A strategy of fast reversible wettability changes of WO3 surfaces between superhydrophilicity and superhydrophobicity

As prepared WO3 nanostructure films on alumina or tungsten substrates by a facile hydrothermal method exhibit a superhydrophilic property An effective strategy is proposed to control the wettability of WO3 films in a reversible manner between superhydrophilicity and superhydrophobicity with a rapid response By controlling the process of adsorption/desorption of n-dodecanethiol associated with the light-induced plating Ag nano grains on WO3 nanostructures it only takes about 25 min to fulfill the wettability change from superhydrophilicity to superhydrophobicity and only 30 s to finish the reversed change Moreover the contact angles of WO3 surface can be tuned by controlling the etching time of superhydrophobic WO3 surfaces in a solution of nitric acid containing 5 mM sodium dodecyl benzene sulfonate Electrowettmg process is successfully demonstrated to trap a water drop onto the superhydrophobic WO3 surfaces Considering WO3 is one of typical electrochromic materials researches on the effect of coupling between electrowettmg and electrochromic properties would be more promising (C) 2010 Elsevier Inc All rights reserved