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2001 (1)
1Author    M. Ohga, F. M. Ostafa, A. Hmed, A. A. YoussefRequires cookie*
 Title    Dielectric Permittivity and AC Conductivity Investigation for the New Model Lipid Bilayer Material: (CH2)io(NH3)2CdCl4  
 Abstract    Differential thermal scanning of the new lipid-like bilayer material (CH2)io(NH3)2CdCl4 showed two structural phase transitions, with onset temperatures at T2 = (359 ± 2) K and 7, = (415± 1) K. Permittiv­ ity measurements were performed between room temperature and 450 K at 60-100 kHz. A step-like rise in permittivity at T2, associated with an order-disorder transition, is attributed to chain melting. Two anomalies at (413 ± 1) K and (430 ± 3) K, showing thermal hysteresis of -8 and 10 K, respectively, in­ dicate first order transitions which are associated with crystalline phase change. The AC conductivity follows an Arrhenius-type relation with the activation energy A£ varying with the frequency / according to the relation AE = A£0 [1 -exp where AE0,f0 and a are 0.95 eV, 52 Hz and 0.11, respectively. The frequency dependent conductivity follows the power law a= C 7dc + ßcov, 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 temperatures lower than 413 K. Variations of B and s with temperature are discussed. PACS No. 76, 77 
  Reference    Z. Naturforsch. 56a, 568—578 (2001); received April 26 2001 
  Published    2001 
  Keywords    Phase Transitions, AC Dielectric Permittivity, Two-dimensional Materials, Lipid Bilayers 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0568.pdf 
 Identifier    ZNA-2001-56a-0568 
 Volume    56