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Dielectric investigations on a bent-core liquid crystal

Abstract:

Dielectric measurements on a bent-core liquid crystal were carried out in the frequency range from 10 mHz to 100kHz in planar aligned cells. Four relaxation ranges were detected during heating condition: two in a low frequency range of a few hertz probably due to conductivity and interface relaxation phenomena, another between 10 and 20Hz, and another one in a range between 10kHz and 100kHz in smectic as in nematic and isotropic phases. The third relaxation response is no more visible during cooling conditions. Dielectric increments, distribution parameters, and relaxation frequencies have been evaluated at different temperatures by fitting data with Havriliak-Negami (H-N) relaxation function, which is an empirical modification of the Debye relaxation model. The presence of a relaxation response between 10 and 20Hz and the relatively great values of the permittivity could suggest the presence of a ferroelectric response due to the presence of cybotactic clusters. © 2012 American Institute of Physics.