A novel method for measuring electric field induced dipole moments of metal-dielectric Janus particles in nematic liquid crystals

TL;DR

This paper introduces a new method to measure the electric field-induced dipole moments of metal-dielectric Janus particles in nematic liquid crystals by analyzing the balance of elastic and electrostatic forces, with results aligning well with theoretical models.

Contribution

The study presents a novel experimental approach for quantifying induced dipole moments of Janus particles in anisotropic media, advancing understanding of their electro-mechanical behavior.

Findings

Effective dipole moments measured match theoretical predictions.

The method provides a reliable way to characterize Janus particles in liquid crystals.

Results facilitate the design of functional materials using Janus particles.

Abstract

Janus particles are special types of nano or micro particles possessing at least two surfaces with distinct physical or chemical properties. The most studied Janus particles are the metal-dielectric particles, in which half surface of dielectric particles is coated with a very thin layer of metals. The external electric field induces dipole moment, and consequently the particles exhibit self-assembled dynamic structures in concentrated aqueous suspensions. Here, we study metal-dielectric Janus particles in a nematic liquid crystal under AC electric field and demonstrate a novel method for measuring effective induced dipole moments of the particles, through competition between elastic and electrostatic (Coulomb) forces of the two particles. The calculated polarisability of the particles based on a simple model agrees well with the effective polarisability measured in the experiments. Our findings have important bearing on functional materials based on metal-dielectric Janus particles dispersed in an anisotropic medium.