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Structure of water‐based ferrofluids with sodium oleate and polyethylene glycol stabilization by small‐angle neutron scattering: contrast‐variation experiments
Author(s) -
Avdeev Mikhail V.,
Feoktystov Artem V.,
Kopcansky Peter,
Lancz Gabor,
Garamus Vasil M.,
Willumeit Regine,
Timko Milan,
Koneracka Martina,
Zavisova Vlasta,
Tomasovicova Natália,
Jurikova Alena,
Csach Kornel,
Bulavin Leonid A.
Publication year - 2010
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889810025379
Subject(s) - ferrofluid , small angle neutron scattering , polyethylene glycol , dispersity , micelle , neutron scattering , chemical engineering , materials science , chemical physics , colloid , magnetite , nanoparticle , peg ratio , chemistry , scattering , polymer chemistry , nanotechnology , organic chemistry , optics , aqueous solution , magnetic field , physics , finance , quantum mechanics , economics , metallurgy , engineering
Contrast variation in small‐angle neutron scattering (SANS) experiments is used to compare the structures of a water‐based ferrofluid, where magnetite nanoparticles are stabilized by sodium oleate, and its mixture with biocompatible polyethylene glycol, PEG. The basic functions approach is applied, which takes into account the effects of polydispersity and magnetic scattering. Different types of stable aggregates of colloidal particles are revealed in both fluids. The addition of PEG results in a reorganization of the structure of the aggregates: the initial comparatively small and compact aggregates (about 40 nm in size) are replaced by large (more than 120 nm in size) fractal‐type structures. It is postulated that these large structures are composed of single magnetite particles coated with PEG, which replaces sodium oleate. Micelle formation involving free sodium oleate is observed in both fluids. The structures of the fluids remain unchanged with increasing temperature up to 343 K. New and specific possibilities of SANS contrast variation with respect to multicomponent systems with different aggregates are considered.