Dielectric Response of Large Band Gap Cyclic Olefines With Symmetric and Asymmetric Pendant Polar Groups

ABSTRACT The dielectric response of two typical polyoxafluoronorbornene with asymmetric and symmetric pendant polar groups is investigated to better understand the impact of the polymer structure on dielectric properties. Based on the Dissado–Hill modelling of broadband dielectric response, the contribution of the bicyclic backbone and fluorinated pendant groups to the dielectric response processes are decomposed. The characteristic frequency of γ‐relaxation in polyoxafluoronorbornene is found to be far beyond the regular operation conditions. Thus, it can be utilised for the enhancement of permittivity for higher energy density. It is found that the rotation of the pendant benzene ring (β‐relaxation) plays a significant role in determining the permittivity and loss. An asymmetric structure is effective in enhancing the permittivity, while a prominent decrease of loss can be achieved with the symmetric structure. Therefore, it should be kept in mind to suppress the dielectric loss when enhancing the dielectric constant as well as energy storage density via β‐relaxation.