Multi-scale modelling of particles and interfaces in complex fluids

点击翻译按钮获取中文摘要

My research focus is on modelling particles and interface phenomena in complex fluids, particularly colloids in liquid crystals and interface-driven fluid dynamics at the micro- and nano-scale. The objectives are three-fold: (1) To provide a tool for studying in-vivo microrheology of anisotropic fluid environments, such as those naturally occurring in biological systems. (2) To improve our understanding of colloidal nematic suspensions so that self-assembled structures, such as those suggested as the basis of 3D photonic band-gap materials, can be manipulated and constructed in a controlled fashion.  (3) To construct models for surface-dominated flow regimes relevant for micro- and nano-fluidic devices.To achieve these goals I will use continuum models whose functional form and constitutive coefficients will be based on the results of molecular dynamics (MD) simulations.  Specifically, MD simulations will be used to characterize the interactions between objects immersed in a liquid crystal, such as nanowires, that arise from a competition between the bulk orientational order of the liquid crystal and the preferred ordering at the surface of the colloidal inclusion.  The molecular origin of the surface elasticity and orientational ordering for both solid and liquid inclusions will be explored. The results of the MD simulations will guide the design of lattice Boltzmann models.  These models will be employed to study  (1) the viscoelastic response of nanowires immersed in an anisotropic fluid and (2) colloidal suspensions of spheres in liquid crystals that form self-organized lattice structures.  Goal (3) will involve a similar mapping of molecular dynamics to continuum models for polar fluids.  It will be necessary to go beyond a standard continuum description of the fluid and to include electrostatic effects related to surface charge densities.   The resulting model will be used to explore the problem of droplet motion in microfluidic devices driven by electrowetting and other surface stress gradients at the solid-fluid wall.