SRD-MD modelling of hydrodynamic interactions in colloidal systems: playing between computational cost and resolution

摘要

A ubiquitous problem that has always been a subject of intensive research is the role played by hydrodynamic interactions (HIs) in several fundamental problems in colloid rheology and aggregation kinetics. However, the high computational demand that is often associated with HIs modelling presents a huge challenge. Even with the computer power that is available today, a full molecular dynamics simulation is still unsustainable. Meanwhile, there is a diverse number of technological applications that call for a means to address this limitation. To that end, we use a hybrid Stochastic Rotation Dynamics - Molecular Dynamics (SRD-MD) method, which can provide a compromise between computational efficiency and molecular dynamics resolution. We present our SRD-MD simulation results in two parts. The first one is modelling of the Theological behaviour of colloidal suspensions. We successfully reproduce, both qualitatively and quantitatively, the divergence of the suspension viscosity from linear behaviour when HIs are properly included. The second part deals with the aggregation kinetics of colloidal suspensions. We show that HIs speed up the aggregation process of colloids and slow down the reorganization of the clusters formed. Consequently, we demonstrate that the probability of percolation is higher for systems with HIs in comparison with systems without.