Silver nanosheets doped polyvinyl alcohol hydrogel piezoresistive bifunctional sensor with a wide range and high resolution for human motion detection

The soft pressure sensor is a very important element in flexible wearable devices. Its advantage is that it can adapt to curves and deformed surfaces, and it is widely used in wearable devices to monitor behavior and in other fields. In this work, we successfully prepared a conductive hydrogel with good tensile and compression properties by mixing silver nanosheets (AgNSs) into the matrix of polyvinyl alcohol (PVA) hydrogel. The hydrogel sensor shows high sensitivity and rapid response under low pressure, with a sensitivity of 10.76 kPa−1 in 0–5 kPa and a response time of 197 ms under 40% compression. Because of its fast and sensitive response to light signal modulation, gesture change, wrist bending, radial artery signal, speech vibration, and stomping, the hydrogels can be used as a pressure and tension bifunctional sensor in wearable devices to monitor human behavior.