Fluid particle dynamics simulation of charged colloidal suspensions

A new method of simulation of the dynamics of charged colloidal suspensions is formulated that is based on the fluid particle dynamics method (Tanaka and Araki 2000 Phys. Rev. Lett. 85 1338) so as to incorporate the electrohydrodynamic interactions properly. The fluid particle approximation allows us to treat dynamic coupling among motions of the three relevant elements of charged colloidal suspensions, i.e., colloidal particles, ion clouds, and liquid, in a physically natural manner. The validity of our method is demonstrated for a problem of the electrophoretic deposition of charged colloids. Our simulation results clearly indicate that the electro-osmotic flow causes 'effective' long-range attractions between charged particles of the same sign, as previously suggested by experiments and theories. (letter to the editor)