieving high efficiency and accurate large-scale Area produces high transparency superhydrophobic surfaces.
Patent Information
- Application Number
- CN202411185764.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2024-12-10
AI Technical Summary
The prior art has problems of slow processing speed, poor accuracy and reduced transparency when manufacturing superhydrophobic surfaces, especially in large-area and large-scale production, which is difficult to achieve efficient and high-quality micro-nano structure processing.
Using a laser-induced deep etching method, the pulsed Gaussian beam is converted into a Bessel beam, and by controlling the laser pulse energy and focus position, combining the corrosion and mold turn steps of potassium hydroxide solution, the material modification at high speed and large focal depth is achieved. Mass production of superhydrophobic surfaces with high transparency.
It improves processing efficiency and accuracy, obtains a superhydrophobic surface with high transparency and high transparency, while reducing processing costs and cycles, and is suitable for large-area and large-scale production.
Smart Images
Figure CN119100609A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to laser processing, and relates to a method and device for preparing a super-hydrophobic surface based on laser-induced deep etching, and a super-hydrophobic surface film. Background Art
[0002] Superhydrophobic surfaces have attracted widespread attention due to their wide range of applications in self-cleaning, anti-icing, and droplet manipulation. These surfaces exhibit superhydrophobicity mainly due to their low surface energy and the presence of micro / nanoscale roughness. In order to achieve these properties, two typical strategies are usually adopted: applying a low surface energy coating on the surface or directly designing microstructures on the material surface to increase the surface roughness. However, according to Mie scattering, an increase in surface roughness theoretically leads to a decrease in surface transparency, which means that micrometer-scale surface structures will reduce transparency in the visible light band. The loss of transparency can be avoided to a certain extent by precisely controlling the surface roughness and the arrangement position of the surface microstructures, but it remains a daunting challenge to accurately and quickly manufacture superhydrophobic microstructures with an ideal layout.
[0003] Ultrafast lasers have extremely high peak power density and can produce nonlinear multi-photon absorption in transparent materials. They can change the physical and chemical properties of materials in a very short time. By focusing the pulsed laser beam, a large number of micro-nano structures can be processed in a short time. At the same time, the size and shape of these micro-nano structures can be precisely controlled by controlling the laser pulse energy and focal position.
[0004] In recent years, the application of ultrafast laser in the production of super-hydrophobic surfaces has attracted the attention of more and more researchers. At present, many researchers use ordinary microscope objective focusing or galvanometer scanning to process, and have achieved good results, but this method also has some inevitable disadvantages:
[0005] (1) Since the focal depth of the microscope objective lens is small, it takes a long time to process a microstructure, which is not conducive to large-area rapid processing.
[0006] (2) Traditional laser processing is performed by direct ablation of the material. This process is greatly affected by the heat of the laser, and material debris will splash, affecting the accuracy of the processing.
[0007] (3) The laser direct processing speed is directly affected by the displacement platform speed or the galvanometer scanning speed. The processing speed is slow and the processing area is relatively limited. It is not suitable for large-scale and large-area processing. Summary of the invention
[0008] In view of the defects of the prior art, the present invention provides a method and device for preparing a super-hydrophobic surface based on laser-induced deep etching and a super-hydrophobic surface film thereof. Through beam shaping technology, the pulsed Gaussian beam is converted into a Bessel beam, and the pulse energy of the laser is controlled below the ablation threshold of the material to achieve high-speed and large focal depth material modification. Through subsequent corrosion and repeated mold turning steps, super-hydrophobic surfaces with high transparency can be produced in batches. The method has a stable and reliable process and a wide range of applications.
[0009] To achieve the above purpose, the technical solution of the present invention is as follows:
[0010] First, the present invention provides a method for preparing a super-hydrophobic surface based on laser-induced deep etching, which is characterized in that it includes:
[0011] Step 1. Focusing the pulse-shaped Bessel beam onto the surface of the glass mold for local modification;
[0012] Step 2: using potassium hydroxide solution to corrode the modified glass mold to form holes;
[0013] Step 3. Using polydimethylsiloxane or polymethyl methacrylate to re-mold the etched glass mold;
[0014] Step 4. Peel off the cured film to obtain a highly transparent super-hydrophobic surface.
