THE EFFECTS OF GRAVITY ON THE AGGREGATION AND THE GELATION OF COLLOIDS

This paper deals with the effects of gravity on the aggregation and th e gelation of colloidal suspensions. After reviewing some basic result s in the field of colloidal aggregation phenomena in section 2, we tur n our attention in section 3 towards the coupling which takes place be tween clustering and sedimentation once the aggregates have reached so me critical size. In section 4, we investigate the effects of gravity on the space-filling connected networks which exist in gelled suspensi ons. We report on a general method for investigating the equilibrium o f tenuous connected structures under gravity and we discuss two differ ent asymptotic behaviours which correspond respectively to gelling col loidal suspensions and polymer gels in relation with experimental inve stigations.