Polymer-coated ferromagnetic colloids from well-defined macromolecular surfactants and assembly into nanoparticle chains.
A novel synthetic route to polymer-coated ferromagnetic colloids of metallic cobalt has been developed. Well-defined end-functional polystyrenes were synthesized using controlled radical polymerization and used as surfactants in the thermolysis of dicobaltoctacarbonyl to afford uniform ferromagnetic nanoparticles. The presence of the polymer shell enabled prolonged colloidal stability of dispersions in a wide range of organic solvents and formed glassy encapsulating coatings around ferromagnetic cores in the solid state. These polymer-coated colloids assembled into robust, micron-sized nanoparticle chains when cast onto supporting surfaces due to dipolar associations of magnetic cores. Hierarchical assemblies were also prepared by blending polystyrene-coated cobalt colloids with larger silica beads.
Korth
Bryan D
BD
Department of Chemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85752, USA.
Keng
Pei
P
Shim
Inbo
I
Bowles
Steven E
SE
Tang
Chuanbing
C
Kowalewski
Tomasz
T
Nebesny
Kenneth W
KW
Pyun
Jeffrey
J