Poly(vinylidene Fluoride)-Based Ferroelectric Polymers for Electromechanical Transduction

Abstract

Poly(vinylidene fluoride) (PVDF) and its derivatives are ferroelectric polymers (FPs) that combine high electric-field-induced strains with mechanical flexibility, light weight, and processability, making them attractive materials for actuator applications. This work reviews the state-of-the-art in PVDF-based electromechanical transduction, covering both reported materials and actuators. Materials are compared by maximum strains, energy densities, and coupling efficiencies and categorized as: 1) vinylidene fluoride (VDF) polymers, including PVDF and its co-, ter-, and tetrapolymers; 2) PVDF-based composites with ceramic, conductive, metal-organic, and organosilicate fillers; and 3) polymer blends with plasticizers or other electroactive polymers. The highest strains and energy densities have been respectively reported for P(VDF-DB) (13.4%) and TiO2/PVDF (11.3 J cm−3) and highest coupling efficiencies for P(VDF-TrFE-CFE-FA), SWCNTs/P(VDF-TrFE), and TiO2/PVDF (0.88). Actuators are compared in terms of maximum displacements and categorized as unimorph and bimorph bending cantilevers, dilating diaphragms, plates, stacks, and tubular structures. Bending cantilevers are the most frequently reported actuators. The highest length-normalized displacements (δ/L) in quasi-static and resonant operation were reported for PVDF bimorphs (0.35 and 0.45 respectively), which can be significantly improved by optimizing the transducer design and employing more efficient materials. The findings further indicate several unexplored transducer material candidates that are anticipated to exhibit high transduction response