Dielectric Hysteresis, Relaxation Dynamics, and Non-volatile Memory Effect in Carbon Nanotube Dispersed Liquid Crystal

TL;DR

This study explores the dielectric hysteresis, relaxation dynamics, and non-volatile memory effects in a nematic liquid crystal system dispersed with carbon nanotubes, revealing ferroelectric-like behavior and potential for nanoelectromechanical applications.

Contribution

It demonstrates the intrinsic dielectric and relaxation properties of LC+CNT composites, highlighting their non-volatile memory effects and ferroelectric-like behavior in the nematic phase.

Findings

Dielectric hysteresis observed in LC+CNT system.

Non-volatile memory effect due to pseudo-nematic domains.

Temperature-dependent dielectric constant indicating ferroelectric-like behavior.

Abstract

The self-organizing properties of nematic liquid crystals (LC) can be used to template carbon nanotubes (CNTs) on a macroscopic dimension. The nematic director field, coupled to the dispersed CNT long-axis, enables controlled director reorientation using well-established methods of LC alignment techniques, such as patterned-electrode-surface, electric fields, and magnetic fields. Electric field induced director rotation of a nematic LC+CNT system is of potential interests due to its possible applications as a nano electromechanical system. The relaxation mechanism for a LC+CNT composite, on the removal of the applied field, reveals the intrinsic dynamics of this anisotropic system. Dielectric hysteresis and temperature dependence of the dielectric constant coherently shows the ferroelectric-type behavior of the LC+CNT system in the nematic phase. The strong surface anchoring of LC molecules on CNT walls results in forming local isolated pseudo-nematic domains in the isotropic phase. These domains, being anisotropic, respond to external fields, but, do not relax back to the original state on switching of the field off, showing non-volatile memory effect.