基于飞秒激光和自组装技术提高树脂涂层疏水性的工艺

Improvement Process of Resin Coating Hydrophobicity Based on Femtosecond Laser and Self-assembly Technology

目的针对超疏水涂料功能持久性差的问题,提出一种将飞秒激光加工技术与微球近场效应原理相结合在氟化有机硅树脂表面制备微纳米仿生结构的解决方案。方法模仿蝴蝶翅膀鳞片微结构特征,以平滑的氟化有机硅树脂表面为基体,采用纳米自组装技术在其表面生长一层二氧化硅微球薄膜,然后设置飞秒激光器的参数,利用激光脉冲能量加工单层二氧化硅微球薄膜,二氧化硅微球颗粒对激光能量有进一步的聚焦加强作用,可以加工微纳米尺寸的结构。重点研究激光功率和扫描速度等参量对氟硅树脂图案形貌及疏水性的影响,并对比分析超疏水涂料和仿生微纳米表面的疏水功能持久性。结果激光扫描速度和功率参量对仿生表面疏水性能的影响较大,在激光功率为9 mW、扫描速度为10 mm/s、加工间距为10μm时可以获得最佳疏水性能,其接触角达到150°以上,通过常用的摩擦磨损测试实验,对比分析实验结果发现,氟硅树脂层经历200~1000次摩擦后,其接触角(CA)的下降幅度低于传统涂料组,说明具有仿生纳米坑结构的表面的耐磨性更强。结论利用飞秒激光加工的纳米微孔阵列结构可以明显提高氟硅树脂的疏水特性,并具有优异的持久性。

The surface structure of traditional superhydrophobic coatings is composed of a series of micro-nano structure bumps.Long-term friction will make the bumps smooth or even fail,which is the reason for the poor durability of traditional superhydrophobic coatings.How to balance the durability and hydrophobicity is the most important thing in the current research.Insects such as butterflies and moths can fly in the rain in nature,and the insect wings have very good hydrophobic characteristics.Inspired by this,through imitation of the surface structure of butterfly wings in nature,a processing technology combining femtosecond laser with the principle of near-field effect of microspheres was proposed to prepare micro/nano biomimetic structures on the surface of fluorinated silicone resin.When the laser pulse was applied to the silica microspheres,the energy was further concentrated and enhanced due to the near-field effect,resulting in a microporous pattern on the surface of the resin layer.This surface structure mimiced the surface structure of the butterfly wing and achieved air locking,which could lift the droplets more effectively and achieve the effect of superhydrophobicity.To imitate the scale and microstructure characteristics of butterfly wings,a thin film of silica microspheres was grown on the surface of a smooth fluorinated silicone resin with a certain hydrophobic property by the tensile method,and then a femtosecond laser was used to scan the surface of the film,so as to produce a densely arranged nanopore structure.In the experiment,the parameters such as laser power and scanning speed were mainly studied to explore the morphology and hydrophobicity,and the hydrophobic functional durability of the superhydrophobic coating and the bionic micro/nano surface was compared and analyzed.The self-assembly technology can be used to quickly fabricate large-area monolayer microsphere films,while the femtosecond laser has highly controllable parameters,concentrated energy,and the processing technology is very mature,which is an ideal tool for possibility of droplet immersion into micro-nanostructures,thus enabling further increase of hydrophobic stability of dynamic droplet impacts.At the same time,this microporous structure avoids the direct friction and wear of the material surface,which can greatly improve the durability.This biomimetic microporous structure can be combined with the surface microgroove structure in the later stage,which is conducive to the natural slide of the droplet,thus further enhancing its hydrophobicity and expanding its application in the field of drag reduction and preventing ice formation.The experimental results show that the parameters of laser scanning speed and power value have a great effect on the hydrophobic properties of the biomimetic surface.The best hydrophobic properties are obtained when the laser power is 9 mW,the scanning speed is 10 mm/s,and the processing pitch is 10μm,and the contact angle is more than 150°.In the durability comparison experiment,after 200 to 1000 times of friction,the decrease of the contact angle of the finished fluoro-silicone resin layer is significantly lower than that of the other two groups of experiments.The results show that the finished fluoro-silicone resin layer has excellent durability.