Title: Plasticised polymer inclusion membrane as tunable host for stable gold nanoparticles

Authors: Rakesh Kumar, Ashok K. Pandey, A. Goswami, R. Shukla, Shobha V. Ramagiri, Jayesh R. Bellare

Addresses: Research Reactor Services Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. ' Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. ' Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. ' Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India. ' Department of Chemical Engineering, IIT Bombay, Powai, Mumbai 400 076, India. ' Department of Chemical Engineering, IIT Bombay, Powai, Mumbai 400 076, India

Abstract: Stable Au nanoparticles (nps) were synthesised in matrix of the self-supported plasticised polymer inclusion anion-exchange membrane using the ion-exchange route for loading AuCl4 anions in membrane and their subsequent reduction with BH4 anions. The compositions of membrane was varied by changing concentration of the anion exchanger, and also using different plasticiser. X-ray diffraction patterns of the membrane samples embedded with Au nps were taken to study the parameters involved in the formation of Au nps in the plasticised polymer matrix. The content of Au nps in the membrane was increased by: 1) repeating the sequential cycles of loading of AuCl4 ions followed by the reduction with BH4 in the membrane matrix; 2) increasing the concentration of anion exchanger in the membrane matrix. It was observed in TEM images of cross section of membrane that spherical Au nps of 10 nm sizes were dispersed throughout the matrix of membrane. The increase in Au0 content in the membrane did not alter the average size of Au nps significantly, but slightly increased the range of size distribution. The nanostructures like prism, rod, sphere, bipyramid and cuboid were also observed in the membrane matrix, but their number density was 5% of nanoparticles present in the membrane matrix. The analyses of isotopic-exchange rate profiles of iodide ions between the membrane sample and well-stirred equilibrating salt solution indicated that formation of Au nps lead to a significant increase in self-diffusion mobility of the anions in membrane. The surface plasmon band (SPB λmax = 535 nm) of Au nps did not change on equilibration of the membrane samples with the solutions containing Cl, I, ClO4, and CH3COO anions, but completely disappeared on equilibration with solution containing molecular iodine.

Keywords: polymer inclusion membranes; gold nanoparticles; ion exchange; plasticisers; diffusion properties; nanotechnology.

DOI: 10.1504/IJNT.2010.034701

International Journal of Nanotechnology, 2010 Vol.7 No.9/10/11/12, pp.953 - 966

Published online: 17 Aug 2010 *

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