HYDROFAKIR · Roughness design towards reversible non- / full-wetting surfaces: From Fakir Droplets to Liquid Films

Creating tunable surfaces that are able to undergo reversible transitions between superhydrophobic and superhydrophilic behaviour is a challenging and vital issue due to their potential use in applications involving self cleaning, very low flow resistance and liquid handling without moving mechanical parts. Superhydrophobic surfaces arising from micro-scale roughened hydrophobic materials spontaneously exhibit transitions to become superhydrophilic when their material wetting properties are suitably modified by external stimuli. The reverse transition, however, requires external actuation/ perturbation which can be strong as to deteriorate the liquids handled and therefore limit the use such techniques in applications. Here we plan to combine continuum and mesoscale computational analysis of wetting phenomena in solid surfaces to create designer roughness that will minimize, or even eliminate, the strength of the actuation required to achieve full- to non-wetting reversibility. The modelling will be done in a continuous dialogue with surface fabrication and wetting tests. Wetting experiments will be performed along with novel microactuation techniques for liquid interfaces.