Ionic Conduction and Structural Properties of Organic-Inorganic Composite Based on Poly(propileneglycol)

Correlation between ionic conduction and structural transition of poly(propileneglycol)-silica composite, complexed with lithium salt, was performed by dc and ac electrical measurements, thermal analysis (DSC) and nuclear magnetic resonance spectroscopy in the 200 to 300 K temperature range. At about 285 K an abrupt increase in the dc conductivity and a change of ac conductivity behaviour were observed. Around this temperature it was also observed a linewidth narrowing 7Li NMR while DSC thermograms shows a glass transition Tg immediately followed by a melt point Tm. The dc conductivity-temperature behaviour was explained by the Vogel-Tamman-Fülcher model and ac by the Random Free Energy Barrier Model.