On‐Demand Manipulation of Liquid Metal Droplet via van der Waals Adhesion

Abstract

Abstract The actuation of liquid metal droplets is the core in the development of future liquid metal‐based soft robotics or devices. In the present study, an intriguing phenomenon of actuating liquid metal droplets via van der Waals adhesion is introduced. Through the electrochemical interaction between liquid metal and nickel in an acid solution, the continuously generating hydrogen bubbles form capillary adhesion to surfaces, which provide the force bridge between two metals. Based on this mechanism, liquid metal can not only be manipulated by directly dragging a nickel rod, but also accurately and stably be driven by magnetic field due to the magnetism of nickel. In particular, the magnetic manipulation method involved in this study does not change the chemical nature of the liquid metal. With all the distinctive properties, this van der Waals force‐based liquid metal actuation may offer numerous inspirations in various fields including soft robotics, flexible electronics, and microfluidics.