THEORY OF SLOW DYNAMICS IN HIGHLY-CHARGED COLLOIDAL SUSPENSIONS

A systematic theory for the dynamics of charge-stabilized colloidal su spensions of interacting Brownian. particles with both Coulomb and hyd rodynamic interactions is presented. A nonlinear deterministic diffusi on equation for the average local volume fraction of macroions Phi(x,t ) and a linear stochastic diffusion equation for the nonequilibrium de nsity fluctuations around Phi, both of which contain an anomalous self -diffusion coefficient D(s)similar to[l - Phi(x,t)/phi(g)](gamma), der ived, where gamma=1 here. The glass transition volume fraction phi(g) is found to be small as phi(g)similar to(Zql(B)/a)(-3) for highly char ged colloidal suspensions with Z much greater than q, where Ze is the charge of the macroions, -qe is the charge of counterions, Is is the B jerrum length, and a is the radius of the macroions. The dynamic anoma ly of Ds(QI), which results from the correlations among macroions and counterions, due to long-range Coulomb interactions, is shown to cause slow dynamical behavior near phi(g). This situation is exactly the sa me as that of the hard sphere suspensions previously discussed by the present author, where gamma=2.