Enhancement of Dielectric Breakdown Strength and Its Possible Mechanism in Triple-Layered Films Formed by Stacking Resin Layers with Different Relative Dielectric Constants

• Published in: Bulletin of the Chemical Society of Japan Vol. 95; no. 11; pp. 1620 - 1625
• Main Authors: Inagaki, Yumi, Kozawa, Takahiro, Yano, Kazuhisa, Nakamura, Tadashi
• Format: Journal Article
• Language: English
• Published: Tokyo The Chemical Society of Japan 15.11.2022; Chemical Society of Japan
• Subjects: Dielectric breakdown; Dielectric properties; Dielectric strength; Permittivity; Polymethyl methacrylate; Polyvinylidene fluorides; Polyvinylidene fluoride; Dielectric breakdown; Triple-layered film
• DOI: 10.1246/bcsj.20220240
• ISSN: 0009-2673

Dielectric properties of co-extruded triple-layered films consisting of polymethyl methacrylate (PMMA) sandwiched between polyvinylidene fluoride (PVDF) layers were evaluated. The triple-layered films showed a higher dielectric breakdown strength and a higher energy density than each single-layer film, and the enhancement depended on the volume ratio of the PMMA layer, which has a lower relative dielectric constant than PVDF. The simulation of dielectric breakdown paths using the phase-field model revealed that the middle layer with a lower dielectric constant shares a higher voltage until its dielectric breakdown, resulting in an enhancement of the dielectric breakdown strength in the triple-layered film. The simulation results well matched the experimental data, indicating that controlling the volume ratio and relative dielectric constant of each layer in the triple-layered film is an effective approach to enhancing dielectric breakdown strength. This concept is considered promising for developing dielectric materials that enable a size reduction of film capacitors.