Study of Optical and Dielectrical Properties in a Homologous Series of Bent Liquid Crystals Formed by Self Assembly Systems

Author: Prabu N. Pongali Sathya   Vijayakumar V. N.   Madhu Mohan M. L. N.  

Publisher: Taylor & Francis Ltd

ISSN: 0015-0193

Source: Ferroelectrics, Vol.425, Iss.1, 2011-01, pp. : 114-128

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Abstract

Self assembly systems formed by resorcinol and alkyloxy benzoic acids are isolated. Resorcinol formed double hydrogen bonds with p-n- alkyloxy benzoic acids with a bent structure. Various hydrogen bonded complexes have been synthesized with resorcinol from pentyloxy to dodecyloxy benzoic acids respectively. Fourier Transform Infrared Spectra (FTIR) studies confirm the hydrogen bond formation in the complexes. Polarizing Optical Microscopic (POM) studies revealed the textural information while the transition and enthalpy values are experimentally deduced from Differential Scanning Calorimetry (DSC) studies. Phase diagram has been constructed from the POM and DSC data respectively. Variation of helicoidal structure with temperature in smectic C phase of the homologous series have been recorded and analyzed. Dielectric relaxations in smectic C phase of the complexes indicate a Cole-Cole relaxation process and the activation energies have been calculated. An interesting observation is the occurrence of an anomalous dielectric relaxation behavior in some of the complexes which has been discussed.