ABSTRACT

Polysilicates or sols of very small particles are stabilized

by having sufficient alkali in the system. Yates (41) pro-

posed that alkali-stabilized sols are stable not only

against gelling, but also in the thermodynamic sense. He

pointed out that there are thermodynamic factors that

prevent the spontaneous growth of particles or their aggre-

gation and stabilize the high interfacial solid-liquid inter-

face in the silica-water system. The main factor that

counterbalances the free energy change involved in loss

of surface area in the silica-water system is the strong

adsorption of the continuous liquid phase or of stabilizing

counterions or of other adsorbed species at the surface of

the dispersed phase, thus changing the free energy of the

interface.