Preparation of stable sols of silver nanoparticles in aqueous pectin solutions and properties of the sols

Silver nanoparticles have been synthesized by reducing AgNO3 in an alkaline medium under the action of a natural polysaccharide, pectin. The influences of the type of pectin used and the reagent mixing order during the synthesis on the sizes and plasmon resonance properties of nanoparticles have been studied by optical spectroscopy and transmission electron microscopy. The conditions that make it possible to obtain silver hydrosols having predetermined particle sizes of 8 +/- 2 to 22 +/- 6 nm and stable to aggregation for at least 3 months have been determined.