Aqueous phase synthesis of silver iodide nanoparticles from a polyacrylic acid–silver complex

Abstract

The conditions needed to form a complex of polyacrylic acid with silver ions (Ag+) in aqueous solution were investigated. Ag+ formed a complex with the dissociated carboxyl units of polyacrylic acid. It was found that the complex of polyacrylic acid with silver ions formed by disproportionation of Ag+ on polyacrylic acid macromolecules. When Ag+ and H+ coexisted in solution, the negatively charged carboxyl groups of polyacrylic acid preferentially interacted with H+. The size characteristics of the polyacrylic acid macromolecular coils and polyacrylic acid–silver complex and their volume ratio were investigated in solution. Silver iodide nanoparticles were synthesized under conditions where Ag+ formed a complex with polyacrylic acid, and when they were dispersed in bulk solution. The products were characterized by transmission electronic microscopy. The presence of the polyelectrolyte–silver complex as a precursor yielded silver iodide nanoparticles of smaller size and narrower size distribution, than those formed in the absence of the polyelectrolyte–silver complex.