The Influence of Surfactants and Polymers on the Kinetics of Modified Tollens Reaction at Preparation of Silver Nanoparticles

The presented contribution is aimed on the study of influence of various surfactants and polymers on the kinetics of reduction of diamminsilver complex cation in alkaline media using D-maltose as a reducing sugar (modified Tollens reaction). From the group of surfactants, the following types were used: anionic (sodium dodecylsulfate and sodium dodecylbenzenesulfonate), cationic (cetyltrimethylammonium chloride and cetylpyridinium chloride), and nonionic surfactants (Tween 80 and Triton X-100). From the group of polymers some typical natural (gelatine, casein, cellulose) and synthetic (polyacrylic acid, polyvinylpyrrolidone, polyethylene glycol) polymers were studied. These polymers are applied in practice as stabilizers of colloidal dispersions. It was generally observed that polymers influenced kinetics of the studied reaction more intensive than the surfactants. Both of the natural polymers with N-heteroatoms in their molecule (gelatine and casein) substantially decreased the reaction rate. In contrast to this effect the anionic surfactant SDS sharply increased reaction rate of the studied reaction. From the point view of the influence of the studied substances on the size of the prepared silver nanoparticles, the polymers caused increase in the nanoparticle diameter while in the presence of surfactants the size of the prepared silver nanoparticles was smaller. The mechanism, how could the tested substances influence the kinetics of studied reaction, is discussed.