Patent ID: 7718094

Claim:
A method for producing metal nanoparticles, said method comprising the steps of: a) preparing a particle formation solution consisting essentially of a solvent, a first metal ion, a second metal ion, and a copolymer, said copolymer consisting essentially of a first polymer, which consists essentially of poly(ethylene oxide), poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(acrvlic acid), dextran, polysaccharide, gelatin, polyamine, or protein and a second polymer, which consists essentially of poly(propylene oxide), poly(butylene oxide), polydimethylsiloxane, polybutadiene, polystyrene, or polyethylene, wherein the first polymer is characterized as having a greater reducing activity than the second polymer and the second polymer is characterized as having a greater stabilizing activity than the first polymer; b) holding the solution from a) at a temperature such that a suspension of metal nanoparticles is formed in said particle formation solution; wherein nanoparticles comprising networks of the first metal inside the second metal are formed in step b); and wherein the first metal is silver and the second metal is gold; or wherein the first metal is gold and the second metal is silver.