Graduation Year

2010

Document Type

Thesis

Degree

M.Ch.E

Degree Granting Department

Chemical and Biomedical Engineering

Major Professor

Vinay K. Gupta, Ph.D.

Committee Member

John T. Wolan, Ph.D.

Committee Member

Mark Jaroszeski, Ph.D.

Keywords

thermally-responsive, poly N-isopropylacrylamide, optical absorption, metallic, multilayered nanomaterial

Abstract

Gold nanoshells, a material generally composed of a core of silica surrounded by

a thin shell of gold, are of great interest due to their unique and tunable optical properties.

By varying the shell thickness and core size, the absorption and scattering properties are

greatly enhanced. The nanoshells can be made to absorb or scatter light at various

regions across the electromagnetic spectrum, from visible to the near infrared. The

ability to tune the optical properties of nanoshells allows for their potential use in many

different areas of research such as optical imaging, tumor ablation, drug delivery, and

solar energy conversion. The research in this thesis focused on the synthesis and

characterization of two novel gold nanoshell materials containing thermally-responsive,

organic-inorganic hybrid layers. One type of material was based on a two-layer particle

with a thermally responsive hybrid core of N-isopropylacrylamide (NIPAM)

copolymerized with 3-(trimethoxysilyl)propyl methacrylate (MPS) that was then coated

with a thin layer of gold. The second material was a three-layer particle with a silica

core, a thermally responsive copolymer of NIPAM and MPS middle layer and an outer

shell of gold. Various techniques were used to characterize both materials. Transmission

electron microscopy (TEM) was used to image the particles and dynamic light scattering

(DLS) was used to determine particle size and the temperature response. Additionally,

UV-Vis spectroscopy was used to characterize the optical properties as a function of

temperature.

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