Super-hydrophobic surface based on laser micromachining and UV transfer printing and preparation method thereof

Abstract

The invention discloses a super-hydrophobic surface based on laser micromachining and UV transfer printing and a preparation method thereof, and belongs to the field of material surface modification.The method comprises the steps that a microstructure template is machined on a high-purity metal nickel plate through picosecond or femtosecond laser, a microstructure is copied to the surface of a target base material with high precision through a circulating UV transfer printing technology, and the super-hydrophobic surface is obtained. Large-area splicing larger than 500 mm * 500 mm is achieved, finally, low-surface-energy nano particle dispersion liquid is sprayed, and a micro-nano graded rough structure is constructed after drying. The static water contact angle of the prepared super-hydrophobic surface is larger than or equal to 150 degrees, the rolling angle is smaller than or equal to 5 degrees, and the contact angle attenuation rate lt after the super-hydrophobic surface is abraded by 600 # abrasive paper 500 times; the coating has excellent mechanical durability, chemical stability and self-cleaning, anti-icing and anti-fouling functions, and is simple in process, low in cost and suitable for industrial large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of material surface modification, and specifically discloses a superhydrophobic surface based on laser micromachining and UV transfer printing and its preparation method. Background Technology

[0002] Superhydrophobic surfaces, as functional materials with special wettability, mimic the "self-cleaning" effect of organisms such as lotus leaves. They can automatically adsorb and remove surface contaminants as droplets roll off, thus showing great application potential in fields such as exterior wall coatings, solar panels, automotive glass, pipe anti-fouling, biofouling prevention, and aerospace anti-icing.

[0003] The core of achieving superhydrophobicity lies in constructing suitable micro-nano hierarchical rough structures and supplementing them with low surface energy material modification. Currently, there are many methods for preparing superhydrophobic surfaces, mainly including chemical vapor deposition, electrochemical deposition, sol-gel methods, etching methods, and template methods. Among these, the template method is considered one of the most promising technologies for large-scale production due to its ability to achieve high precision and controllable preparation of micron-level structures. However, existing superhydrophobic surface preparation methods based on the template replication principle still face many insurmountable bottlenecks: on the one hand, traditional templates are mostly prepared using chemical etching or photolithography, which is not only complex and costly, but also makes it difficult to balance the structural precision and durability of the template, making it unsuitable for large-area industrial production; on the other hand, most preparation methods rely only on single-scale microstructures or low surface energy modification, resulting in poor surface mechanical durability, and the superhydrophobic properties easily degrade rapidly after being subjected to external forces such as friction and impact. Currently, template methods mainly focus on using techniques such as soft etching and thermal embossing to replicate microstructures and achieve superhydrophobic properties. While these methods can indeed replicate structures with micron-level roughness to a certain extent, their inherent technical defects severely limit their application in industrial settings. Soft etching technology, represented by polydimethylsiloxane (PDMS), inevitably suffers fatigue aging, permanent deformation, and even structural damage during repeated use of its elastic templates, making it impossible to guarantee the consistency of product performance in mass production. Although thermal embossing technology can obtain structurally regular replicas, its process requires continuous high temperature and high pressure, which not only leads to high energy costs but also requires the processed substrate to have stronger heat resistance, making many common, inexpensive, or heat-sensitive polymer substrates (such as PVC) unsuitable. More importantly, the high temperature and high pressure process conditions easily cause thermal deformation of the polymer substrate and the rebound or collapse of the microstructure itself, making it difficult to achieve high-precision structural replication. Finally, while etching-based methods can directly fabricate microstructures on the substrate, the process causes irreversible damage to the substrate surface. Furthermore, the difficulty in precisely controlling the shape and precision of the structure during etching limits the ability to construct micro-nano hierarchical composite rough structures with high mechanical stability, resulting in limited improvements in hydrophobicity and durability. In addition, these methods may face technical challenges such as difficulty in process control and splicing when dealing with the need for large-area superhydrophobic surface fabrication.

