Towards Biomimetics of Superhydrophobic Water Strider Feet (poster)

Abstract

This contribution summarizes first characterization results of superhydrophobic water strider feet with the vision to understand the interplay of morphology and chemistry to ultimately mimic such unique functionalities for future applications. The study started with chemical aspects to validate the likely existence of a wax layer. For that, separated legs were exposed to CHCl3 under controlled conditions, followed by the chemical analyses of the solution. Fourier Transformed - Infrared Spectroscopy (FT-IR) confirmed the expected wax layer as first element for the superhydrophobic functionality. In a second step, individual feet were studied via Environmental Scanning Electron Microscopy (ESEM). For nanoscale studies, we prepared ultrathin cross sections via Ultramicrotomy (UM) and subjected them to Transmission Electron Microscopy (TEM). Together with Atomic Force Microscopy (AFM) studies on UM-prepared block-faces, we could confirm a partial wax coverage by a direct comparison of native and CHCl3 treated feet. In a next step, we conducted ESEM-based, dynamic in situ studies, which directly revealed the hydrophobic H2O condensation on native legs. Currently, we work on a mechanical setup to access friction coefficients of differently treated legs, inspired by the Cavendish method. By that, we will be able to separate between morphology- and chemistry-related contributions to understand the origin of superhydrophobic water strider legs.