Dielectric permittivity and AC conductivity investigation for the new model lipid bilayer material: (CH2)(10)(NH3)(2)CdCl4

Differential thermal scanning of the new lipid-like bilayer material (CH2)( 10)(NH3)(2)CdCl4 showed two structural phase transitions, with onset temper atures at T-2 = (359 +/- 2) K and T-1 = (415 +/- 1) K. Permittivity measure ments were performed between room temperature and 450 K at 60-100 kHz. A st ep-like rise in permittivity at T2, associated with an order-disorder trans ition, is attributed to chain melting. Two anomalies at (413 +/- 1) K and ( 430 +/- 3) K, showing thermal hysteresis of similar to 8 and 10 K, respecti vely, indicate first order transitions which are associated with crystallin e phase change. The AC conductivity follows an Arrhenius-type relation with the activation energy AE varying with the frequency f according to the relation DeltaE = D eltaE(0) [1 - exp (f(0)/f)](alpha), where DeltaE(0), f(0) and alpha are 0.9 5 eV, 52 Hz and 0.11, respectively. The frequency dependent conductivity fo llows the power law sigma = sigma (de) + B omega (x) with 0.3 <s < 1.5 for hopping conduction of hydrogen and/or chloride ions in the high temperature range, and localized hopping and/or orientational motion predominating tem peratures lower than 413 K. Variations of B and s with temperature are disc ussed.