Stretchable and Permeable Liquid Metal Micromeshes Featuring Strain-Insensitive Resistance Through In Situ Structural Transformations

Abstract

Gallium-based liquid metals hold promises for applications in stretchable electronics and beyond. However, these materials often encounter notable resistance increases during stretching and have negligible permeability to gases and liquids. This study presents an in situ structural transformation mechanism to create stretchable and permeable liquid metal micromeshes with strain-insensitive resistance. These micromeshes are fabricated by spin-coating liquid metal onto microfiber textiles and subjecting them to several stretching cycles. Consequently, the micromeshes transform from a smooth finish to wrinkled textures due to the growth in their oxide nanoskins. The distinct microstructure alters the stretching-relaxing mode to folding-unfolding, thereby minimizing fluctuations in resistance. The practical significance of this development is demonstrated through the fabrication of wearable heaters and LED matrices using transformed liquid metal micromeshes. Moreover, when integrated into Janus textiles featuring unidirectional water transport, these micromesh conductors act as sensing electrodes capable of acquiring high-fidelity biopotentials, even during intense sweating. These advancements highlight the capability of ambient air as a powerful reactive environment for tailoring the properties of microscale liquid metals.