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Indexed by:期刊论文

Date of Publication:2011-10-06

Journal:JOURNAL OF PHYSICAL CHEMISTRY C

Included Journals:Scopus、SCIE、EI

Volume:115

Issue:39

Page Number:18991-18998

ISSN No.:1932-7447

Abstract:Coarse-grained (CG) molecular dynamics (MD) simulations were carried out to investigate the dynamics of 2.2 nm monolayer-protected gold nanoparticles (AuNPs) in solvents. The effects of ligand length, ligand terminal chemistry, solvents, and temperature were examined. It was found that AuNPs with unmodified alkanethiol ligands formed stable aggregates in water in the time scale of hundreds of nanoseconds (eight nanoparticles). In a particular case, the AuNPs aggregated into an infinite, one-dimensional chainlike assembly instead of dusters of aggregates. The aggregates of AuNPs with short ligand tails seemed to have an amorphous shape, whereas long-tailed AuNPs aggregated into a spherical duster. The properties of ligand terminals had a dominant influence on the aggregation behavior of AuNPs. Increasing the polarity of the ligand terminals weakened the tendency of aggregation of AuNPs in water. For AuNPs imposed with charged terminals, they did not aggregate even with a high concentration of salt. However the aggregation behavior of AuNPs changed dramatically if the properties of solvent were altered. Temperature increase greatly accelerated the process of aggregation. The results suggest that the dynamics of monolayer-protected AuNPs can be controlled by their surface properties as well as the features of solvents.