Highly stretchable, sensitive and healable polyurethane-urea/graphene nanocomposite sensor for multifunctional applications

Flexible wearable electronic devices offer promising potential for monitoring physiological signals. However, creating a single sensor that integrates high tensile strength, sensitivity, self-healing capabilities and a wide working range presents a significant and multifaceted challenge. This study reports a novel nanocomposite consisting of polyurethane-urea elastomer (PUU) and graphene nanoplatelets (E-GNPs) that are mechanochemically modified with diethyltoluene diamine ethacure 100. A low electrical percolation threshold was observed at 4.17 vol% E-GNPs. The sensor based on the PUU nanocomposite at 7 vol% of E-GNPs has revealed a gauge factor up to 17.57 and a wide working range of 361.76 % with high tensile strength of 19.73 MPa. It can withstand 20,000 cycles at 50 % strain. The sensor exhibits negative temperature dependence at 20-100 °C, with a resolution of 0.01/°C at 36-40 °C. Treatments with solvents and heat enable a healing efficiency for sensitivity of up to 70.46 %. The healable sensor enables real-time monitoring of temperature and strain signals, making it ideal for wearable devices in human health and sports monitoring.