Ion-Conducting Polymers - Quenched to Dynamic Disorder

TL;DR

This paper investigates ion-conducting polymers, revealing how their structure transitions from quenched to dynamic disorder regimes depending on salt concentration, affecting diffusivity and morphology.

Contribution

It demonstrates the crossover from quenched to dynamic disorder in ion-conducting polymers and links structural changes to ion diffusivity behavior.

Findings

Low salt fraction exhibits quenched disorder with diffusivity related to crystallinity.

High salt fraction shows dynamic disorder with rapid polymer chain rearrangements.

Morphological transition from DLA-type to polygonal spherulites with increasing salt.

Abstract

Ion conducting polymers have a biphasic character with crystalline as well as amorphous phases. There is moreover, a dynamic disorder due to motion of polymer chain segments. The PEO-NH$_4$ClO$_4$ system undergoes a crossover from a DLA-type morphology for low salt fraction (X) to a structure with polygonal spherulites. In the present communication we show that the low X regime exhibits a variation of diffusivity with crystallinity typical of a quenched system, whereas the high X regime has dynamic disorder with rapid rearrangement.