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Magnetic Polystyrene Nanoparticles with a High Magnetite Content Obtained by Miniemulsion Processes
Author(s) -
Ramírez Liliana P.,
Landfester Katharina
Publication year - 2003
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200290052
Subject(s) - miniemulsion , magnetite , polystyrene , superparamagnetism , chemical engineering , materials science , magnetic nanoparticles , polymerization , polymer chemistry , nanoparticle , polymer , composite material , nanotechnology , magnetization , metallurgy , physics , quantum mechanics , magnetic field , engineering
The encapsulation of high amounts of magnetite into polystyrene particles can efficiently be achieved by a new three‐step preparation route including two miniemulsion processes. In the first step, a dispersion of oleic acid coated magnetite particles in octane is obtained. In the second step, magnetite aggregates in water are produced in a miniemulsion process by using sodium dodecyl sulfate (SDS) as surfactant. In the third step, the dispersion with the magnetite aggregates which are covered by an oleic acid/SDS bilayer were mixed with a monomer miniemulsion and a second miniemulsion process, an ad‐miniemulsification process, is used to obtain full encapsulation. After polymerization, polymer encapsulated magnetite aggregates were obtained. Characterization by thermogravimetry, preparative ultracentrifugation, and transmission electron microscopy showed that up to 40% magnetite could be encapsulated resulting in particles with a high homogeneity of the magnetite content. Magnetometry measurements reveal that the included iron oxide aggregates still consist of separated superparamagnetic magnetite particles.Transmission electron micrograph for magnetite polystyrene particles (Latex‐1).