Geometrical and electrical modulation of cracked metal films based on metal nanowire/elastomer composites for high-performance wearable strain sensing

Abstract

This work presents a simple yet highly efficient strategy to geometrically and electrically modulate mechanical cracks in a thin metal film for the fabrication of high-performance stretchable strain sensors. This is accomplished using a silver nanowire (AgNW)/dragon skin (DS) composite with a customizable surface structure. The AgNW/DS composite layer formed between a platinum (Pt) film and elastomeric DS substrate plays a vital role in redistributing the surface strain upon stretching, leading to a unique crack morphology comprising network-shaped Pt cracks coupled with conductive AgNW bridges. The Pt/AgNW/DS (PAD) strain sensor exhibits balanced sensing performance with large stretchability (75%), high sensitivity (maximum gauge factor of ∼493.2), negligible hysteresis and drift characteristics, fast response (∼205 ms), and long-term durability (1000 cycles at 30%). Finally, the PAD sensor is successfully demonstrated as a wearable device that can detect strains caused by various human activities and the volumetric change in a balloon in real time.