Morphology of Hydrated As-Cast Nafion Revealed through Cryo Electron Tomography

Morphology of Hydrated As-Cast Nafion Revealed through Cryo Electron Tomography

TitleMorphology of Hydrated As-Cast Nafion Revealed through Cryo Electron Tomography
Publication TypeJournal Article
Year of Publication2015
AuthorsFrances I Allen, Luis R Comolli, Ahmet Kusoglu, Miguel A Modestino, Andrew M Minor, Adam Z Weber
JournalACS Macro Letters
Volume4
Issue1
Pagination1 - 5
Date Published01/2015
ISSN2161-1653
Abstract

Nafion is an ion-containing random copolymer used as a solid electrolyte in many electrochemical applications thanks to its remarkable ionic conductivity and mechanical stability. Understanding the mechanism of ion transport in Nafion, which depends strongly on hydration, therefore requires a complete picture of its morphology in dry and hydrated form. Here we report on a nanoscale study of dry versus hydrated as-cast 100 nm Nafion membranes using analytical transmission electron microscopy (TEM) and cryogenic TEM tomography, respectively. For the dry membrane, spherical clusters ?3.5 nm in diameter corresponding to the hydrophilic sulfonic-acid-containing phase are identified. In contrast, cryo TEM tomography of the hydrated membrane reveals an interconnected channel-type network, with a domain spacing of ?5 nm, and presents the first nanoscale 3D views of the internal structure of hydrated Nafion obtained by a direct-imaging approach.

DOI10.1021/mz500606h