Abstract
An environmentally friendly route to prepare stable concentrated aqueous dispersions of silver nanoparticles is described. It was found that Arabic gum, a well known stabilizing agent, can also rapidly and completely reduce Ag2O to metallic silver in alkaline solutions (pH > 12.0) and elevated temperature (65 degrees C). The average size of the silver nanoparticles could be tailored from 10 to 30 nm by varying the experimental conditions. By hydrolyzing either enzymatically or chemically the polysaccharide, it was possible to isolate dispersed silver nanoparticles suitable for both biological and printable electronics applications. For the latter purpose, concentrated dispersions of silver particles were prepared and used for depositing thin uniform layers, which could be sintered into conductive films at low temperatures.