Stretchable Strain Sensors based on Thermoplastic Elastomer Microfluidics Embedded with Liquid Metal

A stretchable capacitive strain sensor based on thermoplastic elastomer (TPE) microfluidics embedded with liquid metal was successfully fabricated. Benefiting from the unique self-bonding feature of the TPE materials, the capacitance of a sensor was enhanced by increasing the number of TPE layers without changing the footprint of the sensor. The change of the sensor capacitance is linearly dependent on the strain with small hysteresis. The gauge factor of the sensor is closed to the theoretical maximum value 1. The capacitance of the sensor is very stable and repeatable after stretching and releasing for 5000 cycles.