The negative environmental and economic impacts of organic solvents in gold nanoparticle (AuNP) synthesis motivate the search for more environmentally benign alternatives. One viable alternative is the synthesis of AuNPs from tetrachloroauric (III) acid (HAuCl4) using triblock copolymers (TBPs) as reducing and stabilizing agents. However, the nanocrystals produced are heterogeneous in shape and size. Establishing control over AuNP crystal formation requires a detailed mechanistic understanding of precursor reduction and nanoparticle growth. Using mixtures of TBPs (L31 and F68), a more flexible method to modulate size and shape is demonstrated. These goals can be achieved by adjusting concentrations of seed citrate-stabilized AuNPs and the TBP/Au (III) ratios. Kinetic models are used to explain why L31 inhibits the rate of AuNP formation and growth. Experimental evidence of sigmoidal growth kinetics, early time bimodal gold nanoparticle size distributions, and polycrystallinity suggest that aggregative AuNP growth is an important contributing mechanism.

Kinetically controlled seeded growth synthesis of triblock-copolymer stabilized gold nanoparticles: Size focusing vs. Ostwald ripening

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.