Investigation of antisolvent effect on gold nanoparticles during postsynthesis purification

Gold nanoparticles (Au NPs) were synthesized by reducing HAuCl4 using borane tert-butylamine complex in the presence of alkylamine (dodecylamine, hexadecylamine, and octadecylamine) and didodecyldimethylammonium bromide. Ethanol was used as an antisolvent for the postsynthesis purification of Au NPs. Au NPs had uniform size distribution after first wash with ethanol and the aggregation and growth of Au NPs happened after second wash with ethanol. The Au NPs were characterized by TEM, SEM, XRD, H-1 NMR, UV-vis absorption and FTIR spectroscopy. The aggregated mechanism after the second wash with ethanol was proposed. Au NPs still retained their monodispersity after second wash compared with after first wash using the antisolvents, such as acetonitrile, dimethyl sulfoxide and acetone. The presented results suggest that the good choice of antisolvent is critical for the postsynthesis purification of Au NPs. (C) 2018 Elsevier Inc. All rights reserved.