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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2017

Month Degree Awarded

February

First Advisor

Gregory Tew

Subject Categories

Other Cell and Developmental Biology | Polymer and Organic Materials | Polymer Chemistry

Abstract

This dissertation focuses on two distinct projects: the synthesis and design of novel cell penetrating peptides mimics (CPPMs), and the implementation of the thiol-ene click reaction to generate new polymer architectures and chemistries. Guanidinium-rich CPPMs were generated through both ROMP and RAFT polymerizations, allowing for a comparison to be made across polymer backbone chemistries with respect to both siRNA and protein cellular internalization. A particularly effective methacrylate derived block copolymer was able to deliver siRNA to nearly an entire Jurkat T cell population.

The thiol-ene reaction was implemented initially within the context of improving material design for solid polymer electrolytes (SPEs), specifically lithium ion separators. Synthesis of styrene-ethylene oxide multiblock copolymer electrolytes by the combination of telechelic di-thiol and di-norbornene polymers was performed. Morphology and conductivity were assessed as a function of conducting block volume fraction, with encouraging results and robust conductivities above a PEO volume fraction of 0.5. Flory-Huggins interaction parameters were also estimated and compared to literature projections.

New SPE chemistries utilizing thioethers, sulfoxides, and sulfones were also synthesized through the step-growth polymerization of various di-ene and di-thiol monomers. When doped with lithium ions, these materials demonstrated comparable conductivities to PEO, a benchmark SPE, and could be tuned to eliminate crystallization, a severe drawback of PEO at lower temperatures. These SPEs were also strengthened by polystyrene incorporation, resulting in block copolymer materials that demonstrated a room temperature storage modulus of 0.1 GPa, while maintaining high levels of conductivity. Finally, the universality of the thiol-ene polymerization was demonstrated by the generation of main-chain carbonate, main-chain zwitterion, and side-chain diol polymers. Similarly to the above SPE materials, these polymers contained a thioether functional group that could selectively be oxidized to yield either a sulfoxide or sulfone, without degrading the polymer or affecting the incorporated functional groups. The research described in this dissertation is broad-reaching in the field of polymer science and beyond, covering numerous applications and techniques, and demonstrating improvements upon standard applied materials.

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