ABSTRACT
We investigate the behavior of colloidal suspensions with different volume fractions confined between parallel walls under a range of steady shears. We model the particles using molecular dynamics (MD) with full hydrodynamic interactions implemented through the use of a lattice-Boltzmann (LB) fluid. A quasi-2d ordering occurs in systems characterized by a coexistence of coupled layers with different densities, order, and granular temperature. We present a phase diagram in terms of shear and volume fraction for each layer, and demonstrate that particle exchange between layers is required for entering the disordered phase.
ABSTRACT
We use a Landau de Gennes free energy approach to model a diamond colloidal crystal immersed in a cholesteric liquid crystal. The pitch in our cholesteric is chosen in order to give rise to the most energetically favourable colloid-defect structure, commensurate with the diamond lattice. This structure corresponds to defect lines travelling along symmetry axes in the diamond crystal. By adding noise to the liquid crystal phase we are able to measure the phonon spectrum of our colloidal crystal, which we find to be consistent with a locally stable configuration. Therefore, although it may not correspond to the global minimum energy structure, once formed our diamond lattice should be stable against thermal fluctuations.
