Influence of surface topography and chemical structure on wettability of electrodeposited ZnO thin films

摘要

The wettability of electrodeposited zinc oxide (ZnO) thin films has been rationally controlled by individually engineering surface topography and surface chemical structure. We have studied the wettability of hydrophobic ZnO thin films that were rendered ultrahydrophobic by coating with low surface-energy self-assembled monolayer of octadecyltrichlorosilane and also hydrophilized by annealing at elevated temperature in air ambient. The as deposited ZnO film was hydrophobic with contact angle of around 105° ± 3° against water, while the annealed films were distinctly hydrophilic. The silanized films were ultrahydrophobic with a contact angle of 143° ± 3°. The films could be successfully tailored to obtain hydrophilic, hydrophobic as well as ultrahydrophobic behavior. It is likely that similar tunable wetting behavior may be observed in other oxide materials also.