[0015] Preferably, the step 1. further comprises:
[0016] Step 1.1 using a laser to emit ultrafast laser pulses;
[0017] Step 1.2: expanding and collimating the ultrafast laser pulse using a beam expansion and collimation system;
[0018] Step 1.3: shaping the ultrafast laser pulse using a beam shaping system to form a Bessel beam;
[0019] In step 1.4, a focusing system is used to focus the Bessel beam onto the surface of the glass mold for local modification.
[0020] Preferably, the step 2. further comprises:
[0021] At the same time, water bath heating is performed to improve the etching efficiency, and the size of the formed holes is controlled by controlling the etching time.
[0022] Preferably, the step 3. further includes:
[0023] The etched glass mold is cleaned and dried, and polydimethylsiloxane is poured thereon;
[0024] The cast glass mold is placed on a heating plate to accelerate the curing of the polydimethylsiloxane;
[0025] After the curing is completed, the polydimethylsiloxane film is peeled off to obtain a highly transparent super-hydrophobic film.
[0026] Preferably, the step 3. further includes:
[0027] The etched glass mold is cleaned and dried, and a preheated soft polymethyl methacrylate substrate is placed on the glass mold;
[0028] Apply pressure to the glass mold and substrate according to a preset pressure curve and continue for a certain period of time;
[0029] After the polymethyl methacrylate substrate is cooled, it is peeled off to obtain a non-flexible high-transparency super-hydrophobic film.
[0030] Second, the present invention also provides a super hydrophobic surface, which is characterized in that it is prepared using the preparation method described above.
[0031] Preferably, the diameter of the hole microstructure is less than 30 μm and the depth is greater than 60 μm.
[0032] Thirdly, the present invention also provides a device for implementing the above method based on laser-induced deep etching of super-hydrophobic surface, which is characterized in that it includes:
[0033] A laser emitting device configured to emit a pulse-shaped Bessel beam and perform a modification on the glass surface;
[0034] Water bath heating equipment, used to etch and water bath heat the modified glass to form holes;
[0035] A mold-turning material supply device configured to supply polydimethylsiloxane or polymethyl methacrylate for mold-turning processing;
[0036] The film stripping device is used to strip the polydimethylsiloxane film or the polymethyl methacrylate film from the cured glass mold to obtain a super-hydrophobic surface.
[0037] Preferably, the laser emitting device includes a laser, a beam expander collimator, a first reflector, a second reflector, a conical lens, a convex lens, a third reflector and a microscope objective lens which are placed in sequence along the laser output direction of the laser, and shapes the incident pulsed Gaussian beam to form a Bessel beam, and focuses it onto the glass surface through the convex lens and the microscope objective lens for modification.
[0038] The shape, arrangement and spacing of the microstructure can be adjusted according to the requirements of hydrophobicity, transparency and anti-friction.
[0039] The shape of the microstructure can be controlled by adjusting the laser pulse energy and etching time used in step 1 and step 2. A hole with a higher depth-to-diameter ratio can be obtained on the mold with higher energy and shorter etching time, and a hole with a lower depth-to-diameter ratio can be obtained on the mold with lower energy and longer etching time. By adjusting the process parameters, the ratio of the height of the microstructure to the bottom diameter can be controlled between 2:1 and 6:1.
[0040] The arrangement of the microstructures and the control of the arrangement spacing are achieved by controlling the repetition frequency of the laser pulse and the moving path of the displacement platform in step 1. By precisely controlling the trigger position of the laser pulse, the glass mold can be locally modified according to the processing requirements, and the position error of the laser modification is less than 2μm.
[0041] Compared with the prior art, the present invention mainly has the following advantages:
[0042] 1. The present invention uses Bessel beam to modify the glass mold, which increases the depth of laser focus and speeds up the modification efficiency. Single pulse modification improves the overall processing efficiency.
