Realization of flexible pressure sensor based on conductive polymer composite via using electrical impedance tomography

Efficient and accurate detection of pressure applied on diverse surfaces is essential for pressure sensors. In this paper, a flexible pressure sensor based on thermoplastic polyurethanes (TPU)-carbon black (CB) conductive composite and electrical impedance tomography (EIT) is introduced. The conductivity of the composite is sensitive and linearly responsive to external pressure signal, which is feasible for reconstructing pressure distribution by using EIT technique that measures voltage on the boundary of the composite and then reconstructs conductivity changes in the composite. The pressure sensor is fabricated by screen printing TPU-CB composite and Ag electrode layer on flexible Polyethylene terephthalate (PET) sheet, which shows excellent portability and full flexibility. Meanwhile, it requires few sensing units and internal transmission wires, beneficial for nondestructive measurement towards targets. We successfully use the pressure sensor to estimate the location and value of pressure applied on single or multiple regions, and further detect daily objects for practical applications, demonstrating the sensing ability of the pressure sensor. Our sensor has bright prospect in the fields of bionic skin in intelligent robots, wearable electrical devices, motion monitoring systems and touch-control instruments.