Highly sensitive and stretchable strain sensor based on self-aligned and periodic cracking of wavy metal nanowire/elastomer composite film

Abstract

In this work, we present a new class of stretchable strain sensor employing a wavy metal nanowire (mNW)/elastomer composite film. Stretching-induced strain is predominantly concentrated in the valley regions of the wavy composite film following thermal annealing, and self-aligned and periodic mechanical cracks are induced by the strain concentration effect therein. The strain-dependent opening-and-closing process of the cracks supported by the mNW percolation network allows the sensor to exhibit large stretchability (160%) and high mechanosensitivity (gauge factor ≈874.1 at 110%–160% strain) simultaneously. Significant hysteresis is not observed, even when subjected to repeated stretching cycles. The wavy strain sensor is also demonstrated as a motion detector to recognize finger joint motions of a wooden hand model in real time.