Tailoring self-sorting behavior in multicomponent supramolecular systems using functional dipeptide diastereomers

Guan, Qingwen (2024) Tailoring self-sorting behavior in multicomponent supramolecular systems using functional dipeptide diastereomers. PhD thesis, University of Glasgow.

Abstract

Multi-component supramolecular systems are essential for tailoring materials to meet specific application needs, mimicking natural processes where molecular self-sorting forms complex, multi-layered structures within cells for vital functions. In these systems, self-sorting is carefully controlled to program desired properties into the final product, balancing the retention of key characteristics with the introduction of new structural or functional properties. While these selfsorted systems are promising for creating advanced materials, their complexity makes them difficult to fully understand and control.

In Chapter 2, we extensively employed characterization techniques such as small-angle scattering (SAS), cryo-transmission electron microscopy (cryo-TEM), rheology, and various spectroscopic methods to investigate the self-sorting behavior of mixtures of diastereoisomers of naphthyl diphenylalanine. We examined how their composition ratio affects the properties of functionalized dipeptide hydrogels in different phases. These studies demonstrated how significant structural features and interactions at varying ratios influence the physical and optical properties of gels, such as viscosity, gelation time, turbidity, and spectral characteristics.

In Chapter 3, we delved deeper into stacking patterns and their impact on the properties of a library of naphthyl dipeptide diastereomeric mixtures. Using differently substituted naphthalene rings, we developed multicomponent systems with varying self-assembled nanostructures or gelation capabilities. Analysis at molecular, microscopic, and holistic levels revealed that each component within the two-component systems could independently form self-assembled nanostructures, thus exhibiting self-sorting behaviors at different scales. These findings illustrate that the peptide's stereochemistry plays a pivotal role in self-assembly, enabling the design of self-sorting, low molecular weight gel (LMWG) systems.

In Chapter 4, we described the optical properties of the dipeptide-based pre-gel solutions using advanced characterization methods such as synchrotron radiation circular dichroism (SRCD) and Mueller Matrix Polarimetry (MMP). MMP analysis captured comprehensive polarization data, confirming significant differences in molecular orientation and electronic interactions between homochiral and heterochiral systems. These findings indicate that mixing diastereoisomers alters the optical properties, affecting circular birefringence and dichroism, and suggesting shifts in chiral order and molecular interactions.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Supported by funding from the China Scholarship Council (grant no. 202006440011).
• Subjects: Q Science > QD Chemistry
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Adams, Professor Dave
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84811
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 16 Jan 2025 09:43
• Last Modified: 16 Jan 2025 11:07
• Thesis DOI: 10.5525/gla.thesis.84811
• URI: https://theses.gla.ac.uk/id/eprint/84811

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