Leaf vein-inspired ethyl cellulose mediated dual-network design for enhanced energy storage in PVDF-based all-organic polymer dielectrics

Abstract

High dielectric loss and relaxation loss restrict the applications of ferroelectric crystalline polymers such as polyvinylidene fluoride (PVDF) in modern electronic systems. Inspired by the supporting structure of leaf veins, flexible all-organic dielectric films were fabricated by incorporating hexafluorobutyl acrylate (HFBA) and ethyl cellulose (EC) into PVDF via solution casting and in-situ ultraviolet (UV) polymerization. Three-dimensional (3D) molecular interpenetrating network from HFBA polymerization and the hydrogen-bond crosslinking network from EC synergistically optimize the film microstructure. The confinement of PVDF chain motion and the trapping of charge carriers effectively reduce dielectric loss and leakage current density. The dielectric loss decreases from 0.0623 for PVDF to 0.0171, and the leakage current density drops from 4.45 × 10⁻⁶ A/cm² to 3.21 × 10⁻⁷ A/cm², over one order of magnitude lower. A maximum energy storage density of 7.74 J/cm³ is achieved, 2.31 times that of pure PVDF (3.35 J/cm³). This work provides a promising strategy for the scalable preparation and application of high-performance flexible dielectrics.