Theoretical study on the effect of electric field for carbon nanotubes dispersed in nematic liquid crystal

Abstract

Nematic liquid crystal (NLC) plays an important role in the controlled alignment of carbon nanotubes (CNTs). When nematogens are strongly anchored over the surfaces of CNTs, the Liquid Crystal (LC) order parameter is greatly influenced. Moreover, the electro-optic properties of the medium are significantly improved. Application of electric field further modifies these novel properties. The effect of electric field not only changes the phase behavior but also influences the ordering of both LC molecules and CNTs. Utilizing Doi and Landau–de Gennes type free energy mechanism, we have investigated in detail the changes incurred by the electric field. Order parameters of both LC and CNTs are calculated and modified phase diagrams are drawn. Finally, we have employed Landau–Khalatnikov equation to calculate rotational viscosity of the medium. It is found that rotational viscosity decreases with increasing volume fraction of CNTs in accordance with experimental results.