33 research outputs found
Ion and Chain Mobility in a Tetrazole Proton-Conducting Polymer
The morphology, relaxation properties,
and conductivity of the statistical copolymer polystyrenic (alkoxy
1<i>H</i>-tetrazole-<i>co</i>-alkoxy nitrile),
an anhydrous proton conductor, were measured. The material phase-separates
into hard and soft domains, the latter corresponding to a phase richer
in the pendant tetrazole groups. Using dielectric and mechanical spectroscopies,
two relaxation processes were observed, the slower associated with
local segmental dynamics of the backbone and the higher-frequency
process involving motion of the tetrazole moieties. The latter is
coupled to the ionic conductivity, which means that below the principal
glass transition of the material (∼313 K) the conductive mechanism
remains active. Thus, the usual compromise in proton exchange membranes
between mechanical stability and ion conductivity can be avoided