[0004] The patent with publication number CN114100998A, "Method for preparing micro-nano structures on the surface of a substrate and substrate with micro-nano structures on the surface and its application", specifically discloses providing a micro-nano texture template, applying a transfer UV adhesive to the substrate and forming a transition adhesive layer with microstructures through UV transfer and curing, and then removing the adhesive layer by plasma etching and etching micro-nano structures on the surface of the substrate. However, the above scheme uses plasma etching to directly process microstructures on the substrate. This subtractive process may damage the surface integrity of the substrate and is limited by the type of substrate. Furthermore, there are challenges in constructing a stable micro-nano hierarchical composite rough structure on some substrates, which may affect the long-term stability of its surface mechanical durability and superhydrophobic properties. Summary of the Invention

[0005] To address the problems of poor durability, high energy consumption, and difficulty in balancing high precision and large-area production of existing superhydrophobic surfaces, this invention provides a superhydrophobic surface based on laser micromachining and UV transfer printing and its preparation method. The aim is to prepare a highly durable metal template by laser and combine it with cyclic UV transfer printing and nanoparticle modification technology to obtain a superhydrophobic functional surface with excellent mechanical durability, stable superhydrophobic properties, and the ability to be mass-produced industrially.

[0006] To achieve this objective, the following solution is provided: This invention provides a method for preparing a superhydrophobic surface based on laser micromachining and UV transfer printing, comprising the following steps: S1. A substrate template with a microstructure is formed on a clean and dry substrate template by laser micromachining. S2. The microstructure substrate template is bonded to the target substrate using UV-cured photoresist, and the microstructure is copied to the surface of the target substrate through a UV transfer process. S3. Repeatedly cycle the UV transfer process to form a large area of ​​microstructure on the surface of the target substrate; S4. The low surface energy nanoparticle dispersion is uniformly coated onto the surface of a large-area microstructure, and after drying, a large-area superhydrophobic surface is obtained.

[0007] Furthermore, in step S1, the substrate template is selected from high-purity nickel plates.

[0008] Further, in step S1, the microstructure is any one of papillary, grid-like, or pyramidal shapes; The papillae have a diameter of 10–12 μm, a height of 15–24 μm, and a depth-to-width ratio of 1.5–2.0. The line grid has a line width of 10~12 μm, a spacing of 20~25 μm, a height of 20~24 μm, and an aspect ratio of 2.0; The pyramid-shaped base is 15~20 μm in diameter, the height is 22.5~24 μm in height, and the aspect ratio is 1.5~2.0.

[0009] Furthermore, in step S1, the laser micromachining process uses a picosecond or femtosecond pulsed laser system; the laser power is 10~25 W, the temperature is 23℃, and the humidity is 35%.

[0010] Further, in step S2, UV-curable photoresist is coated onto the surface of the microstructure with a thickness of 50–100 μm and a coating speed of 5–10 mm / s; the pressure applied during bonding is 0.3–0.5 MPa, and the holding time is 5–10 s; during the UV transfer process, UV lamp irradiation is used for curing, with a wavelength of 365 nm and a power of 200–300 mW / cm². 2 The curing time is 5~10 s.

[0011] Furthermore, in step S2, the target substrate is acrylic, polycarbonate, polypropylene, or glass.

[0012] Further, in step S4, the low surface energy nanoparticles are hydrophobic nanoparticles with a particle size of 50~200 nm; preferably, they are one or more of polytetrafluoroethylene, silicon dioxide, titanium dioxide, zinc oxide, zirconium dioxide, aluminum oxide, and iron oxide.

[0013] Further, in step S4, the low surface energy nanoparticle dispersion uses ethanol as a solvent with a mass concentration of 0.5-2.0%; the spraying pressure of the low surface energy nanoparticle dispersion is 0.2-0.4 MPa, the spraying distance is 15-20 cm, and the coating thickness is 10-30 μm.

[0014] Furthermore, the laser micromachining process in step S1 must be performed within 2 hours after obtaining a clean and dry substrate template.

