Short-range dynamics of a nematic liquid-crystalline phase

TL;DR

This study investigates the scale-dependent collective dynamics of a nematic liquid-crystalline phase of nanorods using x-ray photon correlation spectroscopy, revealing significant slowing down at larger length scales compared to isotropic suspensions.

Contribution

It provides the first detailed analysis of how the hydrodynamic function varies with wave vector in a nematic phase of nanorods, highlighting strong scale-dependent dynamical slowing down.

Findings

Hydrodynamic function decreases by over a factor of 10 at larger scales.

Collective dynamics slow down significantly compared to isotropic suspensions.

The diffusion coefficient varies sharply with wave vector in the nematic phase.

Abstract

Using x-ray photon correlation spectroscopy, we studied the dynamics in the nematic phase of a nanorodsuspension. The collective diffusion coefficient in the plane perpendicular to the director varies sharply with the wave vector. Combining the structure factor and the diffusion coefficient, we find that the hydrodynamic function of the phase decreases by more than a factor of 10 when going from length scales comparable to the interparticle distance toward larger values. Thus, the collective dynamics of the nematic phase experiences strong and scale-dependent slowing down, in contrast with isotropic suspensions of slender rods or of spherical particles.