Deformable vesicles interacting in a nematic liquid crystals

deformed vesicle in a liquid crystalSpherically symmetric colloidal particles and suspensions have been extensively studied, both theoretically and experimentally.  While spherical colloids have many potential uses, particles with anisotropic interactions have a much higher potential as the synthetic building blocks for self-assembled materials with desirable properties, such as a photonic band-gap, at the nano- or micro-scale.  The anisotropic nature of liquid crystals (LCs) makes them an ideal candidate to generate non-spherically symmetric interactions between colloidal particles. The resulting liquid crystal defects and distortions lead to a non-uniform pressure exerted on the particle surface, accompanied by a deformation of its shape if it has a flexible surface. The interactions between pairs of vesicles can undergo discrete changes in shape coupled to defect movement as a function of their distance apart.

Hydrodynamic effects on confined polymers

Polymer confined between two platesRecent developments in promising micro and nanofluidic technologies have sparked a renewed interest in the statics and dynamics of confined polymers. We investigated the transition from 3D to 2D both for static and dynamic scaling of a single polymer as a function of its confinement between two rigid parallel plates. We consider two distinct types of confinement: (i) confinement for both the solvent and the polymer, and (ii) confinement for the polymer only (in a 3D solvent), which is experimentally feasible, for instance, by (optical) trapping. We demonstrate that, in the presence of hydrodynamics, the polymer's center-of-mass diffusion coefficient in the direction parallel to the walls scales differently as a function of the level of confinement in cases (i) and (ii). We also find that in the commonly used Langevin dynamics description, the polymer swells more parallel to the walls than in the presence of hydrodynamics, and the planar diffusion coefficient shows scaling behavior similar to case (ii) rather than case (i).

Welcome!

Our research focuses on modelling particles and dynamic processes in complex fluids.  We study systems involving micro- and nano-scale objects, soft colloids or polymers for instance, in a complex fluid such as a liquid crystal.  An important aspect of our work is the development of models and multi-scale computer simulation techniques to investigate these systems.

If you are interested in joining our group, please send me an email. We accept applications any time of the year. For more information about applying to the graduate program in Applied Math at Western, see our web page.