Reversible Surface Wettability by Silanization

The chemistry and wettability of oxygen containing surfaces can be conveniently modified by silanization with various organosilanes which form SiO bonds on the surface. This work shows that a superhydrophobic nanoporous polymer coating can be reverted to its previous hydrophilic state by removing the fluoroalkyl silane with fluoride anions using tetrabutyl ammonium fluoride. This leads to a completely reversible process of silanization and desilanization which can be performed in less than 2 min for each step as proven by droplet shape analysis and secondary ion mass spectrometry. Additionally, the desilanization solution can be applied spatially by an automated liquid dispenser or manually by a brush, leading to patterns with different wettability, such as droplet microarrays or liquid channels.