Solution-processed linear methyl methacrylate-co-glycidyl methacrylate films with excellent dielectric and energy storage characters

Abstract

Research on linear dielectric glass polymer films with high permittivity and low loss has attracted much attention recently. In the present report, a series of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) copolymers (MG) with different MMA/GMA ratios were synthesized by a continuous solution polymerization and devolatilization extrusion method and their corresponding MG dielectric films were prepared via a solution-processed method. Different from the pristine poly MMA (PMMA) film, the introduction of GMA endowed higher polarity and provided deep traps. Consequently, the MG films demonstrated higher permittivity (5.5–7.0, 100 Hz) and lower loss than the pristine PMMA films. Moreover, the improved Young's modulus and low dielectric/conductive loss led to a higher Weibull breakdown strength of the MG films (450–530 MV m⁻¹). The excellent dielectric performance and breakdown resistance allowed achieving superior energy storage properties for the MG dielectric films. In particular, the discharged energy density and charge–discharge efficiency reached 6.81 J cm⁻³ and 84.1% at 500 MV m⁻¹ for the MG 8 film. Therefore, this research provides a new dielectric polymer material with good cost performance, which displays potential application prospects in the thin-film capacitor field.