Determination of surface properties of various substrates using TiO2 nanorod coatings with tunable characteristics

We present a novel approach to cover different substrates with thin light-sensitive layers that consist of org.-capped TiO2 nanorods (NRs). Such NR-based coatings exhibit an increasing initial hydrophobicity with increasing NR length, and they demonstrate a surface transition from this highly hydrophobic state to a highly hydrophilic one under selective UV-laser irradn. This behavior is reversed under long dark storage. IR spectroscopy measurements reveal that light-driven wettability changes are accompanied by a progressive hydroxylation of the TiO2 surface. The surfactant mols. that cover the NRs do not appear to suffer for any significant photocatalytic degrdn.