Performance Optimization and Bending Stability Study of Flexible Pressure Sensors Based on Graphene/PDMS Composite Film

The escalating demand for flexible pressure sensors in domains such as health monitoring, human-machine interfaces, and intelligent robotics highlights the imperative for elevating the sensitivity and stability benchmarks, particularly under bending operational conditions. Nevertheless, current studies mainly focus on improving sensor sensitivity and broadening detection range, with a notable overlook of research on their operational stability in bending work scenarios. Here, we construct a low-cost resistive-type flexible pressure sensor by fabricating a graphene/polydimethylsiloxane (PDMS) composite film with a microstructured surface. The impact of filler concentration, composite film microstructure, and thickness of the pressure-sensitive layer on the pressure-resistive characteristics and operational stability under various bending conditions is thoroughly investigated. Our findings reveal that the I–V characteristics of the flexible pressure sensor are mainly affected by the graphene particle distribution, microstructural properties, and the extent of resistance variation within the pressure-sensitive layer, while the operational stability under bending stress is contingent upon factors including the film’s Young’s modulus, hardness, pressure distribution during bending, and internal interactions within the film. This work offers profound insights into the design of flexible pressure sensors with high sensitivity and bending stability compatibility for real-world applications.