A method for preparing a high-precision microstructure coating
By combining magnetic field effects with wax solution, the problem of preparing high-precision microstructure coatings has been solved, enabling low-cost and high-efficiency coating production. The coatings possess superhydrophobic and superlubricating properties, making them suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGSHU INSTITUTE OF TECHNOLOGY
- Filing Date
- 2024-06-14
- Publication Date
- 2026-06-05
Smart Images
Figure BDA0004892932440000041
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coating preparation, and relates to a method for preparing a high-precision microstructure coating, and more particularly to a method for preparing a superhydrophobic coating with a high-precision microstructure. Background Technology
[0002] Superhydrophobic coatings have attracted widespread attention in fields such as oil-water separation, lubrication and drag reduction, directional transport, microfluidics, antifouling, and de-icing due to their unique surface properties. To achieve superhydrophobic properties, coatings typically require rough microstructures and low surface energy materials. With continuous technological advancements, randomly distributed rough microstructures are increasingly insufficient to meet ever-higher demands. For example, tiny oil droplets in oil-water separation require even smaller structures for effective separation, and directional transport surfaces and microfluidic surfaces often require precisely designed, periodically arranged microstructures to achieve their functions. To obtain these high-precision microstructures, methods such as femtosecond laser etching, photolithography, and 3D printing are commonly used. These methods are expensive, costly, or have low processing efficiency, making them unsuitable for mass production. While template methods are low-cost and suitable for mass production, the small size of the microstructures increases the influence of surface tension, making it extremely difficult to wet the recessed microstructures on the template with the precursor fluid. Furthermore, the microstructures are easily damaged during coating curing and demolding. Using release agents increases costs and production processes, and the release agents themselves also struggle to wet the microstructures on the template. Summary of the Invention
[0003] Purpose of the invention: The purpose of this invention is to provide a method for preparing a high-precision microstructure coating. By using a magnetic field, the precursor fluid can be completely wetted and filled into the microstructure. The addition of wax allows for easy demolding without the need for a release agent. The resulting coating has a complete microstructure and high precision.
[0004] Technical solution: The present invention provides a method for preparing a high-precision microstructure coating, comprising the following steps:
[0005] S1. Template preparation: A template containing microstructures is prepared using HTL high-temperature resistant photosensitive resin material with a photopolymerization 3D printer and cleaned with anhydrous ethanol and deionized water.
[0006] S2. Preparation of precursor solution: The precursor solution is obtained by adding a solution composed of film-forming substances to magnetic nanoparticles and wax solution and mixing them evenly.
[0007] S3. Preparation of microstructure coating: Pour the precursor liquid prepared in S2 into the template, place the entire device in a magnetic field, let it stand and solidify, and peel off the template to obtain a hydrophobic coating with high-precision microstructure.
[0008] Furthermore, step S2 specifically includes the following steps:
[0009] S201. Mix and stir polydimethylsiloxane and curing agent, then add Fe3O4 magnetic nanoparticles to the above mixed solution as component A;
[0010] S202. Add wax to a wax solution solvent, heat and stir until homogeneous. The resulting wax solution is component B.
[0011] S203. Mix components A and B, heat and stir until homogeneous to obtain a precursor fluid.
[0012] Furthermore, the microstructure in step S1 is a porous inverted conical structure.
[0013] Furthermore, the mass ratio of the polydimethylsiloxane to the curing agent is (8-12):1.
[0014] Furthermore, the mass ratio of the Fe3O4 magnetic nanoparticles to polydimethylsiloxane is (0.25–1.25):1.
[0015] Further, the mass ratio of the wax to the wax solution solvent is (0.001-0.015):1; the mass ratio of the wax solution solvent to polydimethylsiloxane is (0.25-1.25):1.
[0016] Furthermore, the wax is a mixture of carnauba wax and substance A, wherein substance A is one or a mixture of two of microcrystalline wax and beeswax, and the mass ratio of carnauba wax to substance A is (0.5-1.5):1.
[0017] Furthermore, the solvent for the wax solution is one of anhydrous ethanol, chloroform, and toluene.
[0018] Furthermore, the strength of the magnetic field described in S3 is 0.2–0.8 T, and the resting time is 30–60 min.
[0019] Furthermore, the curing described in S3 is performed using one of the following methods: infrared lamp curing, oven curing, or natural air drying curing.
[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) By using a magnetic field, the precursor fluid is completely wetted into the microstructure on the template, and a coating with high-precision microstructure can be obtained after molding. The preparation method proposed in this invention is also applicable to the preparation of coatings with microstructures of other shapes, and is also applicable to obtaining high-precision microstructures from other polymer materials.
