Molecular-Level Relation between the Intraparticle Glass Transition Temperature and the Stability of Colloidal Suspensions

In many colloidal suspensions, the dispersed colloidal particles are amorphous solids, resulting from vitrification. A crucial open problem is understanding how colloidal stability is affected by the intraparticle glass transition. By dealing with the latter process from a solid-state perspective, we estabilish a proportionality relation between the intraparticle glass transition temperature, T-g, and the Hamaker constant, A(H), of a generic suspension of nanoparticles. It follows that T-g can be used as a convenient parameter (alternative to A(H)) for controlling the stability of colloidal systems. Within the Derjaguin-Landau-Verwey-Overbeek theory, we show that the novel relationship, connecting T-g to A(H), implies the critical coagulation ionic strength to be a monotonically decreasing function of T-g. We connect our predictions to recent experimental findings.