[0043] 2. Combining laser technology with wet etching process to form the hole, so that the hole edge is smooth and there is no recast layer caused by laser thermal effect.
[0044] 3. The super-hydrophobic film is prepared by the mold-turning method, and the mold can be reused, which reduces the processing cost and processing cycle.
[0045] 4. The optimized microstructure shape and arrangement are used to achieve surface super-hydrophobicity while improving the transparency and anti-friction performance of the film. BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Figure 1 It is a flow chart of the method for preparing a super-hydrophobic surface based on laser-induced deep etching of the present invention;
[0047] Figure 2 It is a laser modification device used in the embodiment of the present invention;
[0048] In the figure: 1. Laser; 2. Laser beam before beam expansion; 3. Beam expansion collimator; 4. Laser beam after beam expansion; 5. First reflector; 6. Second reflector; 7. Conical lens; 8. Convex lens; 9. Third reflector; 10. Microscope objective; 11. Glass mold; 12. Displacement platform
[0049] Figure 3 This is a micrograph of a glass porous mold made using the method of the present invention.
[0050] Figure 41 is a hydrophobic film made by the method of the present invention, wherein (a) is a microscopic image of the hydrophobic film, and (b) is a real image.
[0051] Figure 5 The microstructures formed on the high-transparency super-hydrophobic film produced by the method of the present invention are shown in FIG. 1 , wherein (a) is a microstructure with a lower aspect ratio, and (b) is a microstructure with a higher aspect ratio.
[0052] Figure 6 The figures are performance test diagrams of the high-transparency super-hydrophobic film made by the present invention, wherein (a) is a hydrophobicity test and (b) is a transparency test.
[0053] Figure 7 The figures are performance test diagrams of the high-transparency super-hydrophobic film made by the present invention, wherein (a) is a hydrophobicity test and (b) is a transparency test.
[0054] Figure 8 The highly transparent super hydrophobic film with a protective structure and its corresponding mold are made by using the present invention, wherein (a) is a current image of the glass mold, and (b) is a microscopic image of the hydrophobic film. DETAILED DESCRIPTION
[0055] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.
[0056] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The experimental methods without specific conditions in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all percentages, ratios, proportions or parts are by weight.
[0057] Unless otherwise specified, the reagents and raw materials used in the examples and comparative examples of the present invention can be obtained through commercial channels.
[0058] Build a laser modification device, such as Figure 2As shown, it includes: a laser for emitting ultrafast laser pulses, a beam expander collimator for expanding and collimating the laser beam, a first reflector and a second reflector for fine-tuning the laser beam so that the laser beam enters the field mirror vertically, a conical lens for beam shaping, a convex lens and a microscope objective lens for scaling and focusing the beam, and a displacement platform for adjusting the position of the glass so that the laser focus is on the inner wall of the glass. Among them, the number of reflectors can be increased or the angle of the reflectors can be adjusted as needed to adjust the optical path, which is convenient for practical application. When working, the laser beam 2 emitted by the laser 1 is expanded and collimated by the beam expander collimator 3, and then reflected by the first reflector 5 and the second reflector 6 to the conical lens 7, and then irradiated to the glass material 11 placed on the displacement platform 12 through the convex lens 8, the reflector 9 and the microscope objective lens 9. The beam expander and collimator 3 is used to expand and collimate the laser beam 2 output by the laser 1. The first reflector 5 and the second reflector 6 are used to guide the second laser beam 4 after expansion and collimation into the conical lens 7 for beam shaping, and then the beam is scaled and focused by the 4f system composed of the convex lens 8 and the microscope objective 10 to form a focused laser beam.
