Hydrophobic anatase TiO(2)-based thin films modified with Al, Cr derivatives to reach reversible wettability control.
Polycrystalline anatase TiO(2)-based thin films with surface roughness were fabricated using a sublimation method. Their surfaces showed hydrophobicity with a water contact angle (CA) higher than 130 degrees when stored in the dark. For the films, the hydrophobic conversion behavior and critical CA depended on surface morphologies. The higher hydrophobic conversion rate and higher critical CA were explained by the smaller r in the Wenzel equation and the smaller f (f = 0.56, 0.30) in the Cassie equation, respectively. Moreover, good reversibility between hydrophobicity (CA = 130 degrees ) and high hydrophilicity (CA = 0 degrees ) was observed by alternating between UV light irradiation and dark storage. The combination of chromium oxide with anatase TiO(2) markedly shortens the period of hydrophobic conversion from 12 to 5 days.
Irie
Hiroshi
H
Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. irie-hrs@light.t.u-tokyo.ac.jp
Tsuji
Ken-Ichi
K
Hashimoto
Kazuhito
K
D000535:Aluminum / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008855:Microscopy, Electron, Scanning; D014025:Titanium / Q000737:chemistry*; D017155:Wettability
D002857:Chromium; C009495:titanium dioxide; D000535:Aluminum; D014025:Titanium