Aqueous synthesis and stabilization of highly concentrated gold nanoparticles using sterically hindered functional polymer

This letter describes a simple and bulk route for synthesizing Au nanoparticles in a sub-10 nm regime using branched polyethyleneimine (BPEI) as a stabilizer. BPEI, a sterically hindered functional polymer, was found to play a key role in stabilizing the Au nanoparticles without any aggregation, even at a high chloroauric acid concentration of 200 mM.