Date of Graduation

5-2019

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Degree Level

Graduate

Department

Mechanical Engineering

Advisor/Mentor

Huitink, David

Committee Member

Couvillion, Rick J.

Second Committee Member

Chen, Jingyi

Keywords

Induction Heating; Inter-particle behavior; Iron Oxide Nanoparticles; Magnetic Hyperthermia; Nanoparticle Clustering; SANS

Abstract

Due to their multi-functional nature, iron oxide nanoparticles present themselves in a myriad of scientific disciplines, but perhaps the most interesting property of these nanomaterials can be seen in their immense thermal response under the influence of alternating magnetic fields. Currently popularized as an alternative cancer treatment through localized hyperthermia, iron oxide nanoparticle induction heating presents an interesting physical phenomenon that distinguishes itself from macroscopic induction heating. Understanding how a single spherical particle behaves is relatively simple and remains well documented; however, magnetic interactions of a single particle often extend over many length scales, affecting numerous neighboring particles in the local vicinity. Inter-particle interactions play a significant role in the collective heating response of magnetic nanoparticle colloids, and their effect on heating efficacy remain inadequately addressed and widely debated amongst the scientific community. Submitted in partial completion of the requirements for a Master of Science in Mechanical Engineering, the thesis herein describes an investigation into particle characteristics that govern the collective heating response and nanoparticle clustering, such as capping chemistry and environmental factors. Unique characterization techniques, such as small angle neutron scattering were utilized to observe the extent of these interactions for different types of structurally different nanoparticles, as well as how each of the parameters affected the induction heating response. In situ measurements with small angle neutron scattering provided a glimpse of the geometry and size extent of the large-scale nanoparticle structures formed during induction heating; analysis of their dimension determined the spherical clusters extended well into the micron-range. Calorimetric measurements gathered under the influence of an alternating magnetic field exhibited the nanoparticles’ dependence on mean inter-particle spacing and the role inter-particle interactions have on the efficiency of the nanoparticles. Analysis in a saline environment showcased the effect of local electrolytes on the stability and thermal performance of surfactant-capped iron oxide nanoparticles. With the accumulation of multiple types of characterization data mainly examining the colloidal behavior of the nanoparticles, this study attempts to understand the deep-rooted dependence of nanoparticle induction heating efficiency on inter-particle behavior.

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