Design, microfabrication and evaluation of robust high-performance superlyophobic surfaces

High-performance superlyophobic surfaces (SLSs) showing extremely low wettability for various liquids including water and oil are microfabricated following universal design criteria and formulated rules, and their wetting and hydrodynamic performances are systematically evaluated. Four design criteria are proposed to achieve reliable air-entrapped Cassie-Baxter (C-B) state for various liquids, especially low-surface-tension oils by considering the pressure balance and curvature requirement, as well as the pinning and suspending condition. By formulating the geometric design rules, a T-shaped configuration with a slight undercut is preferred as robust 3D structure for microfabricated high-performance of SLS. The static and dynamic contact angles (CAs) of water and hexadecane on SLS can be well tuned by varying the solid fraction. On the high-robustness and low-adhesion SLS, CAs up to 167 degrees for hexadecane and 170 degrees for water, and low contact angle hysteresis (CAH) similar to 8 degrees have been achieved. However, CAs on SLS cannot be well explained by three existing wetting models, which requires more efforts to exactly depict the droplet behavior on SLS. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.