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Date Permissions Signed

5-28-2019

Date of Award

Spring 2019

Document Type

Masters Thesis

Department or Program Affiliation

Chemistry

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Emory, Steven R.

Second Advisor

Rider, David A. (Materials scientist)

Third Advisor

Bao, Ying (Materials scientist)

Abstract

In this study, pH-responsive microgel particles, comprised of 2-vinyl pyridine (P2VP) and styrene (PS), are explored as scaffolds to assemble metallic nanoparticles (NPs) for ultrasensitive detection strategies. Microgel particles serve as size-tunable scaffolds to assemble metal (silver or gold) NPs for surface-enhanced Raman scattering (SERS) vibrational spectroscopy. The high sensitivity of SERS arises from the enormous enhancement of the Raman scattering cross sections of molecules adsorbed to roughened metal surfaces, such as metal NPs. Using a sterically stabilized latex of random copolymers of PS and P2VP (PSxP2VPy), this polymer is capable of transitioning to a microgel state through acid-base titration. This effect can be used to manipulate the interparticle spacing between adsorbed metal NPs in order to optimize SERS enhancement. The size of these metal NPs, usually gold or silver (Au NPs or Ag NPs), can also be tuned to further optimize SERS enhancement. These microgel-NP composites are characterized and their pH-responsive behavior is demonstrated to be reversible in both bulk SERS and single-particle SERS analyses.

Type

Text

Keywords

polymer, SERS, SERRS, pH

Publisher

Western Washington University

OCLC Number

1103670736

Subject – LCSH

Microgels; Nanoparticles; Silver; Gold; Raman effect, Surface enhanced; Raman spectroscopy; Nanostructured materials

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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