Research

Colloidal liquid crystals

A colloidal liquid crystal is a suspension of anisotropic particles able to self-assemble into ordered phases. Example of colloidal liquid crystals are biological (some DNA origami, viruses, actin bundles, collagen systems, nanocellulose, etc.) but also industrial. For example the company Teijin Aramid produces polyaramids fibers reinforced by liquid crystalline order, a method shared by spiders producing their silk.

The innovative training network DiStruc aimed to understand and direct structure formation in dispersions of elongated colloidal particles by internal (particle characteristics, interactions and concentration) and external means (confinement and flow). Louis' part of the project focused on repulsive particles in a gravitational field and confinement. Louis studied both the phase behavior and the dynamics of the rods as a function of concentration.

Molecular dynamic simulation snapshot of hard rods at sedimentation-diffusion equilibrium.

dz_10_zoom.avi

Self-diffusion of tracer silica in the smectic phase, tracer particles are image by confocal microscopy and tracked overtime to measure dynamical properties.

Packing of silica rods in annular confinement (experiments). The particles are imaged by bright field microscopy, detected and colored (as a function of their orientation relative to the closest wall).