Critical-like behavior of ionic-related, low-frequency dielectric properties in compressed liquid crystalline 8OCB and its nanocolloid

TL;DR

This study investigates how pressure and nanoparticles influence the dielectric properties of liquid crystals, revealing critical-like behaviors and premelting effects near phase transitions through broadband dielectric spectroscopy.

Contribution

It introduces derivative-based analysis to describe ionic contributions and explores critical-like premelting effects in liquid crystal phase transitions.

Findings

Pressure and nanoparticles significantly affect dielectric properties.

Critical-like behavior observed near phase transitions.

Premelting effects detected in SmA to solid crystal transition.

Abstract

The report presents pressure-related broadband dielectric spectroscopy (BDS) studies in liquid crystalline octyloxycyanbiphenyl and its nanocolloid with BaTiO3 nanoparticles, focused on the low-frequency ionic domain and the impact of pretransitional fluctuations. Hence basic exogenic (pressure) and endogenic (nanoparticles) impacts on dielectric properties are addressed. The innovative derivative-based analysis revealed functional 'critical-like' descriptions of ionic contributions to dielectric permittivity and electric conductivity. The supplementary dielectric constant scan, yielding insight into dipole-diple arrangements, is also presented. Studies cover the puzzling case of complex liquid (SmA) - Solid crystal phase transition, revealing relatively strong critical-like premelting effects, which have hardly been observed for the discontinuous 'melting transition' so far.