Kinetically Controlled Synthesis of Triblock Copolymer Stabilized Gold Nanoparticles
Concerns for the environmental and economic impact of organic solvents in gold nanoparticle synthesis have motivated the search for more environmentally benign alternatives. One viable approach is the synthesis of AuNPs from tetrachloroauric(III) acid (HAuCl4) using triblock copolymers (TBPs). However, a major challenge of using TBPs is the heterogeneous nature of the formed nanocrystals. Establishing control over AuNP size and shape requires a detailed mechanistic understanding of precursor reduction and nanoparticle growth. By using mixtures of TBPs (L31 and F68), a more flexible method to tune AuNP size and shape is demonstrated. This is achieved by adjusting the TBP/Au(III) ratio and the concentrations of seed citrate-stabilized AuNPs. 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 mechanism.
Medical Biochemistry, Nanostructures; Chemical kinetics; Biochemistry; Solvents - Adverse Effects, Kinetics, Nanoparticles, Triblock Copolymer, Organic solvents - Environmental Impact
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