[0021] (2) The addition of carnauba wax causes the coating to precipitate a rose-like structure during the curing process, increasing the surface roughness of the coating. No further processing is required, and the coating already possesses superhydrophobic properties. The addition of microcrystalline wax and beeswax provides the low surface energy material necessary for superhydrophobicity and also gives the coating super-slippery properties, allowing for easy demolding of the microstructure without the need for a release agent.
[0022] (3) Under the combined action of template, magnetic field and wax, microstructures that are difficult to mass-produce at low cost by other methods can be obtained, and the coated microstructures have high dimensional accuracy and structural integrity. This method has a simple manufacturing process, controllable cost, and is suitable for large-scale production. Detailed Implementation
[0023] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0024] Example 1:
[0025] S1. Template preparation: A template composed of a porous structure was prepared using HTL high-temperature resistant photosensitive resin material with a photopolymerization 3D printer. The porous structure has an inverted conical shape with a diameter of 50μm and a height of 150μm. The substrate was cleaned with anhydrous ethanol and deionized water.
[0026] S2. Preparation of the precursor solution: Mix 100g of polydimethylsiloxane and curing agent at a mass ratio of 10:1 and stir. Then add 50g of Fe3O4 magnetic nanoparticles to the above mixture as component A. Mix 0.1g of carnauba wax, 0.05g of microcrystalline wax and 0.05g of beeswax in 100g of anhydrous ethanol, heat to 70℃ and stir until homogeneous. The resulting wax solution is component B. Stir components A and B together at 70℃ to obtain the precursor solution.
[0027] S3. Preparation of Microstructured Coating: The precursor liquid prepared in S2 is poured into the template, and the entire apparatus is placed in a 0.5T magnetic field. After standing for 30 minutes, it is cured by irradiation with an infrared lamp. The template is then peeled off to obtain a hydrophobic coating with a high-precision microstructure.
[0028] The specific data on the amount of carnauba wax, microcrystalline wax, beeswax, and anhydrous ethanol added in Examples 1-7 and Comparative Examples 1-3 are shown in Table 1:
[0029] Table 1:
[0030] diameter high Brazilian carnauba wax Microcrystalline wax beeswax Anhydrous ethanol Contact angle Example 1 50 150 0.1 0.05 0.05 100 107 Example 2 100 300 0.2 0.1 0.1 100 121 Example 3 300 1000 0.3 0.15 0.15 100 156 Example 4 1000 3000 0.6 0.3 0.3 100 155 Comparative Example 1 300 1000 No addition 0.15 0.15 100 105 Comparative Example 2 300 1000 0.3 No addition No addition 100 135 Comparative Example 3 300 1000 0.9 0.45 0.45 100 156 Example 5 2000 6000 0.075 0.0375 0.0375 25 109 Example 6 3000 9000 0.15 0.075 0.0.75 50 126 Example 7 5000 15000 0.375 0.1875 0.1875 125 154 Comparative Example 4 300 1000 0.3 0.15 0.15 100 135
[0031] The contact angle refers to the angle between the tangent at the gas-liquid interface at the gas-liquid-solid three-phase junction and the liquid-solid interface. When the contact angle is greater than 90°, the coating exhibits hydrophobic properties. The larger the contact angle, the higher the hydrophobic effect. When the contact angle is greater than 150°, it is considered superhydrophobic. Examples 1-4 in Table 1 all achieved smooth demolding of the coating, intact microstructure shape, and no obvious defects, meeting the requirements for preparing high-precision microstructure coatings. Furthermore, it can be seen that the contact angle increases with the gradual increase in the amount of carnauba wax and the corresponding amounts of microcrystalline wax and beeswax.
[0032] In Comparative Example 1, without the addition of carnauba wax, although the coating was successfully demolded and the microstructure was intact without obvious defects, the contact angle was only 105°. In Comparative Example 2, without the addition of microcrystalline wax and beeswax, the self-lubricating ability was lost, and the demolding was difficult, resulting in damage to the microstructure and causing most of the microstructure to be incomplete.
[0033] In Comparative Example 3, the mass ratio of wax to wax solution solvent was 0.018:1. The high wax content resulted in incomplete dissolution, but it did not affect the water contact angle of the coating. The coating was successfully demolded, and the microstructure remained intact without any obvious defects. White wax particles remained on the surface of the microstructure.
[0034] Examples 5-7 show that, while maintaining the constant ratio of wax to wax solution solvent, the ratio of wax solution solvent to polydimethylsiloxane was adjusted, resulting in coating contact angles of 109°, 126°, and 154°, respectively. Therefore, the more wax solution solvent and the corresponding amount of wax added, the larger the contact angle. Furthermore, these examples all achieved smooth coating demolding, intact microstructure shape, and no obvious defects, meeting the requirements for preparing high-precision microstructure coatings.
