Dissertations, Theses, and Capstone Projects

Date of Degree

2-2023

Document Type

Dissertation

Degree Name

Ph.D.

Program

Chemistry

Advisor

Donna McGregor

Committee Members

Rein Ulijn

Gustavo Lopez

Miguel Modestino

Benjamin Burton-Pye

Pamela Mills

Subject Categories

Biochemical and Biomolecular Engineering | Curriculum and Instruction | Higher Education and Teaching | Materials Chemistry | Other Chemistry

Keywords

Tripeptide, Fmoc, Histidine, Aspartic Acid, Beta Sheets, Proton Wire

Abstract

The increasing demand for clean and sustainable energy has driven forward rapid improvements in polymer-electrolyte fuel cells and the use of ion-conducting polymers (ionomers) as proton exchange membranes and catalyst binders. While perfluorinated electrolytes have been commercially used as conductive membranes for nearly four decades, a new class of sustainable, conductive materials has emerged, inspired by the efficiency of charge transport processes in biological systems. These molecules, knows as peptide amphiphiles (PAs), have gained popularity as building blocks for the bottom-up fabrication of nanomaterials through supramolecular self-assembly. Supramolecular nanostructures, often in the form of hydrogels, are held together via non-covalent interactions and have various potential applications in biomedicine, nanotechnology, food science, cosmetics, and more recently advanced electronic devices. PAs self-assemble into nanofibers, as a result of aromatic interactions and hydrogen bonding. This has prompted their use in proton transport, and many have exhibited conductivity that is dependent on the relative humidity of the environment. The naturally occurring amino acid, histidine, contains an amphiprotic side chain, imidazole, that has been shown to participate in proton conduction via the Grotthuss shuttling mechanism.

This thesis demonstrates the development of short, aromatic peptide amphiphiles containing histidine and the ability of histidine-based fibrous nanostructures to participate in proton conductivity.

This work is embargoed and will be available for download on Saturday, February 01, 2025

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