Date of Award

5-10-2026

Date Published

June 2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor(s)

Mathew Maye

Second Advisor

Ramesh Raina

Keywords

Nanomaterial Assembly;Polymer Functionalization;Smart Nanomaterial Synthesis;Stimuli-Responsive Polymers;Surface Chemistry

Subject Categories

Chemistry | Physical Sciences and Mathematics

Abstract

The modification of nanoparticles with combinations of low critical solution temperature (LCST) polymers and polyelectrolyte (PE) layers is studied. Three n-isopropylacrylamide-co-acrylamide polymers were synthesized in which charges could be varied from neutral, to negative or positive by way of incorporating poly acrylic acid (pAAc) or poly 4-vinylpyridene (p4VP) units. Polymerization centered around a disulfide initiator, which when reduced produced two polymer chains and a convenient linkage to gold NPs (NPs). The resulting LCST-NPs conjugates possessed sharp phase changes at critical temperatures (TC), while the incorporation of pAAc or p4VP allowed for tuneable charges and pH sensitivity. Studies with 1H-NMR and FTIR confirmed the polymer synthesis and NP functionalization, while UV-Vis and DLS monitored pH and temperature sensitivity by observing changes in surface plasmon resonance (SPR), hydrodynamic diameter (Dh), and zeta potential. The isoelectric point of each system was determined, as was the relative buffering capacity of the LCST-NP, which indicated only a few LCST polymers per NP, which limited stability and charge. To overcome this, PE layers were deposited in a layerby-layer (LbL) manner forming PE/LCST-NPs conjugates, which had layer dependent charge and improved stability, while retaining LCST properties of the base layer.

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Open Access

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