Fabrication and Performance Study of 3D-Printed MWCNTs/PDMS Flexible Piezoresistive Pressure Sensors

Piezoresistive pressure sensing has broad application prospects in wearable fields such as human–machine interaction, physiological signal detection, and electronic skin. As a high-performance conductive filler, multi-walled carbon nanotubes (MWCNTs) have demonstrated extensive application potential across various domains. However, polymer composites filled with MWCNTs exhibit complex behavior during the printing process, which increases the difficulty of applying extrusion-based 3D printing technology. To this end, this study systematically investigated the extrusion 3D printing process of MWCNTs/polydimethylsiloxane (PDMS) composites. In this research, MWCNTs/PDMS composites with MWCNTs mass fractions of 1 wt%, 2 wt%, 3 wt%, and 4 wt% were prepared. The printability of the materials at each ratio was systematically explored, and rational printing process parameters were determined. On this basis, the influence of MWCNTs mass fraction on sensor performance was analyzed through tensile testing. Finally, three sets of experiments, including palm gesture recognition and gripping tests, elbow joint motion monitoring, and continuous pressure monitoring, successfully verified the feasibility of the fabricated sensors in human motion monitoring. The results demonstrate that the sensors made of this composite material via extrusion 3D printing possess excellent application potential in the field of flexible wearable electronics.