Title page for ETD etd-11012010-115420

Type of Document Master's Thesis
Author Mejia-Ariza, Raquel
Author's Email Address raquelmejia27@gmail.com
URN etd-11012010-115420
Title Design, Synthesis, and Characterization of Magnetite Clusters using a Multi Inlet Vortex Mixer
Degree Master of Science
Department Macromolecular Science and Engineering
Advisory Committee
Advisor Name Title
Davis, Richey M. Committee Chair
Riffle, Judy S. Committee Co-Chair
Edgar, Kevin J. Committee Member
  • Rapid nanoprecipitation
  • magnetite clusters
  • Multi Inlet Vortex Mixer
  • poly (ethylene oxide)
  • contrast agent
  • steric stabilization
  • poly (propylene oxide)
Date of Defense 2010-10-18
Availability unrestricted

Superparamagnetic nanoparticles have potential applications in targeted drug delivery and as magnetic resonance imaging contrast agents. Magnetite clusters are of particular interest for these applications because they provide higher magnetic flux (under a magnetic field) than individual magnetite nanoparticles, are biocompatible, and their size and compositions can be controlled. This thesis involves the controlled synthesis and characterization of clusters composed of magnetite nanoparticles stabilized with an amphiphilic block copolymer. It outlines a method to design and form well-defined and colloidally stable magnetite clusters. A Multi Inlet Vortex mixer (MIVM) was used because it is a continuous process that yields particles with relatively narrow and controlled size distributions. In the MIVM, four liquid streams collide under turbulent conditions in the mixing chamber where clusters form within milliseconds. The formation of magnetite clusters was studied in the presence of amphiphilic block copolymers containing poly (ethylene oxide) to provide steric stabilization and control of size distributions using flash nanoprecipitation.

First, the mixer was tested using β-carotene as a model compound to form nanoparticles stabilized with an amphiphilic triblock copolymer poly(propylene oxide)-b-poly(ethylene oxide) (F127) at different Reynolds numbers and supersaturation values. Size analysis was done using dynamic light scattering and nanoparticle tracking analysis techniques. The cluster structure was studied using electron microscopy and magnetite compositions were measured using thermogravimetric analysis. Finally, the stability of magnetite clusters was studied over time and the effect of an applied magnetite field on the colloidal stability was investigated.

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