[0015] The present invention also provides a superhydrophobic surface based on laser micromachining and UV transfer prepared according to the above method.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention is the first to combine laser micromachining technology and UV transfer printing technology to prepare superhydrophobic surfaces. Firstly, based on picosecond or femtosecond pulsed laser micromachining of a nickel template, a micron-sized structure with smooth sidewalls and regular morphology can be precisely fabricated on a high-purity nickel plate, laying a solid foundation for subsequent high-fidelity UV transfer printing. Simultaneously, the nickel template possesses extremely high mechanical strength and durability, completely overcoming the defects of traditional PDMS soft templates, such as easy deformation, aging, and damage, and can withstand several cycles of UV transfer printing. After the microstructure is formed by laser processing, combined with a UV transfer process that can be performed at room temperature and pressure, the energy consumption is far lower than that of hot embossing, and it has good adaptability to various substrates such as acrylic, polycarbonate (PC), polypropylene (PP), and glass, avoiding damage to the target substrate and microstructure caused by high temperatures. Through precise cyclic UV transfer printing and splicing control, the limitations of traditional methods in terms of single-cycle preparation area are successfully overcome, enabling the stable and efficient preparation of surfaces exceeding 500... The large-area, seamless microstructured surface of 500 mm × 100 mm provides a technological guarantee for the large-scale application of superhydrophobic surfaces. Furthermore, this invention successfully constructed a stable micro-nano hierarchical rough structure by spraying hydrophobic nanoparticles of specific particle size and concentration onto the large-area microstructure obtained by UV transfer. This dual-roughness microstructure effectively prevents direct contact between solid water droplets and the substrate surface, thereby stably achieving a superhydrophobic state. The surface static water contact angle is stable at ≥150°, and the roll-off angle is ≤5°, resulting in extremely excellent superhydrophobic performance.

[0017] 2. This invention utilizes a high-precision laser micromachining template to ensure the accuracy and durability of the original structure, providing a reliable replication source for cyclic UV transfer printing. Cyclic UV transfer printing successfully replicates the microstructure onto a large-area substrate, breaking through the limitation of single-batch fabrication area. The optimized nanoparticle coating, combined with the replicated microstructure, forms a robust micro-nano composite interface. These three elements are interconnected, producing a significant synergistic gain effect. The resulting superhydrophobic surface not only has a large static water contact angle and a small roll-off angle but also possesses excellent mechanical durability. After 500 cycles of heavy abrasion with 600# sandpaper, its contact angle attenuation rate can be controlled within 8%, far superior to most existing superhydrophobic surfaces. This comprehensive advantage, combining excellent superhydrophobicity, high mechanical durability, large-area fabrication capability, and good substrate versatility, effectively solves the long-standing bottleneck restricting the practical application of superhydrophobic surfaces, giving them broad application prospects in harsh environments such as bathroom fixtures, automobiles, construction, and shipbuilding. Attached Figure Description

[0018] Figure 1 This is a 3D microscopic morphology image of the laser-engraved microstructure substrate template in Embodiment 1 of the present invention; Figure 2This is a SEM image of the superhydrophobic acrylic surface based on laser micromachining and UV transfer in Embodiment 1 of the present invention. Figure 3 This is an image of the static water contact angle (CA) of the acrylic superhydrophobic surface based on laser micromachining and UV transfer in Embodiment 1 of the present invention. Figure 4 The image shows the change in contact angle of the superhydrophobic acrylic surface based on laser micromachining and UV transfer after 500 sandpaper rubbings in Embodiment 1 of the present invention. Figure 5 The image shows the static water contact angle (CA) of the PC superhydrophobic surface based on laser micromachining and UV transfer in Embodiment 2 of the present invention. Figure 6 This is an image of the static water contact angle (CA) of the glass superhydrophobic surface based on laser micromachining and UV transfer in Embodiment 3 of the present invention. Figure 7 This is an image of the static water contact angle (CA) of the PP superhydrophobic surface based on laser micromachining and UV transfer in Embodiment 4 of the present invention; Figure 8 This is an image of the static water contact angle (CA) of the PC superhydrophobic surface based on laser micromachining and UV transfer in Embodiment 5 of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to preferred embodiments. The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values. These ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein.

[0020] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0021] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0022] Example 1 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned at 200 W for 20 min. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a femtosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A grid array scanning path and a scanning speed of 500 mm / s were set to process a papillary pattern with a diameter of 10 μm, a height of 15 μm, and an aspect ratio of 1.5. The parameters were orthogonally optimized in an environment with a temperature of 23℃, a humidity of 35%, and a Class 1000 environment. Finally, a laser power of 15 W and a scanning area of ​​20 mm × 20 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was monitored in real time using a laser confocal microscope to ensure that it was ≤0.5 μm. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 5 mm / s and a coating thickness of 50 μm. After bonding the acrylic substrate to the UV adhesive layer, a pressure of 0.3 MPa is applied and held for 10 s. The wavelength is 365 nm and the power is 200 mW / cm². 2 After curing under a UV lamp for 10 seconds, the acrylic substrate surface was separated to replicate the papillary microstructure. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructure acrylic surface of 550 mm × 550 mm. S4. Select hydrophobic silica nanoparticles with a particle size of 50 nm, use ethanol as solvent to prepare a dispersion with a mass concentration of 0.5%, ultrasonically disperse for 30 min, and uniformly coat the dispersion onto the large-area microstructured acrylic surface using a spraying method. The spraying pressure is 0.2 MPa, the spraying distance is 15 cm, and the coating thickness is 10 μm. After coating, place the sample in a vacuum drying oven to dry, and obtain a large-area superhydrophobic surface.

