Achieving Synergistic Improvement in Dielectric and Energy Storage Properties of All‐Organic Poly(Methyl Methacrylate)‐Based Copolymers Via Establishing Charge Traps

Abstract

How to achieve synergistic improvement of permittivity (εr) and breakdown strength (Eb) is a huge challenge for polymer dielectrics. Here, for the first time, the π‐conjugated comonomer (MHT) can simultaneously promote the εr and Eb of linear poly(methyl methacrylate) (PMMA) copolymers. The PMMA‐based random copolymer films (P(MMA‐co‐MHT)), block copolymer films (PMMA‐b‐PMHT), and PMMA‐based blend films were prepared to investigate the effects of sequential structure, phase separation structure, and modification method on dielectric and energy storage properties of PMMA‐based dielectric films. As a result, the random copolymer P(MMA‐co‐MHT) can achieve a maximum εr of 5.8 at 1 kHz owing to the enhanced orientation polarization and electron polarization. Because electron injection and charge transfer are limited by the strong electrostatic attraction of π‐conjugated benzophenanthrene group analyzed by the density functional theory (DFT), the discharge energy density value of P(MMA‐co‐PMHT) containing 1 mol% MHT units with the efficiency of 80% reaches 15.00 J cm−3 at 872 MV m−1, which is 165% higher than that of pure PMMA. This study provides a simple and effective way to fabricate the high performance of polymer dielectrics via copolymerization with the monomer of P‐type semi‐conductive polymer.