High-sensitivity and ultra-broad linear working region flexible piezoresistive pressure sensors based on PDMS/CNT/TPU

Designing and fabricating flexible piezoresistive pressure sensors (FPPS) with simultaneous high sensitivity and a broad linear working region remains a considerable challenge. In this work, thermoplastic polyurethane (TPU) fiber films were first prepared via electrospinning. Then, the CNTs were anchored onto the surface of a TPU fiber films via ultrasonication as the driving force. Finally, polydimethylsiloxane (PDMS) was used to modify the CNT/TPU and obtain the PDMS/CNT/TPU composite materials. The electrical and mechanical properties of CNT/TPU and PDMS/CNT/TPU were studied. The sensor performances of FPPS based on CNT/TPU and PDMS/CNT/TPU were analyzed and compared. These results prove that the sensitivity of FPPS is significantly improved after the PDMS modification. The optimized PDMS/CNT/TPU FPPS has a sensitivity of 1.43 kPa^-1 in a ultra-broad linear working region of 0-2500 kPa and cycling stability over 6000 cycles. FPPS has been successfully used to monitor physiological signals and human movements, which indicates great potential for wearable electronics and human-machine interfaces.