Extracellular Matrix Inspired Molecular Polarization in Hydroxypropyl-β-Cyclodextrin Organic Dielectric Films

Inspired by the extracellular matrix (ECM), which integrates a fibrous collagen scaffold with a hydrated polysaccharide matrix, we developed a PVDF-based ternary dielectric energy storage film by introducing hydroxypropyl-β-cyclodextrin (HP-β-CD) within a fluorinated methacrylate crosslinked network. The crosslinked network serves as a compact insulating scaffold analogous to collagen fibers, while HP-β-CD mimics the hydrated polysaccharide components. The abundant hydroxyl groups of HP-β-CD form stable hydrogen bonds with PVDF chains, strengthening interfacial adhesion and tuning local chain conformation. Under an external electric field, the polar hydroxyl and hydroxypropyl groups of HP-β-CD contribute to orientational polarization, increasing the dielectric constant to 9.7. In addition, the hydroxyl-rich exterior and cavity-bearing structure of HP-β-CD may provide charge-trapping sites that help suppress charge accumulation and conduction losses, thereby retarding electrical breakdown. The fluorinated crosslinked network enhances breakdown strength by restricting PVDF segmental motion and improving film compactness and structural stability. Consequently, the leakage current density decreases to 5.25 × 10-7 A/cm2, approximately one order of magnitude lower than that of neat PVDF (2.02 × 10-6 A/cm2). Benefiting from this ECM-inspired molecular-regulation approach, the optimized composite achieves a discharged energy density of 9.03 J/cm3 at 560 MV/m, while the residual PVDF-related hysteresis indicates that further efficiency optimization remains necessary for practical high-efficiency capacitor applications.