Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
Nanotechnology. 2011 Jan 21;22(3):035703. doi: 10.1088/0957-4484/22/3/035703. Epub 2010 Dec 9.
We show that nanoporous anodic alumina films, with pore diameters in the range 10-80 nm, can be transformed from being very hydrophilic (or super-hydrophilic) to very hydrophobic (or super-hydrophobic) by coating the surface with a thin (2-3 nm) layer of a hydrophobic polymer. This dramatic transformation happens as a result of the interplay between surface morphology and surface chemistry. The coated surfaces exhibit 'sticky' hydrophobicity as a result of ingress of water into the pores by capillary action. The wetting parameters (contact angle and contact angle hysteresis) exhibit qualitatively different dependences on pore diameters in coated and uncoated films, which are explained by invoking appropriate models for wetting.
我们表明，通过在表面涂覆一层薄（2-3nm）的疏水性聚合物，可以将孔径在 10-80nm 范围内的纳米多孔阳极氧化铝薄膜从非常亲水（或超亲水）转变为非常疏水（或超疏水）。这种剧烈的转变是由于表面形貌和表面化学之间的相互作用。由于毛细作用，水进入孔隙，涂层表面表现出“粘性”疏水性。通过引入适当的润湿模型，可以解释润湿参数（接触角和接触角滞后）在涂层和未涂层薄膜中的不同的依赖关系。
