Phase transfer of Au–Ag alloy nanoparticles from aqueous medium to an organic solvent: effect of aging of surfactant on the formation of Ag-rich alloy compositions

Devarajan, Supriya and Vimalan, B and Sampath, S (2004) Phase transfer of Au–Ag alloy nanoparticles from aqueous medium to an organic solvent: effect of aging of surfactant on the formation of Ag-rich alloy compositions. In: Journal of Colloid and Interface Science, 278 (1). pp. 126-132.

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Abstract

Mercaptopropionic acid (MPA) capped Au–Ag alloy nanoparticles consisting of various mole fractions of gold and silver have been synthesized in aqueous medium using a citrate reduction method. UV–visible spectra confirm the formation of alloy phases and transmission electron microscopy (TEM) reveals a rather uniform distribution of several nanometer-sized particles. The particles could easily be phasetransferred into organic solvents, isolated, and redispersed in a variety of solvents such as benzene, chloroform, and dichloromethane. The phase transfer from aqueous medium to an organic solvent does not alter the particle size and distribution. It is also recognized that the surfactant, alkaline MPA, should be aged for about 3 days in order to observe the formation of silver and silver-rich phases of alloy nanoparticles. The reason for this observation is discussed in terms of the competitive interaction between the Na+ and –COOH/–SH groups and subsequent reduction of metal ions.

Item Type:	Journal Article
Publication:	Journal of Colloid and Interface Science
Publisher:	Elsevier
Additional Information:	The copyright belongs to Elsevier
Keywords:	Nanoparticle;Au–Ag alloy;Citrate;Phase transfer;Sodium mercaptopropionate
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	19 Apr 2006
Last Modified:	19 Sep 2010 04:25
URI:	http://eprints.iisc.ac.in/id/eprint/6346

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