Reversible wettability of tungsten trioxide films with novel dandelion-like structures

Abstract

Tungsten trioxide (WO 3) films with novel dandelion-like structures were prepared by spin-coating a sol of WO 3 with CTAB (cetyltrimethyl ammonium bromides) on quartz substrates. The resultant WO 3 films were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The wettabilities of the WO 3 films were evaluated by contact angle (CA) measurements. It was found that the WO 3 film exhibited superhydrophilicity under UV light irradiation, whereas after storage in the dark for a certain time, it turned to be superhydrophobic. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.