Open Space Transportation of Liquid Metal Droplets by Magnetically Active Microwall Arrays

초록

Recently, gallium-based liquid metal has attracted a great attention as a non-toxic conducting material in soft electronics for alternatives to mercury. Positional control of liquid metal droplet can be applied to on/off switch in manipulating electric conduction. However, current methods to transport liquid metal droplet are limited in confined path, and thus limits application for electronics without channel. Herein, we suggest on-demand channel-free control of liquid metal droplet by magnetic actuation of microwall arrays. The magnetically active microwall is a composite with large height to width aspect ratio (~7) consisted with polydimethylsiloxane (PDMS) and iron particle. The top parts of the microwalls bend in response to an external magnetic field, while the bottom parts of the microwalls are immobilized by a neat PDMS substrate which is magnetically inert. To control liquid metal droplet transportation, we investigated various parameters related to the bending actuation and spacing between the microwalls. Finally, we demonstrate merger of two liquid metal droplets by managing transportation direction of each droplet.