Research Center for Engineering of
                Systems with Complex Fluids
Title: The influence of particle clustering on the rheological properties of highly concentrated magnetic nanofluids
Published In: Journal of Colloid and Interface Science, Vol . 373, No. 1, pp. 110–115
Description: In this paper the particle volume fraction and temperature dependence of the dynamic viscosity of highlyconcentrated transformer oil based magneticnanofluids was investigated in the absence of an external magnetic field. The solid particle volume fraction dependence of the relative viscosity was found to be very well fitted by the Krieger–Dougherty formula, whence the mean ellipticity of the colloidal particles and the effective surfactant layer thickness were obtained. Using the information on the particles’ size and shape statistics obtained from TEM, DLS and magnetogranulometry investigations, it was concluded that the magnetite nanoparticles agglomerate in small clusters of about 1.3 particles/cluster, due to the van der Waals interactions. The effective thickness of the oleic acid surfactant layer was estimated as about 1.4 nm, in very good agreement with the value resulted from previous SANS investigations.
ISBN: 
ISSN:ISSN: 0021-9797
DOI:doi: 10.1016/j.jcis.2011.10.060
Publication year: 2012
Keywords:Magnetic fluid; Ferrofluid; Agglomeration; Dynamic viscosity; Magnetogranulometry; Dichroism; DLS; SLS; TEM
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Authors: SUSAN-RESIGA (GHEORGHE) Daniela , SOCOLIUC Vlad , BOROS Tibor , BORBATH Tunde , MARINICA (BALAU) Oana , HAN Adelina , VEKAS Ladislau ,
Type: International Journal Article
Link: http://dx.doi.org/10.1016/j.jcis.2011.10.060
Laboratory: Rheology Laboratory
Institution: ARFT