Stretchable and translucent liquid-metal composite mesh for multifunctional electromagnetic shielding/sensing and Joule heating

Abstract

Flexible liquid metal (LM)-based composite materials with strain-undiminished electromagnetic interference (EMI) shielding effectiveness (SE) and multifunctional integration are attracting great attention due to the urgent need for flexible electronic and wearable devices. Herein, stretchable and translucent polydimethylsiloxane/LM composite mesh (PLM) is developed by introducing highly deformable LM filler into elastomer and constructing conductive mesh structures by cast molding and mechanical sintering, which shows strain-enhanced EMI SE without a significant decrease in light transmittance due to the contribution of stretch-induced enhanced conductivity, mesh densification, and orientation. The linear response of relative SE change with tensile strain allows the PLM to exhibit ideal EM sensing characteristics, superior to most reported stretchable EMI shields. The oriented mesh structure endows the stretched PLM with anisotropic EMI SE under rotation, revealing a feasible means to realize tunable SE in a tensile state. More importantly, the high conductivity and deformability of the LM network further provide the PLM with excellent and relatively stable Joule-heating performance when served as a stretchable Joule heater. This work offers a new strategy for developing multifunctional stretchable LM-based composites that can achieve strain-enhanced EMI SE and ideal EM sensing capability without significantly sacrificing the light transmittance and Joule-heating performances under stretching.