Chemical Surface Metallization for Elastomers with Biphasic Liquid Metals

Abstract

Growing interest has been received in lightweight, cost-effective, and easily processable conductive materials with the rapid development of wearable electronics, smart robotics, and bioengineering. Flexible polymer metallization is the most prevalent method to inherit the merits of both metals and elastomers. This work explores and optimizes the metallization process and successfully fabricates a three-layer flexible conductive material through electroless copper plating and gallium electroplating on the surface of elastomers. The material obtained in this work exhibits strong adhesion between the coating layer and soft polymer (peel strength: 1.52 N/mm), considerable stretchability (elongation at break: 507%), high electrical conductivity (3.11 × 10⁴ S/m), and outstanding electromechanical stability (2000 cycles). Interestingly, the integration with photolithography enabled selective metallization on specific regions of the elastomer substrate, providing applications in flexible and intelligent devices. This work contributes to the advancement of surface treatment technologies based on the combination of metals and elastomers, which is beneficial for diverse advanced technologies including E-skin, wearable electronics, microelectronics, and nanotechnology.