Plasma deposition of superhydrophobic Ag@TiO2 Core@shell nanorods on processable substrates

This work reports the low temperature plasma formation of Ag@TiO2 nanorods (NRs) on processable substrates. The layers have been analyzed by electron microscopy and secondary ion mass spectroscopy. The NRs morphologies suggest that the plasma sheath, the high mobility of the silver and the incoming direction of the precursor moieties are key factors determining their shape, dimensions, and tilting orientation. Both amorphous and anatase Ag@TiO2 NRs surfaces are superhydrophobic, and turn into superhydrophilic by irradiation with UV light. This wetting behavior is discussed by considering the water penetration in the inter-NR space during the light-mediated transformation. The growth of vertical and tilted Ag@TiO2 core@shell nanorods by PECVD is demonstrated. Control on the experimental parameters allows the formation of NRs with tailored morphology on processable substrates at mild temperature. High density NRs surfaces present superhydrophobic behavior tunable till superhydrophilic under UV light. Wetting mechanism and superhydrophobic- superhydrophilic transition are explained within the Cassie-Baxter and Wenzel models. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Peer Reviewe