Development of new low molecular weight gelators and studies on their self-assembly behaviour

Abstract

The field of supramolecular gels has received increasing attention for the past fifty years due to their versatility and multitude of applications. In the petrochemical industry in particular, they have been identified as powerful and environmentally friendly tools which can efficiently replace the current practices employed in the crude oil extraction processes.

An example of these are pyromellitamide-based organogels discovered by our laboratories in partnership with SynOil Fluids Inc. The synthesis optimisation, characterisation and viscosity properties for these soft materials are described herein. The gelation abilities of these molecules were analysed in depth and it was shown that they are very versatile, as they form soft materials with a variety of hydrocarbons, creating a lot of scope for industrial applications.

Modified aromatic and non-aromatic scaffolds were synthesised and analysed in the effort to understand the self-assembly phenomenon that leads to the formation of gels. A collection of aromatic molecules was designed by structurally modifying the pyromellitamide scaffold with emphasis on the amide-chains substituents. Similarly, series of non-aromatic molecules were designed by removing key features known to aid gelation. Structures with saturated and unsaturated six-membered ring cores were obtained before the ring was removed entirely to create linear bis-amides, bis-ureas, bis-thioureas and bis-carbamates. Generally, these compounds had very poor dynamic viscosity properties, reiterating the delicate relationship between structure and activity.
To prove this concept further, a novel class of diphenyl-based tetrasubstituted compounds was designed and developed. Their synthesis, characterisation and industry applications are described in detail. Similar to the pyromellitamide-type compounds, these structures form very strong gels, making characterising them a challenging task. Dynamic viscosity measurements were performed in depth mapping the structure-activity relationship.

Date of Award	27 Jun 2018
Original language	English
Awarding Institution	University of St Andrews
Supervisor	R Alan Aitken (Supervisor)