Optimizing nanostructure to achieve high dielectric response with low loss in strongly dipolar polymers

Abstract

Advances in modern electronics require the development of polymer-based dielectric materials with high dielectric constant, low dielectric loss, and high thermal stability. Fundamental dielectric theory suggests that strongly dipolar polymers have the potential to realize a high dielect Q3 ric constant. In order to achieve high thermal stability, these polymers should also possess a high glass transition temperature T g . However, it has been observed that in many dielectric polymers the dielectric constant decreases markedly at temperatures below T g due to dipole freezing. This study shows, through combined theoretical and experimental investigations, that nano-structure engineering of a weakly-coupled strongly-dipolar polymer can result in a high energy density polymer with low loss and high operating temperature. Our studies reveal that disorder creates a significantly larger free volume at temperatures far below T g , enabling easier reorientation of dipoles in response to an electric field in aromatic urea and thiourea polymers. The net result is a substantial enhancement in the dielectric constant while preserving low dielectric loss and very high breakdown field. These results here pave the way 1 3 5 7 Please cite this article as: Y. Thakur, et al., Optimizing nanostructure to achieve high dielectric response with low loss in strongly dipolar polymers, Nano Energy (2015), http://dx.doi.org/10.1016/j.nanoen.2015.06.021for engineering the nanostructure to create high energy density polymers with low loss and high operating temperature.

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