[0023] The microstructured substrate template prepared in this embodiment was observed using a laser co-concentration microscope, and its three-dimensional morphology is as follows: Figure 1 As shown, the array of papillary microstructures is highly uniform and consistent. The morphology of the final superhydrophobic surface was observed using scanning electron microscopy (SEM), as shown in the figure. Figure 2 As shown, it can be clearly observed that a complete papillary microstructure has been successfully replicated on the acrylic substrate surface. Performance tests were performed on the large-area superhydrophobic surface prepared in this embodiment, and the results are as follows: Figure 3 As shown, the static water contact angle of different regions of this superhydrophobic surface is 162° and the roll-off angle is 3°; Figure 4 As shown, after 500 cycles of heavy abrasion with 600# sandpaper, the static water contact angle is 152°, and the contact angle attenuation rate is 6.2%.

[0024] Example 2 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned for 18 min with a power of 250 W. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a picosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A linear array scanning path and a scanning speed of 800 mm / s were set to process a grid pattern with a line width of 10 μm, a spacing of 20 μm, a height of 20 μm, and an aspect ratio of 2.0. The parameters were orthogonally optimized in an environment with a temperature of 23℃, a humidity of 35%, and a Class 1000 environment. Finally, a laser power of 20 W and a scanning area of ​​20 mm × 20 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was ensured to be ≤0.5 μm by real-time monitoring using a laser confocal microscope. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 8 mm / s and a coating thickness of 80 μm. After bonding the PC substrate to the UV adhesive layer, a pressure of 0.4 MPa is applied and held for 8 s. The wavelength is 365 nm and the power is 250 mW / cm². 2 After curing under UV light for 8 seconds, the substrate is separated to replicate a grid-like microstructure on the PC substrate surface. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructured PC surface of 600 mm × 500 mm. S4. Hydrophobic PTFE nanoparticles with a particle size of 100 nm were selected, and a dispersion with a mass concentration of 1.0% was prepared using ethanol as a solvent. The dispersion was ultrasonically dispersed for 30 min, and the dispersion was uniformly coated onto the large-area microstructured PC surface using a spraying method. The spraying pressure was 0.3 MPa, the spraying distance was 18 cm, and the coating thickness was 20 μm. After coating, the sample was placed in a vacuum drying oven to dry, resulting in a large-area superhydrophobic surface.

[0025] The performance of the large-area superhydrophobic surface prepared in this embodiment was tested, and its specific morphology is shown in the figure below. Figure 5As shown, the static water contact angle of different areas of the surface is 160° and the roll-off angle is 3°. After being abraded with 600# sandpaper 500 times, the static water contact angle of this hydrophobic surface is 154°.

[0026] Example 3 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned at 300 W for 15 min. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a picosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A triangular array scanning path and a scanning speed of 1000 mm / s were set to process a pyramid-shaped pattern with a base of 15 μm, a height of 22.5 μm, and an aspect ratio of 1.5. The parameters were orthogonally optimized in an environment with a temperature of 23℃, humidity of 35%, and Class 1000. Finally, a laser power of 25 W and a scanning area of ​​30 mm × 30 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was ensured to be ≤0.5 μm by real-time monitoring using a laser confocal microscope. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a speed of 10 mm / s and a coating thickness of 100 μm. After bonding the glass substrate to the UV adhesive layer, a pressure of 0.5 MPa is applied and held for 5 s. The wavelength is 365 nm and the power is 300 mW / cm². 2 After curing with a UV lamp for 5 seconds, the glass substrate was separated to replicate a pyramid-shaped microstructure on its surface. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructured glass surface of 600 mm × 600 mm. S4. Select hydrophobic zinc oxide nanoparticles with a particle size of 200 nm, use ethanol as solvent to prepare a dispersion with a mass concentration of 2.0%, ultrasonically disperse for 30 min, and uniformly coat the dispersion onto the large-area microstructured glass surface using a spraying method. The spraying pressure is 0.4 MPa, the spraying distance is 20 cm, and the coating thickness is 30 μm. After coating, place the sample in a vacuum drying oven to dry, and obtain a large-area superhydrophobic surface.

