goal requires an understanding of how physicochemical A theoretical framework has been developed for predicting and parameters for dispersions affect interparticle interacexplaining the colloidal stability of concentrated dispersions. It is tions. Such insight, though well developed for dilute colbased on multiparticle interaction models for the electrical double loids, is yet to be unveiled fully for concentrated systems. layer (EDL) and van der Waals (vdW) interactions. An asymmet-Our motivation derives from this void, and from the deric cell model is used for estimating EDL interaction energy from sire of addressing formulation challenges with these systhe solution of the Poisson-Boltzmann equation. The unretarded tems conceptually, rather than empirically.
vdW interaction energy is calculated via Hamaker's method,
Classical analysis of flocculation in dilute dispersions
adopting the pairwise-additivity approach. Various dispersion parameters are investigated for their effects on the flocculation en-delineates the basic phenomena controlling this process. ergy barrier. These include volume fraction, size, and surface po-These concepts, fundamental to our treatment, are outtential of particles, as well as the ionic strength of the dispersing lined below, starting with interaction forces. Electrical medium. The results show several new trends borne out of multidouble layer ( EDL ) repulsion and van der Waals ( vdW ) particle interaction effects. A maximum in the energy barrier is attraction are two major interactions governing most colpredicted as a function of salinity, contrasting the monotonic deloidal phenomena. A layer of fixed charge on a surface, pendence from the classical DLVO theory. This salinity depenand a part of the surrounding electrolyte where a diffuse dence of the energy barrier provides the first comprehensive explalayer of excess counterions counterbalances the surface nation of reported experimental findings on stability and rheologicharge, constitute an EDL. The EDL interaction between cal properties of concentrated dispersions. Other predictions charged colloids originates from the overlapping of their include the occurrence of flocculation at a secondary minimum and the particle-size dependent variation of suspension stability electrical double layers. On the other hand, their vdW with particle volume fraction.