Molecular alignment of the 4‐octyl‐4′‐cyanobiphenyl liquid crystal filled with SiO₂

Abstract

The molecular dynamics and molecular alignment of the dispersed 4‐octyl‐4′‐cyanobiphenyl (8CB) liquid crystal with 5 wt % of SiO₂ nanosphere particles have been studied using dielectric spectroscopy. The measurements were performed in the frequency range between 10²–10⁷ Hz in the SmA, N and I phases. The results show only one Debye relaxation process at high frequency (10⁵–10⁷ Hz). In the bulk material, activation energies of 40, 58 and 63 kJ mol⁻¹ were determined for the SmA, N and the I phases, respectively. In the dispersed sample, the activation energies were found to be 52, 76 and 81 kJ mol⁻¹, respectively. These results are compared with the available data in the literature. The reversible electromechanical response of the dispersed sample under the influence of an applied a.c. electric field was investigated in the SmA, N, and I phases.

Acknowledgement

The research presented in this report is supported by a bilateral agreement between Ulm and Cairo universities.