• Dielectric properties of 4′-n-alkyl-4-cyanobiphenyls in their nematic phases

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      https://www.ias.ac.in/article/fulltext/pram/006/05/0278-0283

    • Keywords

       

      Nematic liquid crystals; dielectric anisotropy; cyanobiphenyl

    • Abstract

       

      The principal dielectric constants of the pentyl to octyl derivatives of 4′-n-alkyl-4-cyanobiphenyl have been measured as functions of temperature in their nematic and isotropic phases. All the compounds exhibit a strong positive dielectric anisotropy due to the presence of a large dipole moment along the major molecular axis. The principal dielectric constantsε andε as well as the anisotropy Δε decrease with increasing alkyl chain length. The experimental value of$$\bar \in = \frac{1}{3}$$ (ε+2ε) decreases with decreasing temperature, and is throughout less than the extrapolated isotropic value, in conformity with the model of antiferroelectric short range order proposed by Madhusudana and Chandrasekhar.

    • Author Affiliations

       

      B R Ratna1 R Shashidhar1

      1. Raman Research Institute, Bangalore - 560006
    • Dates

       
  • Pramana – Journal of Physics | News

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      Posted on July 25, 2019

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