Chemical and Biological Engineering ETDs

Publication Date

7-12-2014

Abstract

The properties of magnetic nanoparticles vary dramatically with size, so reproducibly controlling size is critical for practical applications. This is particularly true when moving into clinical settings, where regulatory approval requires demonstrated reproducibility in efficacy that can only be achieved with excellent size control. A number of methods for the synthesis of magnetic nanoparticles have been published, although the thermal decomposition of iron(III) precursors in organic solvents has been shown to yield high quality particles with low shape and size dispersity. Currents methods lack reproducibility resulting from non-stoichiometric starting materials, and reliance on reaction parameters, such as temperature ramp rate, that are nearly impossible to replicate between syntheses. Limited control of particle size has been demonstrated, though no truly size-tunable synthetic method has been proposed. Here, we endeavor to remove the sources of reproducibility in the existing methods and achieve size control of synthesized particles while maintaining narrow shape and size dispersity. Further, we endeavor to understand the physical mechanisms by which the control of size is achieved. Here, we detail two alternative approaches to the synthesis of an iron(III) precursor containing a known quantity of iron. These materials are further evaluated for use in the preparation of high quality iron oxide nanoparticles with high magnetic saturation values. Existing synthesis methods are also evaluated, leading to the development of a novel synthetic method that yields tunability of sizes over a broad range with nanometer precision and nearly uniform size and shape dispersity. By manipulating reaction parameters such as temperature and reagent concentration, the kinetics of the reaction can be controlled, revealing new insights into the growth of particles in a highly supersaturated monomer solution. We expect that our approach will resolve the challenges associated with the reproducible synthesis of spherical magnetite nanoparticles with low shape and size dispersity, and provide scalability required to meet commercial demand.

Keywords

Magnetite, nanoparticle, iron oleate, iron oxide, wustite, magnetometry, superparamagnetic, oleic acid, thermolysis

Sponsors

The body of research described in this dissertation was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and Engineering. HRTEM imaging and XRD/SAXS measurements were performed courtesy of the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energys National Nuclear Security Administration under Contract DE-AC04-94AL85000.'

Document Type

Dissertation

Language

English

Degree Name

Chemical Engineering

Level of Degree

Doctoral

Department Name

Chemical and Biological Engineering

First Committee Member (Chair)

Datye, Abhaya

Second Committee Member

Adolphi, Natalie

Third Committee Member

Huber, Dale

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