Abstract: The conductive polymer poly(3,4-thylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits potential in the development of flexible devices due to its unique conjugated structure and water-solubility characteristics. To address the incompressibility of the original PEDOT:PSS aerogel without compromising its high conductivity, a stable interpenetrating polymer network (IPN) was self-assembled by guiding the molecular motion within PEDOT:PSS and introducing multi-walled carbon nanotubes (MWCNTs). By combining critical surface removal, directional freeze-drying, and polydimethylsiloxane (PDMS) reinforcement processes, a hydrophobic PDMS@MWCNTs/PP aerogel with a highly oriented porous structure and high strength was prepared. Under the synergistic effect of MWCNTs/PEDOT:PSS electroactive scaffold, the composite aerogel exhibited a high sensitivity of up to 16.603 kPa^-1 at 0-2 kPa, a fast response time of 74 ms, and excellent repeatability. Moreover, the sensor possessed hydrophobicity with a good water contact angle of 137° The sensor could serve as a wearable electronic monitoring device to achieve accurate and sensitive detection of human motion including large-scale human activities and tiny muscle movements. Therefore, our findings provide a new direction to fabricate high-performance piezoresistive sensors based on three-dimensional (3D) conductive polymer active scaffolds, demonstrating their great potential for flexible electronics, human-computer interaction, and a wide range of applications under special working conditions.

Key words: Pressure sensor, PEDOT:PSS/MWCNTs hydrogel, Composite aerogel, Hierarchical porous structure, Human motion detection