Anomalous adhesive superhydrophobicity on aligned ZnO nanowire arrays grown on a lotus leaf

Abstract

We demonstrate a conceptually novel approach to incorporate biological substrates with synthetic nanowires. Vertically aligned single crystal ZnO nanowire arrays were directly grown on the lotus leaf surface using a simple hydrothermal method. We observed a strong adhesive superhydrophobicity on this artificial/natural architecture, which is paradoxical to conventional observations of superhydrophobicity on the lotus leaf. Surface modification of as grown ZnO nanowire arrays with low surface energy fatty acids retains the repelling nature of the surface. To the best of our knowledge, this is the first report on growth of any kind of synthesized nanostructures on naturally occurring biological substrates. This unique and distinctive approach has fundamental significance towards technological novelties in biomimetics as well as nano-biotechnology. We envision fruitful applications of this approach in diverse areas of nanotechnology with strategic exploitation of this “material engineering on real biological surfaces”.