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Adsorption kinetics of alkanethiol-capped gold nanoparticles at the hexane–water interface

Ferdous, Sultana and Ioannidis, Marios A. and Henneke, Dale (2011) Adsorption kinetics of alkanethiol-capped gold nanoparticles at the hexane–water interface. Journal of Nanoparticle Research, 13 (12). pp. 6579-6589.

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Abstract

The pendant drop technique was used to characterize the adsorption behavior of n -dodecane-1-thiol and n -hexane-1-thiol-capped gold nanoparticles at the hexane–water interface. The adsorption process was studied by analyzing the dynamic interfacial tension versus nanoparticle concentration, both at early times and at later stages (i.e., immediately after the interface between the fluids is made and once equilibrium has been established). A series of gold colloids were made using nanoparticles ranging in size from 1.60 to 2.85 nm dissolved in hexane for the interfacial tension analysis. Following free diffusion of nanoparticles from the bulk hexane phase, adsorption leads to ordering and rearrangement of the nanoparticles at the interface and formation of a dense monolayer. With increasing interfacial coverage, the diffusion-controlled adsorption for the nanoparticles at the interface was found to change to an interaction-controlled assembly and the presence of an adsorption barrier was experimentally verified. At the same bulk concentration, different sizes of n -dodecane-1-thiol nanoparticles showed different absorption behavior at the interface, in agreement with the findings of Kutuzov et al. (Phys Chem Chem Phys 9:6351–6358, 2007 ). The experiments additionally demonstrated the important role played by the capping agent. At the same concentration, gold nanoparticles stabilized by n -hexane-1-thiol exhibited greater surface activity than gold nanoparticles of the same size stabilized by n -dodecane-1-thiol. These findings contribute to the design of useful supra-colloidal structures by the self-assembly of alkane-thiol-capped gold nanoparticles at liquid–liquid interfaces.

Item Type:Article
ID Code:11468
Deposited By:Prof. Alexey Ivanov
Deposited On:05 Jan 2012 09:29
Last Modified:05 Jan 2012 09:42

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