[0027] The performance of the large-area superhydrophobic surface prepared in this embodiment was tested, and its specific morphology is shown in the figure below. Figure 6As shown, the static water contact angle of different areas of the surface is 161° and the roll-off angle is 4°. After the hydrophobic surface is abraded 500 times with 600# sandpaper, the static water contact angle is 151°.

[0028] Example 4 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned at 280 W for 16 min. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a picosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A grid array scanning path and a scanning speed of 700 mm / s were set to process a papillary pattern with a diameter of 12 μm, a height of 24 μm, and an aspect ratio of 2.0. The parameters were orthogonally optimized in an environment with a temperature of 23℃, humidity of 35%, and Class 1000. Finally, a laser power of 10 W and a scanning area of ​​25 mm × 25 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was ensured to be ≤0.5 μm by real-time monitoring using a laser confocal microscope. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 9 mm / s and a coating thickness of 90 μm. After bonding the PP substrate to the UV adhesive layer, a pressure of 0.5 MPa is applied and held for 6 s. The wavelength is 365 nm and the power is 280 mW / cm². 2 After curing under UV light for 6 seconds, the substrate is separated to replicate a pyramid-shaped microstructure on the surface of the PP substrate. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructure PP surface of 500 mm × 600 mm. S4. Select hydrophobic silica nanoparticles with a particle size of 200 nm, use ethanol as solvent to prepare a dispersion with a mass concentration of 1.2%, ultrasonically disperse for 30 min, and uniformly coat the dispersion onto the large-area microstructure PP surface using a spraying method. The spraying pressure is 0.35 MPa, the spraying distance is 19 cm, and the coating thickness is 22 μm. After coating, place the sample in a vacuum drying oven to dry, and obtain a large-area superhydrophobic surface.

[0029] The performance of the large-area superhydrophobic surface prepared in this embodiment was tested, and its specific morphology is shown in the figure below. Figure 7As shown, the static water contact angle of different areas of the surface is 158° and the roll-off angle is 3°. After the hydrophobic surface is abraded 500 times with 600# sandpaper, the static water contact angle is 153°.

[0030] Example 5 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned at 220 W for 19 min. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a picosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A linear array scanning path and a scanning speed of 900 mm / s were set to process a grid pattern with a line width of 12 μm, a spacing of 25 μm, a height of 24 μm, and an aspect ratio of 2.0. The parameters were orthogonally optimized in an environment with a temperature of 23℃, a humidity of 35%, and a Class 1000 environment. Finally, a laser power of 25 W and a scanning area of ​​25 mm × 25 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was ensured to be ≤0.5 μm by real-time monitoring using a laser confocal microscope. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 9 mm / s and a coating thickness of 90 μm. After bonding the PC substrate to the UV adhesive layer, a pressure of 0.5 MPa is applied and held for 6 s. The wavelength is 365 nm and the power is 280 mW / cm². 2 After curing with a UV lamp for 6 seconds, the substrate is separated to replicate a grid-like microstructure on the PC substrate surface. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructured PC surface of 500 mm × 600 mm. S4. Hydrophobic alumina nanoparticles with a particle size of 100 nm were selected. A dispersion with a mass concentration of 1.2% was prepared using ethanol as a solvent. The dispersion was ultrasonically dispersed for 30 min. The dispersion was then uniformly coated onto the large-area microstructure PC surface using a spraying method. The spraying pressure was 0.35 MPa, the spraying distance was 19 cm, and the coating thickness was 22 μm. After coating, the sample was dried in a vacuum drying oven to obtain a large-area superhydrophobic surface.

[0031] The performance of the large-area superhydrophobic surface prepared in this embodiment was tested, and its specific morphology is shown in the figure below. Figure 8As shown, the static water contact angle of different areas of the surface is 157° and the roll-off angle is 5°. After the hydrophobic surface is abraded 500 times with 600# sandpaper, the static water contact angle is 150°.