[0059] Example 1: Preparation of highly transparent super-hydrophobic surface
[0060] A femtosecond laser with an output wavelength of 1064nm, a pulse width of 15ps, a maximum output power of 70W, and a repetition frequency of 30-300KHz is used to make a porous mold with a thickness of 1mm using fused quartz glass. The laser is focused inside the glass and emitted from the lower surface, and the modified depth is 80μm. The single pulse energy of the target laser is set to 250μJ, the pulse trigger frequency is set to 1KHz, and the bow-shaped path with a spacing of 0.1mm is scanned at a speed of 100mm / s; then the modified glass mold is immersed in a 60% potassium hydroxide aqueous solution and heated in a water bath for 12h; after completion, a porous glass mold with a pore spacing of 100μm, a pore diameter of 30μm, and a pore depth of 80μm can be obtained. The surface appearance of the glass mold is as follows Figure 3 As shown in the figure, the holes are circular and neatly arranged, and the mold surface is relatively smooth. The mold is cast with polydimethylsiloxane, and a highly transparent super-hydrophobic film can be obtained after curing. Figure 4 As shown in (a) and (b).
[0061] Example 2: Optimization design of hydrophobic film surface microstructure
[0062] According to the Cassie-Baxter model, the hydrophobicity of the surface is related to the shape and arrangement of the microstructures on the surface. Based on the above Example 1, the shape of the microstructure can be controlled by precisely adjusting the laser pulse energy and the subsequent etching time. Figure 5(a) and (b) show two microstructure morphologies made with different processing parameters. The static contact angle and rolling angle of water droplets on the surface of the super-hydrophobic film were measured using a contact angle meter to evaluate its hydrophobic properties. The light transmittance of the super-hydrophobic film was measured using a spectrophotometer. Figure 6 As shown in (a) and (b), the change of the aspect ratio of the microstructure has an impact on the hydrophobicity and transparency of the film within a certain range, which is manifested as the higher the aspect ratio, the better the hydrophobic effect and the better the transparency. Preferably, the aspect ratio of the microstructure is set at 5:1 to obtain better hydrophobicity and higher transparency.
[0063] The arrangement spacing of the microstructures can be adjusted by precisely controlling the moving speed of the displacement platform and the repetition frequency of the laser. The static contact angle and rolling angle of a water drop on the surface of the super-hydrophobic film are measured using a contact angle meter to evaluate its hydrophobic properties. The light transmittance of the super-hydrophobic film is measured using a spectrophotometer. Figure 7 As shown in (a) and (b), the change of the microstructure arrangement spacing has an impact on the hydrophobic performance and transparency of the film within a certain range, which is manifested in that the smaller the microstructure arrangement spacing, the smaller the rolling angle, but the transparency will be reduced. Preferably, the microstructure arrangement spacing can be set to 140μm, at which time the static contact angle of the hydrophobic film can reach up to 153° and retain 99.23% transparency (@300nm-1100nm).
[0064] Example 3: Introducing a protective structure
[0065] On the basis of the above-mentioned embodiment 1, further, a microstructure with a groove morphology is made on the glass mold, which can improve the anti-friction performance of the hydrophobic film. The surface morphology of the glass mold is as follows: Figure 8 As shown in (a), these grooves are surrounded by holes in a square shape, with a hole pitch of 150 μm, a hole diameter of 25 μm, a hole depth of 80 μm, a groove width of 25 μm, and a groove depth of 70 μm. Figure 8 As shown in (b), after the same molding steps, a super-hydrophobic transparent film with a protective structure can be obtained. These protective protruding structures can effectively bear the external pressure, thereby protecting the internal microstructure. After testing, after 200 sandpaper frictions, the static contact angle of the hydrophobic film can still be higher than 140°.
[0066] Example 4: The shape of the mold hole can be changed
[0067] On the basis of the above-mentioned embodiment 1, a blind hole with a cylindrical profile can be made on a glass mold by adjusting the energy distribution of the Bessel beam and using etching liquids of other concentrations.
[0068] Example 5: The mold material can be replaced
[0069] On the basis of the above-mentioned Example 1, Example 2 and Example 3, a relatively hard and highly transparent hydrophobic film can be obtained by using a polymethyl methacrylate substrate to replicate the hydrophobic pattern through a hot pressing process.
