A Super Anisotropic Wetting Microstructure Based on Combination of Sharp Edge and Sharp Corner

Anisotropic wetting is important in industrial, medical and agricultural applications. In this paper, a novel microstructure performing prominent ultra-anisotropic wetting properties is proposed, with MEMS fabrication process. This microstructure possesses both sharp edge and sharp corner (SESC) in topography. The sharp edge can hinder liquid spreading significantly, whereas the sharp corner enhance spreading. By lithography technology on polymer film, Parylene-C, the microstructure can be tailored into different shapes to achieve various liquid spreading properties, two of which are demonstrated here. 2-D SESC microstructure illustrates ultra-high contact angle difference in parallel and perpendicular directions as high as 93.8°, as well as bidirectional wetting properties. Another microstructure, namely 3-D SESC microstructure, demonstrates specific unidirectional wetting properties. The unique microstructure proposed in this paper provide new ideas for application of controlling liquid spreading on surface. [2019-0077].