Liquid Metal Motor

Abstract

As an emerging soft material, liquid metal has demonstrated enormous potential for developing high performance functional devices and machines. However, current liquid metal enabled machines suffer from several issues, such as the requirement of a liquid environment, generation of weak actuating forces, and insufficient maneuverability. These restrictions limit the application of liquid metal in constructing more complex, flexible and powerful actuating systems. Here, a motor is developed based on the electrical actuation of liquid metal droplets without the need for conventional electromagnets. The approach is distinguished by (1) the encapsulation of electrolyte and multiple liquid metal droplets within an enclosed system, and (2) the creation of stable and continuous torque outside a liquid environment. In addition, an electrical brush is introduced to contact liquid metal with solid electrodes and operate the motor with low friction. The parameters affecting the actuation behavior are further investigated. Moreover, the versatility and maneuverability of the motor is demonstrated by applying it to drive untethered vehicles and boats. The unique driving mechanism endows the liquid metal motor with several advantages, including low friction, no sparking, low noise, versatile working environment, and being built from soft materials that could offer new opportunities for developing soft robotics.