[0035] Comparative Example 4 had the same component content as Example 3, but no magnetic field was applied. This did not affect the demolding of the coating, but it resulted in most of the microstructures being missing or incomplete. This shows that applying a magnetic field is essential for preparing microstructures and improving precision.
[0036] Examples 8-10:
[0037] S1. Template preparation: A template composed of a porous structure was prepared using HTL high-temperature resistant photosensitive resin material with a photopolymerization 3D printer. The porous structure has an inverted conical shape with a diameter of 300 μm and a height of 1000 μm. The substrate was cleaned with anhydrous ethanol and deionized water.
[0038] S2. Preparation of the precursor solution: Mix 100g of polydimethylsiloxane and curing agent at a mass ratio of 10:1 and stir. Then add Fe3O4 magnetic nanoparticles to the above mixture as component A. Mix 0.3g of carnauba wax, 0.15g of microcrystalline wax and 0.15g of beeswax in 100g of anhydrous ethanol, heat to 70℃ and stir until homogeneous. The resulting wax solution is component B. Stir components A and B together at 70℃ to obtain the precursor solution.
[0039] S3. Preparation of Microstructured Coating: The precursor liquid prepared in S2 was poured into the template, and the entire apparatus was placed in a magnetic field. After standing for 30 minutes, it was cured by infrared lamp irradiation. The template was then peeled off to obtain a hydrophobic coating with a high-precision microstructure. The amount of Fe3O4 magnetic nanoparticles added and the applied magnetic field strength are shown in Table 2, Examples 8-10.
[0040] Table 2:
[0041]
[0042] Table 2 shows the effects of the mass ratio of Fe3O4 magnetic nanoparticles to polydimethylsiloxane and the applied magnetic field strength on the coating performance in Examples 8-10. Excessive addition of Fe3O4 magnetic nanoparticles leads to particle agglomeration and large structure sizes. Therefore, when a template is present, some template is not completely filled, resulting in some microstructure defects and some microstructures not forming. Insufficient addition of Fe3O4 magnetic nanoparticles prevents the formation of microstructures. Similarly, insufficient applied magnetic field results in incomplete filling of the template microstructure, leading to some microstructure defects. Therefore, only when a sufficient magnetic field strength is applied and the amount of Fe3O4 magnetic nanoparticles is appropriate can the prepared coating achieve a complete microstructure.
[0043] As can be seen from Examples 8-10, when the mass ratio of Fe3O4 magnetic nanoparticles to polydimethylsiloxane is (0.25-1.25):1 and the applied magnetic field strength is 0.2-0.8T, a hydrophobic coating with a complete microstructure can be prepared without affecting the contact angle.
Claims
1. A method for preparing a high-precision microstructure coating, characterized in that, Includes the following steps: S1. Template preparation: A template containing microstructures is prepared using HTL high-temperature resistant photosensitive resin material with a photopolymerization 3D printer and cleaned with anhydrous ethanol and deionized water. S2. Preparation of precursor solution: The precursor solution is obtained by adding a solution composed of film-forming substances to magnetic nanoparticles and wax solution and mixing them evenly. S3. Preparation of microstructure coating: Pour the precursor liquid prepared in S2 into the template, place the whole device in a magnetic field, let it stand and solidify, and peel off the template to obtain a hydrophobic coating with high-precision microstructure. Step S2 specifically includes the following steps: S201. Mix and stir polydimethylsiloxane and curing agent, then add Fe3O4 magnetic nanoparticles to the above mixed solution as component A; S202. Add wax to the wax solution solvent, heat and stir until homogeneous. The prepared wax solution is component B. S203. Mix components A and B, heat and stir until homogeneous to obtain a precursor fluid; The mass ratio of Fe3O4 magnetic nanoparticles to polydimethylsiloxane is (0.25~1.25):1; the wax is a mixture of carnauba wax and substance A, wherein substance A is microcrystalline wax and beeswax; the strength of the magnetic field in S3 is 0.2~0.8 T.
2. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The microstructure in step S1 is a porous inverted conical structure.
3. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The mass ratio of polydimethylsiloxane to curing agent is (8~12):
1.
4. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The mass ratio of the wax to the wax solution solvent is (0.001~0.015):1; the mass ratio of the wax solution solvent to polydimethylsiloxane is (0.25~1.25):
1.
5. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The mass ratio of carnauba wax to substance A is (0.5~1.5):
1.
6. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The solvent for the wax solution is one of anhydrous ethanol, chloroform, or toluene.
7. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, In S3, the settling time is 30~60 minutes.
8. The method for preparing a high-precision microstructure coating according to claim 1, characterized in that, The curing process described in S3 employs one of the following methods: infrared lamp curing, oven curing, or natural air drying curing.