Synthesis of Polycarbamate‒based Nanoassemblies and Previously Inaccessible Polyglyoxylates
Abstract
Self-immolative polymers (SIPs) are a subclass of degradable polymers that can be triggered to depolymerize when exposed to a specific stimulus. The main advantages of SIPs are the controlled and predictable depolymerization, signal amplification, and tunability of the polymer regarding which stimuli it responds to. The work presented in this thesis details the synthesis, characterization, and applications of two different families SIPs: polycarbamates (PCBs) and polyglyoxylates (PGs). PCBs are known to have depolymerization rates that are sensitive to environmental conditions surrounding them. In efforts to modify the depolymerization, PCB was incorporated into amphiphilic diblock copolymers, first with multi-stimuli-responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA). Evaluation of the ultraviolet (UV) light-responsive depolymerization behaviour under different pH and temperature conditions indicated that temperature was determining factor driving increased depolymerization rates. Secondly, PCB was incorporated into a block copolymer with thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm), which responds at lower temperatures than PDMAEMA. However, this system appeared to aggregate irreversibly in solution even at lower temperatures, making it problematic in experiments. PGs are one of the newer classes of SIPs. Previously, many glyoxylate monomers were inaccessible because of problems synthesizing the monomers or achieving large volumes of sufficiently pure monomers for polymerization. Overall, only a few new monomers were successfully polymerized, only yielding lower degrees of polymerization compared to PEtG. To expand the usefulness of this family, previously inaccessible PGs were achieved through a transesterification reaction with PEtG. A family of alkyl PGs and functional PGs were created, with the latter being used in further post-transesterification modification. Combined this work represents a significant advance in the synthesis and applications of SIPs.