Cost-effective surface modification for Galinstan® lyophobicity

In this paper we investigate the feasibility of using a cost-effective fabrication method based on sandblasting, chemical etching and spray coating processes, to render common surfaces to be non-wettable by Galinstan®. Although Galinstan® is a non-toxic liquid metal alternative to mercury, the viscoelastic and extremely wetting characteristics of Galinstan® have been the major bottleneck limiting the wide applicability of the gallium-based liquid metal. This paper tries to accomplish non-wettability to Galinstan® by combining surface texture and chemistry with the unique property of Galinstan®, that is, its high surface tension and yield strength that prevent the penetration of the liquid metal into surface asperities. Fabricated surfaces resemble traditional superhydrophobic (water-repellent) surfaces, and exhibit a superior non-wettability to Galinstan® as quantified by high static and dynamic contact angles, small hysteresis, as well as impact resistance. Reported fabrication method based on sandblasting, etching and spray coating is easily applicable to various surfaces ranging from metals, ceramics, to plastics and is scalable to large surfaces.