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Magnetite/Polypyrrole Hybrid Nanocomposites as a Promising Magnetic Resonance Imaging Contrast Material
Author(s) -
Alves Kleber G. B.,
Andrade Cesar A. S.,
Campello Sergio L.,
de Souza Ricardo E.,
de Melo Celso P.
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.38481
Subject(s) - polypyrrole , materials science , nanocomposite , magnetite , nanoparticle , polymerization , aqueous solution , chemical engineering , magnetic nanoparticles , ferrofluid , emulsion polymerization , nuclear magnetic resonance , nanotechnology , polymer , composite material , chemistry , organic chemistry , magnetic field , physics , quantum mechanics , engineering , metallurgy
We have prepared magnetite nanoparticles (Fe 3 O 4 _NPs) almost spherical in shape with average particle size of 10 nm and successfully encapsulated them in an envelope of polypyrrole (PPY) chains via an emulsion polymerization route using sodium dodecyl sulfate as surfactant. The resulting PPY‐coated Fe 3 O 4 _NPs (Fe 3 O 4 _NPs/PPY) suspensions were stable with particles exhibiting a triangular prismatic morphology and an average diameter below 100 nm. In fact, all colloidal solutions were stable in aqueous media with typical ζ‐surface potential values of −33.9 mV (Fe 3 O 4 _NPs) and −20.0 mV (Fe 3 O 4 _NPs/PPY). Although X‐ray diffraction studies revealed the presence of a magnetic phase Fe 3 O 4 , the identified diffraction peaks are consistent with the presence of a spinel structure of magnetite. A ferromagnetic behavior, such as lower coercive force ( H c = 0.065 T), was observed for all magnetic nanoparticles examined. The 1 H NMR relaxation times T 1 and T 2 of selected Fe 3 O 4 _NPs/PPY samples were also measured and their relaxivities r 1 (1.1 s −1 mM −1 ) and r 2 (61.9 s −1 mM −1 ) compare favorably to those of contrast agents commercially used in human examinations. We suggest that the present results indicate that these hybrid nanocomposites are promising materials for the development of a platform of specialized contrast agents for 1 H Magnetic Resonance Imaging. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013