Flexible Paper-Based Piezoresistive Sensors Based on Aramid Nanofibers and Carbon Nanotubes

In the field of flexible sensing, developing composite paper-based sensors with high mechanical strength and high resistance responsiveness is a challenge. In this study, a strategy for aramid nanofiber (ANF)/carbon nanotube (CNT) composite paper-based piezoresistive sensors is proposed. By introducing the OP-10 surfactant-assisted grinding process, the dispersibility of CNTs is effectively improved, and their structural integrity is protected. The excellent electrical properties of CNTs, combined with the porous framework and controllable deformation capability of ANFs, construct a flexible sensing material with a piezoresistive response, which can monitor external pressure stimuli. The research shows that when the mass fraction of ANFs is optimized to 25 wt %, the electrical conductivity of the composite paper reaches a maximum of 1135.1 S/m, and the sheet resistance drops to 23.5 Ω/sq., indicating that its conductive network achieves the best synergistic state. The sensor exhibits excellent sensitivity over a wide pressure range (with a maximum sensitivity of 0.0304 kPa–1). It also has fast response and recovery times (320 and 230 ms, respectively) and shows excellent stability and durability during cyclic loading (withstanding more than 6000 compression cycles). In addition, the ANF/CNT flexible paper-based piezoresistive sensor can monitor human motion and the bending of composite components and has important application potential in fields such as electronic skin, wearable intelligent health monitoring devices, and human-computer interaction.