Diffusion in complex fluids

Dispersions of colloidal viruses, in our case fd virus, display a cascade of phase transitions, from isotropic to the nematic [Lettinga2005], the smectic [Lettinga2007, Pouget2011] and the columnar [Naderi2013] phase with increasing concentration. Uncovering the dynamics underlying these phase transitions, which is fundamental to understand the process of self-assembly, as it is purely driven by entropy. We use fluorescence video microscopy in order to study the self-diffusion of rods in the different phases. This study gave and still gives a wealth of surprising features, such as discretised Brownian diffusion in the smectic and large rods that diffuse faster than short rods.