Highly stretchable, moisture-permeable, on-skin electrodes from liquid metal and fiber mat

Abstract

Stretchable epidermal electronics with stable electrical performance have been widely applied in numerous fields, including advanced medical therapy, wearable electronics, soft robotics, and human–machine interaction. However, conventional stretchable devices, which typically integrate a pliant substrate and a conductor, often encounter inferior electrical performance under sustained or intense stretching due to poor stretchability, limited permeability, and the notable disparity in Young's modulus between the substrate and the conductor. This mechanical discord intensifies problems such as reduced durability and inconsistent conductivity. In this work, we address these limitations by devising a liquid metal-based flexible conductor via an innovative direct coating method. This conductor, supported by an electrospun fiber nanomesh, reveals markedly enhanced permeability through a pre-stretch activation process. The resulting electrode demonstrates remarkable electrical conductivity reaching 3730 S cm^-1, superior permeability with a water vapor transmission rate of 40.2 g m^-2 h^-1, and extraordinary stretchability (>2000% strain), coupled with exceptional mechanical durability. The liquid metal fiber mat structure allows for the creation of breathable, on-skin electronics capable of long-term electrophysiological monitoring, rendering it ideal for continuous health monitoring applications.

Keywords

epidermal sensors / highly stretchable / liquid metal / long-term electrophysiological monitoring / moisture-permeable

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