Title: Micro-structural characterisation of water-based magnetic fluid

Authors: R.V. Upadhyay; V.K. Aswal; Rucha Desai

Addresses: P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT-Campus, Changa - 388421, India. ' Solid State Physics Division, Bhabha Atomic Research Center, Trombay, Mumbai - 400085, India. ' P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, CHARUSAT-Campus, Changa - 388421, India

Abstract: The present paper elucidates microstructure analysis of aqueous base dilution insensitive magnetic fluid using different experimental techniques. The structure of the particle was characterised using powder X-ray diffractometer, and it shows single phase spinel structure. The particle size (diameter) and lattice parameters obtained from the analysis are 8.4 ± 0.2 nm and 0.8338 nm, respectively. Average particle diameter and polydispersity index (PDI) obtained from dynamic light scattering experiment are 17 nm and 0.34, respectively. This gives a thickness of 4.3 nm around the particle. Transmission electron microscopy (TEM) image shows that particles are widely distributed with an average diameter 8.0 ± 1.3 nm. The in-field small angle neutron scattering analysis reveals a difference between the nuclear and magnetic radius of 0.7 nm, which results into a reduction of magnetisation by 40%. The observed higher value of field induced relative change in viscosity, Δη / η₀, indicates the formation of chain structure in the fluid. The maximum chain length is of five to six particles and is observed to be reversible.

Keywords: magnetic fluids; rheology properties; magnetic properties; small angle neutron scattering; SANS; microstructure.

DOI: 10.1504/IJNP.2012.048015

International Journal of Nanoparticles, 2012 Vol.5 No.3, pp.243 - 257

Received: 18 May 2011
Accepted: 02 Jul 2011
Published online: 20 Aug 2014 *

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