Fluoro-Polymer@BaTiO₃ Hybrid Nanoparticles Prepared via RAFT Polymerization: Toward Ferroelectric Polymer Nanocomposites with High Dielectric Constant and Low Dielectric Loss for Energy Storage Application

TLDR

Polymer nanocomposites with high energy density and low dielectric loss are highly desirable, yet the role of the polymer–nanoparticle interface in achieving these properties remains poorly understood. The study proposes a novel strategy to enhance the interface between BaTiO₃ nanoparticles and poly(vinylidene fluoride‑co‑hexafluoropropylene) ferroelectric polymer. Core–shell BaTiO₃ nanoparticles were synthesized by surface‑initiated RAFT polymerization of fluoroalkyl acrylates, and their dielectric behavior and energy‑storage performance were characterized using broadband dielectric spectroscopy and D–E loop measurements. The resulting nanocomposites achieved high energy density with low dielectric loss, and their storage densities could be tuned by modifying the fluoro‑polymer shell, demonstrating a versatile route for high‑performance polymer nanocomposites.

Abstract

Polymer nanocomposites with high energy density and low dielectric loss are highly desirable in electronic and electric industry. Achieving the ability to tailor the interface between polymer and nanoparticle is the key issue to realize desirable dielectric properties and high energy density in the nanocomposites. However, the understanding of the role of interface on the dielectric properties and energy density of polymer nanocomposites is still very poor. In this work, we report a novel strategy to improve the interface between the high dielectric constant nanoparticles (i.e., BaTiO3) and ferroelectric polymer [i.e., poly(vinylidene fluoride-co-hexafluoro propylene)]. Core–shell structured BaTiO3 nanoparticles either with different shell thickness or with different molecular structure of the shell were prepared by grafting two types of fluoroalkyl acrylate monomers via surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization. The dielectric properties and energy storage capability of the corresponding nanocomposites were investigated by broadband dielectric spectroscopy and electric displacement-electric field loop measurement, respectively. The results show that high energy density and low dielectric loss are successfully realized in the nanocomposites. Moreover, the energy storage densities of the P(VDF-HFP)-based nanocomposites could be tailored by adjusting the structure and thickness of the fluoro-polymer shell. The approach described is applicable to a wide range of nanoparticles and polymer matrix, thereby providing a new route for preparing polymer-based nanocomposites used in electronic and electric industry.