Self-diffusion in isotropic and liquid crystalline phases of fd virus colloidal rods: a combined single particle tracking and differential dynamic microscopy study

TL;DR

This study combines single particle tracking and differential dynamic microscopy to analyze the complex self-diffusion behavior of fd virus colloidal rods across various liquid crystalline phases, providing new insights into their dynamics.

Contribution

It introduces a combined methodological approach using SPT and DDM to study anisotropic colloidal rod dynamics across multiple self-assembled phases, revealing phase-dependent diffusion characteristics.

Findings

Long-time diffusion coefficients measured in the smectic phase.

Comparison of SPT and DDM highlights their complementary strengths.

Insights into the dynamics of viral colloidal rods in different phases.

Abstract

In this article, we investigate the dynamics of self-organised suspensions formed by rod-like fd virus colloids. Two methods have been employed for analysing fluorescence microscopy movies: single particle tracking (SPT) in direct space and differential dynamic microscopy (DDM) in reciprocal space. We perform a quantitative analysis on this anisotropic system with complex diffusion across different self-assembled states, ranging from dilute and semi-dilute liquids to nematic and smectic organisations. By leveraging the complementary strengths of SPT and DDM, we provide new insights in the dynamics of viral colloidal rods, such as long time diffusion coefficients in the smectic phase. We further discuss the advantages and limitations of both methods for studying the intricate dynamics of anisotropic colloidal systems.