Remarks on the Design of Flexible High-Temperature Polymer Dielectrics for Emerging Grand Electrification - Exemplified by Poly(oxa)norbornenes

Polymer dielectrics essentially revolutionized the electrical power system, pervasively used in nearly all the key electronic and electrical devices, due mainly to their suitably large bandgaps. However, insufficient attention has been paid to the bandgap in the design of new polymer dielectrics for high temperatures. In this paper, we present a unified principle for the design of flexible, high temperature polymer dielectrics. As exemplified by our recently discovered poly(oxa)norbornenes (POFNB), saturated bicyclics with varying carbonyl and ether groups in the bicyclic repeat units, connected by unconjugated alkenes and freely rotatable single bonds in conjunction with freely rotating fluorinated benzene ring side-groups, can impart flexibility yet retain thermal stability while providing large bandgaps to olefinic polymers. The results indicate that POFNB has stably low conduction current under concurrent high electric field and elevated temperatures beneficial from its large band gap of ~5 eV and high glass transition temperature of 186 °C.