Field induced formation of mesoscopic polymer chains from functional ferromagnetic colloids

Jason J. Benkoski, Steven E. Bowles, Bryan D. Korth, Ronald L. Jones, Jack F. Douglas, Alamgir Karim, Jeffrey Pyun

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


The assembly and direct imaging of ferromagnetic nanoparticles into one-dimensional mesostructures (1-D) are reported. Polymer-coated ferromagnetic colloids (19 nm, 24 nm) were assembled at a crosslinkable oil-water interface under both magnetic field induced and zero-field conditions and permanently fixed into 1-D mesoscopic polymer chains (1-9 μm) in a process referred to as Fossilized Liquid Assembly (FLA). In the FLA process, nanoparticle chains were fixed at the oil interface through photopolymerization, enabling direct visualization of organized mesostructures using atomic force microscopy. Using the FLA methodology, we systematically investigated different conditions and demonstrated that dispersed ferromagnetic colloids possess sufficient dipolar interactions to organize into mesoscopic assemblies. Application of an external magnetic field during assembly enabled the formation of micron-sized chains which were aligned in the direction of the applied field. This universal methodology is an attractive alternative technique to cryogenic transmission electron microscopy (cryo-TEM) for the visualization of nanoparticle assembly in dispersed organic media.

Original languageEnglish (US)
Pages (from-to)6291-6297
Number of pages7
JournalJournal of the American Chemical Society
Issue number19
StatePublished - May 16 2007

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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