铝合金基体上超疏水表面的制备

Fabrication of Super-Hydrophobic Surfaces on Aluminum Alloy

采用简单化学刻蚀的方法制备出多晶铝合金基体上的超疏水表面。刻蚀后的铝合金表面经过氟化处理后具有了超疏水的性质,水滴与表面的接触角达到156°,接触角滞后为5°。通过对表面进行扫描电镜分析可知,超疏水铝合金表面上具有了由长方体状的凸台和凹坑构成的深浅相间的微纳米结构,这些微纳米结构相互连通形成凹凸不平的"迷宫"结构,这种结构经氟化修饰后,可捕获空气,形成水与基底之间的气垫,对表面超疏水性的产生起到了关键的作用。文中对铝合金基体上的超疏水现象以Cassie理论进行了分析,结果表明,水与表面形成了非均匀接触,约12%的面积是水滴和基体接触,而有约88%的面积是水滴和空气接触。研究中考查了不同刻蚀时间以及不同刻蚀液浓度对表面疏水效果的影响。最佳制备条件为:盐酸溶液浓度为4.0mol·L·1,刻蚀时间为12min。

A simple chemical etching method was developed for fabricating the super-hydrophobic surface on polycrystalline aluminum alloy. After the chemical etched surface was treated with fluorination, the aluminum alloy surface exhibits a super-hydrophobic property with water contact angle of 156° and contact angle hysteresis of 5°. The surface morphology was inspected with scanning electron microscope, and it was found that the surface is configured in a labyrinthic structure with plateaus and caves of micro-nanostructure. The caves in the labyrinth trap air in them, which can form air cushion between water and the surface. This micro-nano hierarchical structure plays an important role in the formation of the super-hydrophobicity. The super-hydrophobic phenomenon of the prepared surface was analyzed with Cassie theory, and the result shows that only about 12% of the water contact surface is contacted with the metal substrate and the rest 88% is contacted with the air cushion. The effects of the etching time and the etchant （HCI solution） concentration on the super-hydrophobicity were investigated, and the optimum etching conditions found are 12 min of etching time and 4.0 mol·L^-1 of HCI solution concentration.