Dual-active-layer flexible piezoresistive sensor based on wrinkled microstructures and electrospun fiber network for human-related motion sensing applications

Flexible pressure sensors with high sensitivity and a wide detection range must be developed for practical applications. In this study, a dual-active-layer flexible piezoresistive sensor was developed. A reduced graphene oxide film with wrinkled microstructures was prepared by a simple and low-cost substrate pre-stretching method and used as the first active layer. A thermoplastic polyurethane electrospun fiber membrane was modified by fast polydopamine coating and ultrasonication with multi-walled carbon nanotubes and used as the second active layer. Owing to the continuously changing conductive pathways created by the wrinkled microstructures and fiber network under pressure deformation, the sensor achieved a detection range of 0–100 kPa, with sensitivities of 8.5, 1.35, and 0.39 kPa −1 in the ranges of 0–1, 1–20, and 20–100 kPa, respectively. Additionally, the sensor exhibited a low detection limit (2 Pa), response and recovery times of 105 and 85 ms, respectively, and reliable service performance over 10,000 loading/unloading cycles. The sensor enabled real-time monitoring of finger and wrist bending, beaker-holding, and fingertip-sliding on a touch screen, demonstrating its feasible applications in wearable electronics and human–machine interface devices.