A self-healing substrate for liquid-metal based wearable sensor

Rapid development and evolution are needed in the era of information human wearable sensors for the data collection basis of the Internet of Things. To deal with the issues of poor flexibility in the existing sensing schemes, as well as the inability of devices to self-heal, we synthesized a silicone self-healing material-PP3, which could serve as a flexible substrate for wearable sensors. The fracture stress of this material is 0.34 MPa, with a record elongation at break of up to 290%; its self-healing efficiency can reach more than 80% after 12 h of repair at room temperature. We printed liquid metal based on gallium as the flexible circuit over the PP3 substrate by modifying the surface of the substrate. Here, based on the self-healing property of PP3 and the fluidity of liquid metal, we realize triboelectric sensors with overall self-healing capability able to monitor pressure in the range of 5180 kPa; their maximum sensitivity reaches 0.9/kPa under low pressure, and good stability is maintained for the triboelectric sensors after 400-cycle tests.