Diffusivity in an electric-field–induced homeotropic phase of charged colloidal rods

Forschungszentrum Jülich, IFF-7, Soft Condensed Matter - D-52425 Jülich, Germany, EU

^a k.kang@fz-juelich.de

Received: 20 August 2010
Accepted: 20 September 2010

Abstract

This paper discusses the diffusivity of charged colloidal rods (fd-viruses) at high concentrations in a uniform homeotropic phase that is induced by an external electric field. With dynamic light scattering two dynamical modes are found, which are contributed to diffusion parallel and perpendicular to the nematic director. At high fd concentration and low ionic strength, where inter-rod interactions are particularly strong, unexpected dispersion relations are found for the fast-mode relaxation rate. This is partly attributed to a possible chiral nature of the homeotropic phase. At very low ionic strength, thermal motion is hindered to an extent that a solid-like dispersion relation is found.