All-organic polymer dielectrics prepared via optimization of sequential structure of polystyrene-based copolymers

It is a great challenge to improve simultaneously the permittivity (epsilon(r)) and breakdown strength of polymer dielectrics. The linear polystyrene (PS) has the advantages of low cost, easy processing and high charge-discharge efficiency (eta). However, the low epsilon(r) and low breakdown strength result in the low discharge energy density (U-e) of PS. For polar liquid crystalline polymer poly[11-((4'-cyano-[1,1'-biphenyl]-4-yl)oxy)undecyl methacrylate] (PCBMA), it shows the merit of high epsilon(r), low band gap width and good film-forming property. In this paper, random copolymers P(St-co-CBMA) and block copolymers PS-b-PCBMA were synthesized by radical polymerization and reversible addition-breaking chain transfer polymerization, respectively. The effect of sequential structure on the dielectric behaviors and energy storage properties of polystyrene copolymers is investigated in detail. The experimental results indicate that a high epsilon(r) value of 5.2 (+/- 0.049), an outstanding U-e of 8.94 J/cm(3) and high eta of 87.4% at 476 MV/m are achieved in random copolymer P(St-co-CBMA) with the 92 mol% content of CBMA unit because of the strong orientation polarization, deep traps and good film-forming property. This work demonstrates that it is a feasible strategy to obtain high performance polystyrene copolymer dielectrics via tailoring sequential structure between functional monomer and styrene monomer.

Automated summary

This study investigates the influence of sequential structure on the dielectric and energy storage properties of polystyrene copolymers. By tailoring the sequential structure between functional monomer and styrene monomer, polystyrene copolymer dielectrics with high permittivity and energy storage performance can be obtained.