ADHESION BETWEEN COLLOIDAL SILICA AS SEEN WITH DIRECT FORCE MEASUREMENT

Direct force measurements are reconciled with the well-known anomalous colloidal behavior of silica sols, To overcome the difficulty of surf ace-altering treatments the force between layers of nanometric colloid al silica particles adsorbed from solution is measured using a surface force apparatus, Coating substrates with nanometric particles gives a surface that is smooth only at the nanometer scale, but which is full y representative of a colloidal silica-water interface. Force measurem ents and colloidal stability can thus be compared, leading to direct e vidence of chemical adhesion between silica particles. (C) 1997 Academ ic Press.