[0032] Example 6 The method for preparing superhydrophobic surfaces based on laser micromachining and UV transfer includes the following steps: S1. A 99.9% pure nickel plate was selected as the substrate template. The substrate template was placed in analytical grade anhydrous ethanol and ultrasonically cleaned at 200 W for 20 min. It was then dried by low-temperature nitrogen purging to obtain a clean and dry substrate template. Within 2 h, a femtosecond pulsed laser micromachining system was used. The laser was transmitted to the scanning galvanometer via a reflector, focused, and positioned on the clean and dry substrate template. A triangular array scanning path and a scanning speed of 500 mm / s were set to process a pyramid-shaped pattern with a base of 20 μm, a height of 24 μm, and an aspect ratio of 2.0. The parameters were orthogonally optimized in an environment with a temperature of 23℃, humidity of 35%, and Class 1000. Finally, a laser power of 15 W and a scanning area of ​​20 mm × 20 mm were used to process and form a microstructure substrate template. The surface flatness error of the processed microstructure substrate template was ensured to be ≤0.5 μm by real-time monitoring using a laser confocal microscope. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 5 mm / s and a coating thickness of 50 μm. After bonding the acrylic substrate to the UV adhesive layer, a pressure of 0.3 MPa is applied and held for 10 s. The wavelength is 365 nm and the power is 200 mW / cm². 2 After curing under a UV lamp for 10 seconds, the acrylic substrate surface was separated to replicate the papillary microstructure. S3. Repeat the above UV transfer process, and control the splicing error of adjacent areas within ±0.1 mm to finally obtain a large area microstructure acrylic surface of 550 mm × 550 mm. S4. Hydrophobic zirconium dioxide nanoparticles with a particle size of 200 nm and hydrophobic iron oxide nanoparticles with a particle size of 200 nm were selected and mixed with ethanol as solvent to prepare a dispersion with a mass concentration of 0.5%. The dispersion was ultrasonically dispersed for 30 min. The dispersion was uniformly coated onto the large-area microstructured acrylic surface by spraying. The spraying pressure was 0.2 MPa, the spraying distance was 15 cm, and the coating thickness was 10 μm. After coating, the sample was placed in a vacuum drying oven to dry, thus obtaining a large-area superhydrophobic surface.

[0033] The performance of the large-area superhydrophobic surface prepared in this embodiment was tested, and its specific morphology is shown in the figure below. Figure 8As shown, the static water contact angle of different areas of the surface is 155° and the roll-off angle is 4°. After being abraded with 600# sandpaper 500 times, the static water contact angle of this hydrophobic surface is 150°.

[0034] Comparative Example 1 This comparative example provides a method for preparing a superhydrophobic surface, including the following steps: S1. Using a silicon wafer as the substrate, a wire grid microstructure template is prepared by conventional etching processes of coating, exposure, and development. The wire grid has a line width of 10 μm, a spacing of 20 μm, and a height of 20 μm. Hydrofluoric acid solution is required for the etching process, and the process takes 8 hours. S2. UV-curable photoresist is coated onto the surface of the microstructure substrate template using a blade coating method at a coating speed of 8 mm / s and a coating thickness of 80 μm. After bonding the PC substrate to the UV adhesive layer, a pressure of 0.4 MPa is applied and held for 8 s. The wavelength is 365 nm and the power is 250 mW / cm². 2 After curing under UV light for 8 seconds, the substrate is separated to replicate the microstructure on the PC substrate surface. The UV transfer process is repeated to finally obtain a large-area microstructure PC surface of 500 mm × 500 mm. S3. Hydrophobic PTFE nanoparticles with a particle size of 100 nm were selected. A dispersion with a mass concentration of 1.0% was prepared using ethanol as a solvent. The dispersion was ultrasonically dispersed for 30 min. The dispersion was then uniformly coated onto the large-area microstructured PC surface using a spraying method. The spraying pressure was 0.3 MPa, the spraying distance was 18 cm, and the coating thickness was 20 μm. After coating, the sample was dried in a vacuum drying oven to obtain a large-area superhydrophobic surface.

