Ag2S Interparticle Interaction in an Aqueous Solution: Mechanism of Steric and Electrostatic Stabilization

Abstract In this study, two types of stable Ag2S nanoparticle solutions with negative and positive zeta-potential and different stabilization mechanisms were synthesized by a chemical precipitation method. The first type was stabilized by adding 3-mercaptopropyl-trimethoxysilane (MPS) to provide steric stability of nanoparticles. It was found, that the MPS molecules could effectively stabilize the system covering about 20% of the nanoparticle’s surface. For the second type, a simple method suggested in this work was used for the first time. This novel method is based on the addition of Na2S in great excess, which induces electrostatic stability of the solution with nanoparticles. The correlation between stability and parameters of nanoparticles has been established.