Preparation of acrylate-stabilized gold and silver hydrosols and gold-polymer composite films

Gold and silver nanoparticles were prepared by reducing aqueous solutions of the respective metal salts with sodium acrylate (SA), which also acts as capping agent. Gold nanoparticles were also prepared using poly(sodium, acrylate) (PSA) with various molecular weights (2100, 5100, 15 000, and 30 000 g/mol). These polymers act as both reducing and stabilizing agents for the gold nanoparticles. Gold nanoparticles formed using SA are nearly spherical and have a narrow size distribution (11-17 nm). These particles are similar in size and stability to those formed by the conventional citrate reduction method. PSA-stabilized gold nanoparticles are somewhat less uniform in size but also highly stable. The polymer-stabilized gold particles can be used to form composite polymer films with optical properties that depend on the volume fraction of gold.