Stokesian dynamics study of quasi-two-dimensional suspensions confined between two parallel walls

We present a Stokesian dynamics (SD) computer simulation study of the stati c and dynamical properties of a monolayer of spherical colloidal particles restricted to diffuse in the midplane between two parallel walls. SD simula tions account for hydrodynamic interactions (HI's) among the particles, and between particles and walls. Three different types of systems are studied: first, a monolayer of neutral spheres and neutral hard walls; second, part icles interacting by a repulsive Yukawa-type potential of range depending o n the wall separation. As a third system, the interesting case of charged p articles between charged parallel walls with a longer-range attractive part in the pair potential is investigated, using the experimentally determined effective pair potential of Acuna-Campa et nl. [Phys. Rev. Lett. 80, 5802 (1998)]. Various measurable quantities are calculated in dependence of the particle concentration and the wall distance: short- and long-time self-dif fusion coefficients, radial distribution functions and static structure fac tors, hydrodynamic functions, mean squared displacements, and van Hove real -space correlation functions. We assess the importance of HI's by comparing our results with simulation results where HI's are fully or partially disr egarded. Some of our results are also compared with experimental data, and good agreement is found. Remarkable effects are investigated, like the hydr odynamic enhancement of self-diffusion for the case of strongly charged par ticles, and the strong increase of the hydrodynamic function at small wave numbers. (C) 2000 The American Physical Society.