A super-lyophobic PDMS micro-tunnel as a novel microfluidic platform for oxidized Galinstan®

We report a micro pillar array-based super-lyophobic poly(dimethyl siloxane) (PDMS) micro-tunnel as a novel microfluidic platform for oxidized Galinstan^®. Liquid-metal alloy, Galinstan^® was expected to be widely utilized in many MEMS applications due to its favorable properties. However, the fact that Galinstan_® gets easily oxidized and wets on almost nearly any surface is the difficult challenge for utilization of Galinstan^®. We studied various pitch distance micro pillar arrays and evaluated lyophobicity of Galinstan^® using static contact angle and sliding angle. A unique approach to fabricate 3-dimensional (3-D) lyophobic micro-tunnel structure was designed using flexible PDMS, which can overcome the limitation of current lithography techniques. It was demonstrated the movement of oxidized Galinstan^® without wetting.