Date of Award

Spring 2023

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Morgan Stefik

Abstract

Polymer micelles have found significant uses in areas such as, energy storage devices, catalysis, opto-electronics, drug-delivery, oil additives, and nanoreactors. In many of these applications the overall micelle size (aggregation number) and chemical functionalization determines performance. To progress towards more advanced materials synthesized from the facile bottom-up approach with polymeric micelles the implementation and study of thermodynamic handles were investigated. Here the kinetic control of micelles was studied across a range of applications; independent control over micelle functionality, the spatial orientation of multiple metal oxide nanoparticles in mesoporous materials via self-assembly, and the use of small-angle neutron scattering (SANS) to study micelle kinetics.

These topics are addressed sequentially by chapter. In the second chapter the challenge of changing micelle corona chemistry without change to the aggregation number was accomplished. The use of kinetically-entrapped micelles in solution allowed for the systematic tuning of the corona acid content by locking in micelle size prior to functionalization. This new process opens avenues to independently the study the effects of micelle functionality without simultaneously observing variable micelle size. In the third chapter the ability to control multiple metal oxides via self-assembly for nanomaterials with advanced architectures was addressed. Novel structure-directing-agents were implemented to afford kinetic control of metal oxide nanoparticles through covalent interactions for materials with controlled interfaces from polymer micelles. The fourth chapter looks to better understand the kinetic processes of micelle homogenization via cavitation induced chain exchange. New instrumentation was developed to monitor in-situ mixing of micelles in otherwise kinetically trapped states. This process elucidated the dependence of polymer concentration and gas content of solvents during such events. Finally, in the fifth chapter the challenge of monitoring chain exchange in systems that undergo morphological transitions was addressed. Here a new model was presented with shifting reference patterns to be utilized with small-angle neutron experiments. Using simulated datasets, the capabilities of the new model were explored in comparison to alternative routes. As a collective these advancements in micelle research have expanded the scope of micelle control from a kinetics perspective.

Rights

© 2023, Taylor Larison

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