Structure, Dynamics and Interactions of Nanofibres in Dilute Hydrodynamically Forced Systems

The ever increasing threat from climate change has spurred the demand for innovative, sustainable materials that could reduce our dependence on fossil fuels. Dispersions of cellulose nanofibrils (CNFs), derived from wood, can be spun into filaments that exhibit favourable mechanical properties. However, the structure, dynamics and interactions of the CNFs during the spinning process, which greatly affect the properties of the resulting filament, have yet to be fully understood. The optical properties of CNF can be used to determine structural information. The most complete optical characterisation technique is Mueller matrix polarimetry. In this method, a 4×4 matrix, which fully describes the material’s effect on an incoming state of light is derived. This matrix contains information about the retardance, depolarisation and birefringence of the material. We hope to construct such a polarimeter to determine the structure and dynamics of CNF in confined flows.  As a complement to the Mueller matrix polarimetry, the use of Cryo-TEM tomography has the potential to yield a three-dimensional snapshot of the structure and interactions of the fibrils. We hope to produce tomograms of CNF dispersions as well as aggregates. The structural information would be used for comparison with Mueller matrix polarimetry as well as other techniques, such as flow-stop and SAXS.