A permeable, metal-like conductivity, stretchable, strain-insensitivity, self-assembled and rapidly formed Janus-structured e-skin

Abstract

Electrodes are transitioning from flexible to stretchable modality to accommodate more complex application scenarios. Here, inspired by the human skin, we report a rapidly formed Janus-structured stretchable (JSS) electrode. Wherein, the phase separation technology enables rapid film formation, and the gravity effect constructs the Janus structure. The Janus structure aggregates liquid metal (LM) on one side and thermoplastic polyurethane (TPU) on the other, providing a combination of highly stretchable and highly conductive nature at the same time. The JSS film has fast film forming time (15 s), metal-like conductivity (10⁶ S/m), high stretchability (260 %), permeable (4077.41 g m⁻² day⁻¹), ultra-thin thickness (50–1000 μm), strain-insensitivity (stretching, folding, and rotation states), as well as excellent cuttable, transferable, recyclable, reconfigurable, and biocompatible property. Furthermore, the JSS films successfully achieve the effective acquisition of physiological, triboelectric, and resistive signals, when applied as standalone devices and integrated electrodes for electrophysiological signal recording, energy harvesting, and wearable sensing. With its prominent performance and broad adaptability, the proposed JSS film is expected to significantly advance the field of stretchable electrodes and further promote the practical applications of flexible and stretchable devices in industrial and electronic skin.