Fabrication of a super-hydrophobic nanofibrous zinc oxide film surface by electrospinning

We report a new approach for fabricating a super-hydrophobic nanofibrous zinc oxide (ZnO) film surface. The pure poly(vinyl alcohol) (PVA) and composite PVA/ZnO nanofibrous films can be obtained by electrospinning the PVA and PVA/zinc acetate solutions, respectively. After the calcination of composite fibrous films, the inorganic fibrous ZnO films with a reduced fiber diameter were fabricated. The wettability of three kinds of fibrous film surfaces were modified with a simple coating of fluoroalkylsilane (FAS) in hexane. The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). It was found that the pure PVA fibrous films maintained the super-hydrophilic surface property even after the FAS modification. Additionally, the WCA of composite fibrous films was increased from 105 to 132 degrees with the coating of FAS. Furthermore, the surface property of inorganic ZnO fibrous films was converted from super-hydrophilic (WCA of 0 degrees) to super-hydrophobic (WCA of 165 degrees) after the surface modification with FAS. Observed from XPS data, the hydrophobicity of FAS coated various film surfaces were found to be strongly affected by the ratio of fluoro:oxygen on the film surfaces. (c) 2007 Elsevier B.V All rights reserved.