Modeling of Wetting Transition of Liquid Metals on Organic Liquid Surfaces

Wettability of liquid metal gallium is of vital significance in the field of modern industries, such as direct writing printing and microfluidics. A liquid interface is a recently developed and promising approach to regulate wettability but has not been well applied in liquid metals yet. This study focuses on the wetting performance of gallium droplets on organic liquid films. The results show that the organic liquid film could change the wetting state of the gallium droplet. Based on the solid substrate roughness and surface tension of the organic liquid, we could estimate whether the gallium droplet is in a slippery Wenzel or a Cassie state. Subsequently, we apply the thermodynamic stable model on different organic liquid films by spreading parameters to predict a priori whether an arbitrary combination of solid roughness and organic liquid is suitable for designing lubricant-infused surfaces (LIS) used in gallium droplets. More interestingly, we found that the "cloaking" could delay surface oxide formation, which will benefit the manipulation of liquid metal droplets. This paper would provide a better understanding of wettability of liquid metal on an organic liquid surface.