Flexible pressure sensor based on CNTs/CB/PDMS sponge with porous and microdome structures for sitting posture discrimination

The application fields of flexible pressure sensors are constantly expanding benefiting from their characteristics of being lightweight, flexible, easy to install, etc. Various structures have been developed for the purpose of improving the sensing performances of these sensors. However, the traditional structure designs typically enhance only a single aspect of performance. In this study, a flexible pressure sensor based on carbon nanotubes (CNTs)/carbon black (CB)/polydimethylsiloxane (PDMS) conductive sponge (CCPS) with both porous and microdome dual microstructures is prepared through the double template and swelling ultrasound methods. The introduction of two microstructures leads to the synergistic effect of dual sensing mechanisms, and the dual sensing mechanisms have been discussed according to the changes in microstructure morphology and finite element analysis results. Thanks to the synergistic effect of dual sensing mechanisms, CCPS exhibits comprehensive pressure sensing performances including a wide pressure sensing range of more than 350 kPa, high sensitivity under low pressure (7.10 kPa −1 over 0–25 kPa, 2.96 kPa −1 over 25–135 kPa, 1.09 kPa −1 over 135 kPa), and satisfactory long-term using performance of over 2000 cycles. CCPS is finally demonstrated for applications such as human motion detection, Morse code, and sitting position discrimination, indicating its broad application possibilities.