Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Chemistry

Supervisor

Elizabeth Gillies

Abstract

Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multi-step monomer syntheses and the degradation products such as quinone methides or phthalaldehydes are potentially toxic to humans and the environment. We demonstrate here that polyglyxoylates can serve as a new and versatile class of self-immolative polymers. Polymerization of the commercially available monomer ethyl glyoxylate, followed by end-capping with a 6-nitroveratryl carbonate provides a poly(ethyl glyoxylate) that depolymerizes selectively upon irradiation with UV light. Via ozonolysis of corresponding fumaric or maleic acid derivatives, a series of different glyoxylates were synthesized and polymerized, providing polyglyoxylates with different physical properties. Furthermore, using a multifunctional end-cap that is UV-responsive and also enables the conjugation of another polymer block via an azide-alkyne "click" cycloaddition, amphiphilic self-immolative block copolymers were prepared and self-assembled into light responsive micelles for drug delivery. Lastly, stimuli-responsive end-caps other than those responsive to UV light were also installed at the termini of poly(ethyl glyoxylate) to achieve polyglyoxylates responsive to other stimuli. Overall, these strategies are expected to greatly expand the utility of self-immolative polymers by providing access for the first time to self-immolative polymers with tunable properties that can be readily obtained from simple monomers and which depolymerize into non-toxic products.

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