Simple and Effective Patterning Method of Liquid-Metal-Infused Sponge Electrode for Fabricating 3D Stretchable Electronics

Abstract

Stretchable electrodes have emerged as a promising technology for soft robotics and wearable devices. One fabrication method that guarantees sustained elasticity and high conductivity is directly filling or printing an elastic substrate with liquid metal (LM). However, it is difficult to create patterns with complex or 3D shapes, such as hole patterning, integration electrodes, and flexible breadboards. Therefore, a simple and effective patterning method for fabricating 3D stretchable electronics using LM electrodes is proposed in this study. The LM-infused sponge electrode is fabricated by loading LM onto a polydimethylsiloxane (PDMS) sponge, which is fabricated using the salt-leaching method in PDMS patterned by replica molding. The LM-infused sponge electrode exhibits a minimal change in terms of resistivity under strain, bending, and twisting ( increment R < 0.01 Omega cm(-1)). This enables various devices to be driven by the production of flexible breadboards, which makes it possible to integrate the proposed model into commercial electronics. Finally, a stretchable tactile sensor (self-capacitive and self-powered) is fabricated by integrating stretchable electrodes using only the LM-infused sponges. In the future, stretchable electrodes fabricated in this manner can be used in various applications, such as soft robots and wearable devices.