Nacre-inspired tunable strain sensor with synergistic interfacial interaction for sign language interpretation

A highly sensitive and stretchable strain sensor is urgently required in wearable applications. Nevertheless, high sensitivity requiring a significant structural variation even at a subtle deformation and large stretchability related to morphological integrity under a large strain are considered as two contradictory performance indicators of strain sensors. It remains a huge challenge to synchronously acquire high sensitivity and wide detection range. Herein, we prepare a strain sensor with nacre-mimetic structure through spaying Ti-O-C covalent bonding crosslinked MXene/reduced graphene oxide (rGO) (MGO) solution among the multilayer thermoplastic polyurethane (TPU) electrospun mat. The special nacre-mimetic structure and the synergistic motion of different nanosheets endow the MGO/TPU strain sensor (MGTSS) with high sensitivity (GF of 879 within 100% strain, GF of 17782 for a strain of 100%−160%, and 84326 for a strain of 160%−200%), ultra-low detection limit (0.05% strain), large detection range (up to 200% strain), short response time (70 ms) and a favorable sensing stability and durability (5000 stretching/releasing cycles). Moreover, the nacre-mimetic strain sensor can be used for sign language interpretation through monitoring finger gestures, showing great promise for applications in next-generation of wearable flexible electronics devices.