JiHyeon Hwang

Date of Award

Spring 2023

Document Type

Open Access Dissertation


Chemistry and Biochemistry

First Advisor

Chuanbing Tang


A polymer consists of a large number of monomer units, which can be obtained naturally or via a chemical process called polymerization. Polymers are important materials that are used in our daily life. Life would not be possible without these polymers, either from plant biomass or petroleum-derived synthetic polymers. The substitution of petroleum-derived to biomass-based polymers has been highlighted to mitigate adverse environmental impact. However, the use of bio-based polymers is still a significant challenge for more demanding applications. In this dissertation work, the engineering of both bio-based and synthetic polymers and their properties are investigated.

In Chapter 1, the overall background of bio-based polymers and synthetic metallopolymers, especially metallocene-containing polymers, and their materials engineering are discussed. Additionally, the content of antimicrobial polymer is covered.

The first part of this dissertation focuses on the applications and design of polymeric materials derived from biomass. In Chapter 2, the development of lignin-based superabsorbent materials based on the oxidization of kraft lignin using chelator-mediated Fenton (CMF) chemistry and radical crosslinking polymerization are discussed. CMF chemistry is used to modify lignin to make it hydrophilic, thus allowing the production of lignin-based hydrogels in aqueous solutions. This water-soluble lignin allows the fabrication of superabsorbent materials with tunable physical and chemical compositions.

The second part of this dissertation focuses on the applications and design of metallopolymers. In Chapter 3, polymers containing cobaltocenium units at the side chain are developed to prepare double-network (DN) hydrogels via sequential ring-opening metathesis polymerization (ROMP) and free radical polymerizations (FRP). Moreover, incorporating boronic acid moieties further improves the antibacterial efficacy of penicillin G conjugated metallopolymers.

In Chapter 4, a series of metallopolymer-antibiotic combinations are prepared to understand their actions on bacteria and revitalize existing the efficacy of antibiotics. Cobaltocenium-based metallopolymers are polymerized from cobaltocenium methacrylate monomers using a RAFT polymerization method followed by ion exchange from PF6 - to Cl-to carboxylate anions, β-lactam antibiotics. The power of cobaltocenium moieties provides a library of cationic metallopolymer combinations, where they are mixed with different classes of antibiotics via ionic pair or physical mixing.

Finally, a summary of this dissertation and an outlook for future research are presented in Chapter 5.

Available for download on Thursday, May 15, 2025

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