Controlling Interactions and Functionality of PDI-Based Compounds by Targeted Chemical Modification

Abstract

Supramolecular polymers are unique compounds that find application in multiple fields of functional materials and polymer science. Given their fascinating properties, including self-healing abilities and tuneability after polymerisation, this class of materials shows potential to contribute solutions to a plethora of current challenges. Despite the large amount of research carried out, complete understanding of the influence of various chemical modifications on the properties of the resulting aggregates is still lacking. The integration of supramolecular polymers into functional materials led to the development of supramolecular adhesives, overlapping with the discipline of bio-based materials. Nonetheless, optimisation is required to fully utilise the capacity of supramolecular interactions to drive advances in materials for biological applications, specifically for surgical adhesives. The resulting improvements in performance may lead to new applications and decreased complications while increasing ease of surgical procedures in a range of settings.
The work conducted in this thesis explores novel strategies to optimise and tune supramolecular interactions for novel materials – with the final aim to implement and apply such materials as surgical adhesives. A bottom-up approach was chosen: the initial work in this project focussed on supramolecular chemistry and the effect of distinct chemical alterations on the optoelectronic and self-assembly properties. The gained knowledge was then transferred into the development of superior surgical adhesives in the second part of the project.
Project I presents a fundamental, comprehensive synthetic study into the self-assembly behaviour of perylene-based supramolecular polymers. The effects of various chemical modifications of perylene diimides on the self-assembly and optoelectronic properties were investigated. Specifically, modification by targeted thionation of the perylene core, modification of the bay positions by bromination and N-annulation were explored. A variety of changes and influences on the intramolecular interactions were observed and reported.
Project II built on the extensive synthetic knowledge acquired in Project I, and was used to demonstrate routes to novel designed supramolecular adhesives. Initial research included the investigation of ideal starting materials for the desired application, followed by exploiting the effects of branching and incorporation of perylene moieties into these functional materials. This approach resulted in significantly improving the performance of the obtained bio-adhesives, outperforming commercial materials.
Overall, the approaches developed in this thesis act as a foundation for the symbiosis of fundamental organic chemistry, supramolecular polymers, self-assembly and functional materials and their use in multiple domains.

Date of Award	23 Aug 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Charl F J Faul (Supervisor)