[0035] The performance of the large-area superhydrophobic surface prepared in this comparative example was tested. The static water contact angle of this hydrophobic surface was 158° and the roll-off angle was 4°. After 500 abrasions with 600# sandpaper, the contact angle dropped to 140°~142°. This loss was much higher than that of the superhydrophobic surface of this invention after abrasion. This indicates that the microstructure replicated by the traditional photolithography template has insufficient stability or bonding strength with nanoparticles, resulting in poor wear resistance. At the same time, the template preparation time of this comparative example is 6 times that of this invention, and the use of hydrofluoric acid etching also has environmental pollution problems.

[0036] Comparative Example 2 This comparative example provides a method for preparing a superhydrophobic surface, including the following steps: The difference from Example 2 is that step S4 does not use nanoparticle coating and post-treatment. Instead, fluorosilane vapor is used to directly modify the large-area microstructured PC surface obtained in step S3. The treatment temperature is 80°C and the time is 30 min to obtain a large-area superhydrophobic surface.

[0037] The performance of the large-area superhydrophobic surface prepared in this comparative example was tested. The static water contact angle of the hydrophobic surface was 135° and the roll-off angle was 15°. This proves that the surface failed to meet the superhydrophobic standard (≥150°) and had poor self-cleaning performance, with water droplets unable to remove dust. After being abraded 200 times with 600# sandpaper, the contact angle dropped to 120°, and the durability was far lower than that of the superhydrophobic surface prepared in this invention.

[0038] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for fabricating superhydrophobic surfaces based on laser micromachining and UV transfer, characterized in that, The method comprises the following steps: S1, forming a substrate template with microstructure on a clean and dry substrate template by laser microprocessing treatment; S2, adhering the microstructure substrate template to a target substrate through UV curing photoresist, and copying the microstructure to the surface of the target substrate through UV transfer process; S3, repeatedly circulating the UV transfer process to form a large-area microstructure on the surface of the target substrate; S4, uniformly coating a low surface energy nanoparticle dispersion liquid on the surface of the large-area microstructure, and obtaining a large-area super-hydrophobic surface after drying.

2. The method according to claim 1, wherein, In step S1, the substrate template is selected from high-purity nickel plates.

3. The method according to claim 1, wherein, In step S1, the microstructure is any one of papillary, line grid or pyramid; The papillary has a diameter of 10-12 μm, a height of 15-24 μm, and an aspect ratio of 1.5-2.0; The line grid has a line width of 10-12 μm, a pitch of 20-25 μm, and a height of 20-24 μm, and an aspect ratio of 2.0; The pyramid has a bottom edge of 15-20 μm, a height of 22.5-24 μm, and an aspect ratio of 1.5-2.

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4. The method according to claim 1, wherein, In step S1, the laser microprocessing treatment adopts a picosecond or femtosecond pulsed laser system; the laser power is 10-25 W, the temperature is 23℃, and the humidity is 35%.

5. The method according to claim 1, wherein, In step S2, the UV curing photoresist is coated on the microstructure surface, the coating thickness is 50-100 μm, the coating speed is 5-10 mm / s; the pressure applied during lamination is 0.3-0.5 MPa, and the holding time is 5-10 s; during the UV transfer process, UV lamp irradiation curing is adopted, the wavelength of the UV lamp is 365 nm, the power is 200-300 mW / cm 2 , and the curing time is 5-10 s.

6. The method according to claim 1, wherein, In step S2, the target substrate is acrylic, polycarbonate, polypropylene or glass.

7. The method according to claim 1, wherein, In step S4, the low surface energy nanoparticles are hydrophobic nanoparticles with a particle size of 50-200 nm; preferably one or more of polytetrafluoroethylene, silicon dioxide, titanium dioxide, zinc oxide, zirconium dioxide, aluminum oxide, and iron oxide.

8. The method according to claim 1, wherein, In step S4, the low surface energy nanoparticle dispersion liquid uses ethanol as the solvent, and the mass concentration is 0.5-2.0%; the spraying pressure of the low surface energy nanoparticle dispersion liquid is 0.2-0.4 MPa, the spraying distance is 15-20 cm, and the coating thickness is 10-30 μm.

9. The method according to claim 1, wherein, The laser microprocessing treatment in step S1 needs to be performed within 2 hours after obtaining the clean and dry substrate template.

10. A super-hydrophobic surface based on laser microprocessing and UV transfer prepared by any of the preparation methods of claims 1-9.

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