木材表面SiO_2/环氧树脂/氟硅烷复合超疏水膜的构建

Fabrication of superhydrophobic SiO_2/epoxy resin/fluorinated alkylsilane nanocomposite coatings on wood surfaces

【目的】为获得具有良好机械耐磨性的超疏水木材,构建了木材表面SiO_2/环氧树脂/氟硅烷复合超疏水膜。【方法】采用两步法在木材表面构建有机/无机复合超疏水涂层,在木材基底预置透明环氧树脂底层以覆盖木材表面天然微沟槽结构,然后构建SiO_2/环氧树脂/氟硅烷(FAS)复合超疏水薄膜。采用场发射扫描电子显微镜、原子力显微镜以及傅里叶红外光谱仪对超疏水涂层的微观形貌和化学组成进行表征,并测试其疏水、疏油和机械耐磨性能。【结果】木材表面复合超疏水涂层具有精细的微/纳米二元粗糙结构,该结构协同低表面能物质FAS,使木材表面不仅具有良好的超疏水性能(水静态接触角为153°,滚动角低于4°),而且疏油(乙二醇接触角为146°,滚动角低于11°);经砂纸多次磨擦后木材表面水接触角和滚动角基本不变,超疏水性能保持稳定,超疏水涂层的微纳米结构及疏水物质依然保留,表现出良好的机械耐磨性。【结论】有机/无机复合超疏水涂层体系中,环氧树脂由于黏结作用使得SiO_2纳米粒子与木材基底形成牢固的结合,从而赋予涂层良好的机械稳定性。

[ Objective ] In order to obtain mechanically durable superhydrophobic wood, a superhydrophobic nanocom- posite film using silica/epoxy resin/fluorinated alkylsilane （FAS） was constructed on the wood surface. [ Method] Super- hydrophobic organic/inorganic nanocomposite coatings were fabricated on wood surfaces via a two-step process, which involved the application of a primer coating of transparent epoxy resin to cover the naturally micro-grooved surface struc- ture, and subsequent construction of a superhydrophobic nanocomposite film using silica/epoxy resin/FAS. The surface morphology and chemistry of the superhydrophobic coatings were characterized by field-emission scanning electron mi- croscopy （FE-SEM） , atomic force microscopy （AFM） , and fourier transform infrared spectroscopy （FTIR）. The hydro- phobicity, oleophobicity, and mechanical durability of the coated wood were tested. [ Result ] The results indicated that the well-developed microstructures with dual-scale roughness patterns and the low-surface-energy FAS in the coatings are believed to be responsible for the good superhydrophobicity （with a water contact angle of 153~ and a sliding angle less than 4~） and oleophobicity （with a glycol contact angle of 146~ and a sliding angle less than 11~）. The water contact an- gles and sliding angles of the coated wood exhibited negligible changes after repeated abrasion by sandpaper, indicating sustainable non-wetting properties. Meanwhile, the surface microstructures with dual-scale roughness and the low-surface- energy materials in the coatings were retained, exhibiting remarkable durability against sandpaper abrasion. [ Conclusion ] tn this organic/inorganic hybrid coating system, the epoxy resin acts as a binder to anchor the SiO2nanoparticles tightly on the wood substrate, thus endowing the superhydrophobic coatings with remarkable mechanical durability.