Date of Award

Spring 3-2023

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Yoan C. Simon

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Robson F. Storey

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Xiaodan Gu

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Derek L. Patton

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Jeffery S. Wiggins

Committee Member 5 School

Polymer Science and Engineering

Abstract

The introduction of novel dynamic exchange chemistries into polymer chains and networks has shown great potential of giving next generation polymeric materials. Within the scope of this thesis, dynamic chemistry is employed to realize single-chain nanoparticles, vitrimer networks, bottlebrush and comb polymers. CHAPTER I provides a broad introduction to the topics at hand, focusing upon the techniques utilized to achieve such materials with relevant literature and understanding of the techniques and architectures explored. CHAPTER II focuses upon the synthesis of single-chain nanoparticles via a copolymerization of polyisobutylene macromonomers with norbornene monomers equipped with pendant anthracene moieties. Through this work, the aliphatic non-polar polyisobutylene chains allowed for the collapse of the chain upon photodimerization of the pendant anthracene. This photodimerization reaction could be driven further upon the introduction of a solvent, i.e. n-hexane, selective only for the polyisobutylene side-chains.

CHAPTER III pivots to a separate unique reactivity focusing upon dynamic covalent chemistries through the diketoenamine linkage. Our vitrimers, or associatively exchanging networks, were realized through a two-step process whereby diketoenamine linkages are synthesized before the formation of the polymer network. Further, the decoupling of these steps has allowed for the polymer network to be formed in an on-demand method. These networks experimentally showed a low glass transition temperature but had a relatively high thermodynamic threshold for exchange to occur. The networks further showed degradability capabilities through the introduction of small molecule amines and could be reprocessed back into a useful network material. CHAPTER IV takes the concept of these diketoenamines and applies them to architecturally intriguing structures, i.e. bottlebrush and comb polymers. The diketoenamine linkage was used as a reactive moiety to functionalize the chain-end of hemitelechelic polymers with polymerizable head groups. These functional macromonomers were then polymerized via ring opening metathesis polymerization generating a series of bottlebrush polymers. Intriguingly, the triketone linkage precursor and the diketoenamine linkage were both found to be orthogonal to the ring opening metathesis polymerization providing functionalized linear polymers. These functional polymers were then explored for their reactivity with primary amines.

Finally, CHAPTER V provides a summary of the work performed within each chapter of this thesis and then provides thoughts upon the next steps one might take in the realization of novel functional polymeric materials.

Available for download on Friday, March 07, 2025

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