2020 Volume 56 Issue 5 Pages 182-189
In colloidal suspensions, electrostatic interactions, hydrodynamic interactions, and their dynamic coupling are of crucial importance both in statics and kinetics of structure formation and rheology, leading to the emergence of various functions of charged soft matter in technological applications and biological cells. From the theoretical and computational viewpoints, however, it has been very challenging to take electrostatic and hydrodynamic interactions into account because both are long-ranged many-body interactions. Another difficulty originates from the fact that the number of charges on colloidal surfaces is determined by chemical equilibrium, and thus, affected by the presence of other colloids or charged surface. Fluid Particle Dynamics （FPD） method is a powerful method to deal with these problems in a physically transparent manner. We here review the concept of the FPD method incorporating the self-organization of colloidal charges - charge regulation. We describe the details of the theoretical formulation to treat long-range electrostatic and hydrodynamic interaction. We also show two computational results where charge regulation becomes relevant as examples. Our method is applicable to more complex problems of charged soft matter systems.
