Microstructure and viscosity of aggregating colloids under strong shearingforce

Disaggregation under strong shearing force is simulated for an aggregating colloid based on a sticky particle model which can describe the disaggregat ing and aggregating kinetics, the deformation, and the rupture of clusters with a minimum number of parameters. For a 2-dimensional system, the viscos ity and coordination number of the model colloid are calculated at each tim e step, and the changes of microstructure with shear flow are observed dire ctly by displaying the configuration of particles onto a monitor. The visco sity depends on both area fraction and shear rate, but coordination number depends only on shear rate. Furthermore, the viscosity and coordination num ber at steady state are independent of the initial state of particles, whic h indicates that the disaggregation and aggregation are mutually reversible . (C) 1999 Academic Press.