Fast and highly reversible switching of wettability through macroscopic shape change

Abstract

A smart surface with switchable wettability has many important technological applications. Here we report an intelligent surface that can fast and reversibly switch its wettability through macroscopic shape change. The reported surface is constructed by integrating a superhydrophobic copper mesh into a polyvinyl alcohol (PVA) gel synthesized via solvent exchange. By elaborately tuning the pressure exerted on it, the wettability of the integrated mesh is able to vary between superhydrophobicity and superhydrophilicity in a few seconds, and the switching occurs up to 500 cycles. Reversible switching is found to be mainly determined by the adhesion force between the copper mesh and the polymer gels. Interestingly, reversible switching of superhydrophobicity/superhydrophilicity and superoleophobicity/superoleophilicity in liquid media can also be achieved through a similar strategy. The present investigation offers a facile strategy to fabricate an integrated smart surface with switchable wettability aiming for many important technological applications.