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Dielectric anisotropy and dielectric relaxation dynamics in chiral and non-chiral salicylaldimine – nematic crystal composites

N. YILMAZ CANLI1,* , Ö. YASA2, C. YÖRÜR2, B. BILGIN ERAN2, F. YAKUPHANOGLU3

Affiliation

  1. Yıldız Technical University, Department of Physics, 34210 Istanbul, Turke
  2. Yıldız Technical University, Department of Chemistry, 34210 Istanbul, Turkey
  3. Fırat University, Department of Physics, 23169 Elazığ, Turkey

Abstract

The dielectric anisotropy and dielectric relaxation dynamics in 4-cyano-4'-pentylbiphenyl and salicylaldimine compounds 5-octyloxy-2-[(4-hexyloxyphenylimino)methyl]phenol (LC1) and (S)-5-octyloxy-2-[{4-(2-methylbutoxy)phenylimino}methyl]phenol (LC2) composites have been investigated. The polarizing microscopy and differential scanning calorimetry results show that salicylaldimine compounds LC1 and LC2 exhibits enantiotropic SmC and SmC* mesophases, respectively. The dielectrical anisotropy of 5CB, 5CB/LC1 and 5CB/LC2 liquid crystals changes from the positive dielectric anisotropy to negative with the frequency of the applied voltage. The critical frequency fc values of dielectrical anisotropy for 4-cyano-4'-pentylbiphenyl and salicylaldimine compounds LC1 and LC2 liquid crystal composites were found to be 693.84, 573.77 and 562.41 kHz, respectively. The dielectric relaxation mechanism of the liquid crystals was analyzed using Cole-Cole plots and the dielectric relaxation mechanism is a non-Debye type relaxation behavior..

Keywords

Liquid crystal, Dielectric anisotropy, Salicylaldimine.

Citation

N. YILMAZ CANLI, Ö. YASA, C. YÖRÜR, B. BILGIN ERAN, F. YAKUPHANOGLU, Dielectric anisotropy and dielectric relaxation dynamics in chiral and non-chiral salicylaldimine – nematic crystal composites, Optoelectronics and Advanced Materials - Rapid Communications, 4, 1, January 2010, pp.86-92 (2010).

Submitted at: Oct. 1, 2009

Accepted at: Jan. 19, 2010