[0070] The glass material in the present invention can be fused quartz glass or other glass that can be corroded by potassium hydroxide solution. After changing the glass material, the specific processing parameters also need to be adjusted, but the manufacturing method remains unchanged. The thickness of the glass material is usually 1 mm.
[0071] It should be pointed out that the above embodiments are intended to facilitate understanding of the technical solutions of the present invention rather than to limit them; any modification, equivalent substitution and improvement of the present invention are within the protection scope of the present invention.
Claims
1. A method for preparing a super-hydrophobic surface based on laser-induced deep etching, characterized in that: include: Step 1. Focusing the pulse-shaped Bessel beam onto the surface of the glass mold for local modification; Step 2: using potassium hydroxide solution to corrode the modified glass mold to form holes; Step 3. Use polydimethylsiloxane or polymethyl methacrylate to re-mold the etched glass mold; Step 4. Peel off the cured film to obtain a highly transparent super-hydrophobic surface.
2. The method for preparing a super-hydrophobic surface based on laser-induced deep etching according to claim 1, characterized in that: The step 1. also includes: Step 1.1 using a laser to emit ultrafast laser pulses; Step 1.2: expanding and collimating the ultrafast laser pulse using a beam expansion and collimation system; Step 1.3: shaping the ultrafast laser pulse using a beam shaping system to form a Bessel beam; In step 1.4, a focusing system is used to focus the Bessel beam onto the surface of the glass mold for local modification.
3. The method for preparing a super-hydrophobic surface based on laser-induced deep etching according to claim 1, characterized in that: The step 2. also includes: At the same time, water bath heating is performed to improve the etching efficiency, and the size of the formed holes is controlled by controlling the etching time.
4. The method for preparing a super-hydrophobic surface based on laser-induced deep etching according to claim 1, characterized in that: The step 3. also includes: The etched glass mold is cleaned and dried, and polydimethylsiloxane is poured thereon; The cast glass mold is placed on a heating plate to accelerate the curing of the polydimethylsiloxane; After the curing is completed, the polydimethylsiloxane film is peeled off to obtain a highly transparent super-hydrophobic film.
5. The method for preparing a super-hydrophobic surface based on laser-induced deep etching according to claim 1, characterized in that: The step 3. also includes: The etched glass mold is cleaned and dried, and a preheated soft polymethyl methacrylate substrate is placed on the glass mold; Apply pressure to the glass mold and substrate according to a preset pressure curve and continue for a certain period of time; After the polymethyl methacrylate substrate is cooled, it is peeled off to obtain a non-flexible high-transparency super-hydrophobic film.
6. A super hydrophobic surface film, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 5.
7. The super hydrophobic surface film according to claim 6, characterized in that: The diameter of the hole microstructure is less than 30 μm and the depth is greater than 60 μm.
8. The super hydrophobic surface film according to claim 6, characterized in that: Compared with smooth films, it can retain more than 95% transparency in the 300nm to 1100nm band.
9. A device for implementing the method of any one of claims 1 to 5 for producing a super-hydrophobic surface based on laser-induced deep etching, characterized in that: include: A laser emitting device configured to emit a pulse-shaped Bessel beam and perform a modification on the glass surface; Water bath heating equipment, used to etch and water bath heat the modified glass to form holes; A mold-turning material supply device configured to supply polydimethylsiloxane or polymethyl methacrylate for mold-turning processing; The film stripping device is used to strip the polydimethylsiloxane film or the polymethyl methacrylate film from the cured glass mold to obtain a super-hydrophobic surface.
10. The device of super-hydrophobic surface based on laser-induced deep etching according to claim 9, characterized in that: The laser emitting device comprises a laser, a beam expander collimator, a first reflector, a second reflector, a conical lens, a convex lens, a third reflector and a microscope objective lens which are sequentially placed along the laser output direction of the laser, and shapes the incident pulsed Gaussian beam to form a Bessel beam, and focuses the beam onto the glass surface through the convex lens and the microscope objective lens for modification.