Abstract:

This work aimed to fabricate a superhydrophobic surface on paper substrate by roller coating with modified micro/nano-TiO₂, and evaluate the robustness, self-cleanability and hydrophobic performance of the coating paper surface. First, TiO₂ particles in microns and nanometers were hydrophobic modified by 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) and γ-aminopropy- ltriethoxysilane. Then, the modified micro/nano TiO₂ particles were coated on paper substrate surface. The chemical compositions of modified micro/nano TiO₂ were analyzed by FTIR and the surface structure of coating paper was characterized by SEM. The superhydrophobicity, robustness and self-cleaning property of the coating surface were evaluated by water contact angle, abrasion testing and self-cleaning testing. FTIR analysis of modified TiO₂ showed that the multiple stretching vibration peaks of C—F bond appeared between 1000~1500cm^-1, indicating that POTS was bound to the surface of TiO₂ through chemical bonds and the hydrophobic modification of TiO₂ was successful. SEM analysis of coating paper surface indicated that TiO₂ particles with micron and nanometer size were evenly distributed on the surface of paper substrate. The coating paper was a rough surface with micro-nano structure similar to that of lotus leaf. Water contact angle and rolling angle of coating paper surface were 153°±1.5° and 3°±0.5°, respectively, so water droplet was spherical on the coating surface and easily fall off, showing that coating paper surface was excellent superhydrophobic property. After the coating paper was immersed in water for 7d, the contact angle did not change significantly, indicating that the coating had good hydrophobic stability. After 10 cycles of abrasion testing on the coating paper surface, water contact angle and rolling angle of coating paper surface were 150° and 9°, respectively. It indicated that the mechanical friction did not cause significant damage to the chemical composition and rough structure of the coating paper surface, and the robustness of superhydrophobic surface was very well. Furthermore, self-cleaning testing showed that the coating paper surface was good self-cleaning and anti-fouling performance. The preparation process of superhydrophobic surface was simple and easy to be industrialized, and provided a novel convenience approach to constructing super-hydrophobic surface with excellent comprehensive performance.

Key words: surface, nanoparticles, composites, superhydrophobic, coating, paper substrate

摘要：

采用辊式涂布的方法在纸基材料上构建超疏水表面，并对超疏水表面的牢固性、自清洁性和疏水性能进行评价。用γ-氨丙基三乙氧基硅烷和1H,1H,2H,2H-全氟辛基三乙氧基硅烷（POTS）对微米级和纳米级两种尺寸的TiO₂粒子进行疏水改性处理，然后将改性后的微/纳米TiO₂涂布在纸基材料表面。采用红外光谱（FTIR）对改性后的微/纳米TiO₂的化学组成进行了分析，采用扫描电镜（SEM）对涂布纸表面结构进行了表征，通过接触角、耐磨性和自洁净测试评价了涂层表面的超疏水性、牢固性和自清洁性。改性TiO₂的FTIR分析显示在1000～1500cm^-1之间出现多个C—F键的伸缩振动峰，表明POTS通过化学键与TiO₂表面发生了结合。涂布纸表面的SEM分析可以看出，纸基材料表面上均匀分布了微米和纳米尺寸的TiO₂颗粒，具备了类似荷叶表面微-纳结构的粗糙表面。涂层表面的水接触角为153°±1.5°，滚动角为3.5°±0.5°，水滴在涂层表面呈球形，极易滑落，涂层在水中浸泡7天后，接触角没有发生明显变化，表明纸张表面具备了优异的超疏水性能，且疏水稳定性较好。涂层表面经过10次循环磨损试验后，接触角仍能达到150°，滚动角为9°，表明机械摩擦没有对涂布纸表面的化学成分和粗糙结构造成明显的破坏，超疏水表面的牢固性较好。自洁净测试表明，涂布纸表面具有良好的自清洁和防污性能。该工艺过程操作简单，易于实现工业化生产，为在纸基表面构建综合性能优异的超疏水表面提供了一种新的便利途径。

关键词: 表面, 纳米粒子, 复合材料, 超疏水, 涂布, 纸基