Related Experiment Video
Updated: Aug 16, 2026

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Waves at the nematic-isotropic interface: thermotropic nematogen-non-nematogen mixtures
V Popa-Nita1, T J Sluckin, S Kralj
1Faculty of Physics, University of Bucharest, P.O. Box MG-11, Bucharest 76900, Romania.
Abstract:
We develop a theory for surface modes at the nematic-isotropic interface in thermotropic nematogen-non-nematogen mixtures. We employ the dynamical generalization of the Landau-de Gennes model for the orientational (nonconserved) order parameter, coupled with the Cahn-Hilliard equation for concentration (conserved parameter), and include hydrodynamic degrees of freedom. The theory uses a generalized form of the Landau-de Gennes free-energy density to include the coupling between the concentration of the non-nematogen fluid and the orientational order parameter. Two representative phase diagrams are shown. The method of matched asymptotic expansions is used to obtain a generalized dispersion relation. Further analysis is made in particular cases. Orientational order parameter relaxation dominates in the short-wavelength limit, while in the long-wavelength limit viscous damping processes become important. There is an intermediate region (depending on the temperature) in which the interaction between conserved parameter dynamics and hydrodynamics is important.
Related Concept Videos
Intermolecular Forces and Physical Properties
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
Solid–Solid Solutions
Nonideal Two-Component Liquid Solutions
The Thermodynamics of Mixing

