(412e) Fabrication of P(VDF-TrFE-CFE) Electrocaloric Thin Film Using Electrospray Processing

Solid-state cooling using electrocaloric (EC) materials has gained significant attention due to their potential to increase heat pump efficiency and to serve as a replacement for vapor compression cycles used in heating, venting, and air conditioning (HVAC) systems. The EC effect is an adiabatic, reversible temperature process that happens in EC materials under an external electric field. Among all the energy materials used in EC research, poly(vinylidene fluoride-trifluoroethylene-chlorofluoroentylene) (PVDF-TrFE-CFE) holds great promise as a next-generation energy material for EC cooling because of its unique combination of a giant EC temperature change, lead-free composition, high energy efficiency, good thermal stability, and reliability. Therefore, the demand for polymer thin films in practical applications has risen, and an effective thin film fabrication method is needed. In this study, the properties and performance of PVDF-TrFE-CFE films prepared by solution casting (SC) and electrospray (ES) processing are characterized. ES processing, the precisely-controlled, layer-by-layer deposition of polymer with rapid solvent evaporation, is an established method for polymer processing, but this method has not yet been used to generate EC materials. It was found that the ES films had more uniform film thicknesses and fewer defects on the surface compared with SC films In addition, a post-annealing treatment on both ES and SC thin films altered the degree of crystallinity and crystallite size, which has the potential to improve the EC effect of the polymer films. Furthermore, an enhancement dielectric properties was also identified in the ES films. The outcomes suggest that the polymer films prepared through ES processing have a greater performance in terms of film surface quality, crystallinity, and energy storage capabilities compared with those produced via solution casting. With a high potential for scalability and future manufacturing, the electrospray technique presents an approach to thin film fabrication for new electrocaloric materials.