Andreas Killis

Correlation among transport properties in ionically conducting cross-linked networks

Abstract Examination of the quantitative correlation between the ionic conductivity and the dynamic mechanical properties of cross-linked polyether networks filled with an inorganic salt supports the assumption that mobile ions and chains segments need the same free volume fraction for their diffusion. The spin-spin relaxation time of the different nuclei belonging either to the macromolecular chains or to the ionic species exhibits the same free volume dependence. From the study of the conductivity variations with respect to salt concentration it is concluded that its dissociation is probably complete even at relatively high concentration.

Correlation between ionic conductivity and7Li-NMR of polyether-polyurethane networks containing lithium perchlorate

SummaryThe effect of temperature on the ionic conductivity and the7Li NME line width of a polyether-polyurethane network containing lithium perchlorate was studied. A treatment of the results based on free-volume principles yielded a linear correlation between the logarithm of the reduced conductivity, бT /бT0, and the logarithm of the reduced7Li NMR line width, δT/δT0, for a given reference temperature, To=323 K.

Mechanism of high ionic conductivity in elastomeric networks

Abstract The viscoelastic properties and the ionic conductivity of polyether-polyurethane networks containing alkali metal salts have been studied at various temperatures, salt concentrations and network structures. The reduced temperature, TT g , is the predominant parameter which governs the viscoelastic behaviour and the ionic conductivity of these networks. Using the free volume concept an expresssion is derived for the ionic conductivity, irrespective of the macrostructure involved. The logarithm of the reduced conductivity, σ T /σ T R (which is the ratio of the conductivity at a given temperature to that at the reference temperature), is a linear function of the shift factor, log a T , given by the dynamic mechanical properties. A comparison is made between the WLF parameters C 1 and C 2 , obtained from conductivity and viscoelastic measurements.