Photoinduced cleaning of water-soluble dyes on patterned superhydrophilic/superhydrophobic substrates

Herein we present a novel but simple method to fabricate photoinduced cleaning substrates with patterned superhydrophobic hierarchical silicon cone arrays (SCAs) and superhydrophilic TiO2nanorod clusters (TNCs). In our experiment, the photoinduced cleaning properties of the obtained substrate are investigated by repeatedly adsorbing and decomposing rhodamine B (RhB) molecules for at least six cycles. In addition, we demonstrate that the low-surface-energy coating on the superhydrophobic areas is stable, resulting in the high wettability contrast being well preserved during the renewal process. This straightforward method may open up new possibilities for the practical use of microchips with patterned superhydrophobic and superhydrophilic areas.