Ion dynamics in solid polyelectrolyte materials.

Cramer C, Akgoel Y, Imre A, Bhide A, Schoenhoff M

Abstract

Frequency-dependent conductivities are a valuable tool for studying the ion dynamics on different time scales. We present and analyze cond. spectra of two kinds of solid polyelectrolyte materials, viz. polyelectrolyte multilayers (PEM) and polyelectrolyte complexes (PEC). The PEM spectra are taken as a function of relative humidity at ambient temp. By contrast, the cond. of different kinds of dried PEC is studied as a function of temp. For both kinds of material classes we show that the MIGRATION concept developed by Funke and co-workers can be used to describe the exptl. spectra over wide ranges in frequency, indicating that forward-backward hopping motions of small ions play a vital role in solid polyelectrolyte materials. Apart from these potentially successful hops, localized motions of charged particles are found to influence the cond. spectra as well. Based on the shape of our cond. spectra and their scaling properties, we arrive at important conclusions about the microscopic ion dynamics in PEM and PEC materials. [on SciFinder(R)]