Injectable Transformation of Liquid Metal

Abstract

The room temperature liquid metal (RTLM) is emerging as an ideal material for fabricating microdroplets owing to its strong surface tension and easy phase switching property. In this sense, a bottle of liquid metal can be easily transformed into a large amount of tiny liquid metal droplets. Given specific control via external fields such as mechanical, electrical, chemical, boiling, or acoustic, different sized droplets can be quickly obtained in large amount. Such transition mechanism between large pool of liquid metal and its small-sized objects can be applied for making discrete soft machine which will also be illustrated in later chapters. Along this direction, Yu et al. [1] found out a low-cost and technically simple way for preparing metal droplets. They demonstrated a channelless fabrication method based on stream jetting and self breaking up mechanisms of the RTLM when injected into and interact with the matching solution. The role of such method in the fabrication is rather diverse. For example, the injected assembly of liquid metal droplets can be directly applied to construct a three-dimensional porous metal block with foam structures inside. Apart from the above mechanical injection, electrical field was also disclosed for the automatic generation of liquid metal droplets. Overall, the injection strategy provides an extremely simple way for large-scale fabrication of liquid metal microdroplets and particles which have rather important practical values. It also suggests a highly efficient approach for visualizing and investigating the fundamental mechanisms of fluids interactions between RTLM and general solution. This chapter is dedicated to present the basic strategy to realize the injectable transformation of liquid metal when subject to various external forces and discuss their potential applications.