Scrolling, Braiding and Branching in Fibrous Soft Materials

Think about how useful braiding has been on the macroscopic scale in the context of the evolution of human society. The transformation of natural fibres into ropes, plaits and weaves has given rise to huge advances in construction, exploration, textiles and art. In biology the way in which fibre entangle is also hugely important. Tangled or entwined fibres are found in DNA and in serious protein misfolding diseases such as amyloidosis, and are responsible for the symptoms of old age. Fibre entanglement is also of huge industrial importance in polymer chemistry (entanglements create weak points that make your polythene bag tear, for example) and fibrous assemblies are found in gels, lubricants and creams (think hair gel, drilling 'mud', contact lenses and pill coatings, for example). In Nature fibres allow climbing plants to encircle a support according to quite subtle rules that are not readily apparent. Many of these fibrous assemblies occur chaotically and it is difficult to predict what the properties of the bulk material will be even with a good understanding of the fibrous components. This research project aims to create controlled, well-defined fibres whose evolution into complex (sometimes called 'emergent') assemblies can be studied in detail. We will examine how a fibre forms through aggregation of molecules and scrolling of molecular sheets, how it entwines through surface attachment and braiding, and how it branches through defect formation and entanglement, ultimately giving rise to the natural and everyday materials we are familiar with in the world around us.

This is a fundamental project designed to understand the detailed mechanism by which self-assembled organic fibrils are formed, how they mutually braid and entangle, how defects arise and what consequences these topological features have on their materials properties, particularly rheology. The rheological properties of soft materials such as gels impacts upon a broad range of industrial sectors in tremendous importance to the UK. For example, self-assembled gels can be used to control the solid form of pharmaceuticals. Solid form discovery and control in the context of pharmaceutical formulation is worth around £1tn globally. Gels such as guar gum are used as drilling fluids in the oilfield sector and the fundamental understanding from the present project offers long term prospects in improved gels for this application. Far more generally, fibrous materials and the materials that they form are involved with disease states such as the formation of amyloid fibrils, they underpin protein folding, structural tissue formation, resistant materials such as Kevlar, pharmaceutical formulation such as polymeric stabilisers of high solubility amorphous materials and domestic products such as contact lenses, hair gels and lithium grease. New fundamental understanding will engender materials with new properties and hence new economic opportunities.