Control of Liquid Metal Droplets using Liquid Crystallinity

Abstract

Recent advances of soft electronics realize its futuristic applications such as stretchable device, electronic skins, and soft robotics. Liquid metals (LMs), which have metallic and fluidic attributes at room temperature, have explored as conductive filler for soft electronics. However, previous approach such as shear mixing LMs in polymer matrix needs high LM loading (over 85 wt%) to form a conductive pathway, causing leakage of LMs. Also, micro-scale control of LMs remains a challenging problem. Here, we integrate the LMs with liquid crystals (LCs) which are widely used as a molecular/colloidal template. The LM droplets in LCs cause reorientation of LCs around the droplet showing broken symmetry of LC configuration. When we apply AC electric field to the LM droplets in LCs, they move along the LC molecular axis due to their broken symmetry, forming microscopic linear chain of LMs. The LM chains can be a conductive pathway connecting electrodes. Namely, the combination of LMs and LCs realizes micro-scale manipulation of LMs with very low LM loading (~5 wt%) in the LCs. This work was supported by NRF (2021R1A4A1030944) and Samsung Electronics Co., Ltd (4.0024479).