Abstract: The stability of Agl sols in SDS, PVPand their mixed solutions has been studied. The addition of SDSincreases the stability of Agl sols mainly by the increase of zeta potential of Agl particles due to the adsorption of surface active anions on particle surface. The Agl sols are sensitized at low PVPconcentration, and become stable through the steric stabilization of the adsorbed layer at high PVPconcentration. In the mixed solutions of PVPand SDS, the stability of Agl sols is enhanced markedly. This synergistic effect of PVPand SDSon the stability of Agl sols was discussed in terms of the interaction between polymer and surfactant at solid/liquid interface.

Key words: Stability of AgI sols, Sodium dodecylsuJfate, Polyvinylpyrrolidone