Flexible Piezoelectric Sensor Based on Two-Dimensional Topological Network of PVDF/DA Composite Nanofiber Membrane

Owing to the robust scalability, ease of control and substantial industrial applications, the utilization of electrospinning technology to produce piezoelectric nanofiber materials demonstrates a significant potential in the development of wearable products including flexible wearable sensors. However, it is unfortunate that the attainment of high-performance piezoelectric materials through this method remains a challenging task. Herein, a high-performance composite nanofiber membrane with a coherent and uniformly dispersed two-dimensional network topology composed of polyvinylidene fluoride (PVDF)/dopamine (DA) nanofiber membranes and ultrafine PVDF/DA nanofibers was successfully fabricated by the electrospinning technique. Based on the evidence obtained from simulations, experimental and theoretical results, it was confirmed that the unique structure of the nanofiber membrane significantly enhances the piezoelectric performance. The present PVDF/DA composite nanofibers demonstrated a remarkable piezoelectric performance such as a wide response range (1.5–40 N), high sensitivity to weak forces (0–4 N, 7.29 V N⁻¹), and outstanding operational durability. Furthermore, the potential application of the present PVDF/DA membrane as a flexible wearable sensor for monitoring human motion and subtle physiological signals has also been validated. This work not only introduces a novel strategy for the application of electrospun nanofibers in sensors but also provides new insights into high-performance piezoelectric materials.