A flexible piezoresistive pressure sensor comprising a microstructure printed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) copolymers@graphene hybrid ink

Abstract

Piezoresistive pressure sensors have attracted significant attention because of their application prospects in a wide range of fields, including wearable electronics, electronic skin, and robotics. In pressure testing, the material and internal structure of piezoresistive pressure sensors affect their performance. Therefore, the primary focus of this research was to evaluate the use of graphene (Gr)-incorporated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) ink for printing microstructures on flexible substrates to fabricate small piezoresistive sensing composite structures. The effect of graphene on the resulting microstructure was investigated, revealing an increase in conductivity under the same pressure. Experiments showed that incorporating graphene at 0.75 wt% and controlling the microstructure (height of 35 μm and electrode spacing of 200 μm) improved the sensitivity of the designed sensor, which exhibited a sensitivity of 0.49 kPa⁻¹, a fast response time of 42 ms, and good durability. Moreover, the sensor performed well in the detection of physiological signals, such as the human pulse and joint flexion. Therefore, it has potential application value in human health monitoring.