Study of flexible piezoresistive sensors based on the hierarchical porous structure CNT /PDMS composite materials

Flexible piezoresistive sensors (FPS) are important components of wearable electronics for human-machine interaction, human physiological signal monitoring and electronic skin. In this work, carbon nanotube (CNT)-polydimethylsiloxane (PDMS) (abbreviated as CP) composite materials with hierarchical porous structures were prepared by a facile solvothermal method. The electrical conductivity and mechanical elasticity of the porous structure CP composite materials can be separately tuned by varying the CNT mass fraction and PDMS composition ratio, respectively. A flexible piezoresistive sensor using porous structure CP composite materials as the sensing material was designed and fabricated. The optimized sensor exhibits a sensitivity of 0.59 kPa−1 in the pressure ranges of 0–260 kPa, a low detection limit of 12 Pa, a fast response time of 25 ms and outstanding cycling stability over 1,700 cycles. Such sensor design can be integrated into flexible wearable electronic devices for physiological signal monitoring in real-time.