Developing methods to monitor and analyse fibre formation in wet-spinning using advanced materials characterisation methods

Filament coagulation is the core-process of wet-spinning (and coagulated 3D printing). Wet-spinning is one of the major techniques that can be used to produce fibres (viscose, regenerated silk, etc.). While the technique has been employed for decades, the tools that provide control or knowledge of the filament coagulation process (kinetics, thermodynamics) are inadequate to wet-spinning being efficiently applied to novel materials and coagulants. This hinders progress in developing novel fibre compositions, especially if encompassing complex mixtures or natural components, and delays the move from traditionally-employed harmful chemistries.

The models and analysis methods available in literature to monitor the coagulation of a filament are either mostly theoretical or quite rudimental, but they are typically developed ad-hoc and display large margins of error and low universality.

This project will result in:

a novel, simplified, method for monitoring and predicting filament solidification in wet-spinning environments;
greater knowledge in fibre formation processes and the processing parameter envelope.

This project will contribute to the Institute’s efforts to develop sustainable methods to produce and recycle textile fibres and materials and to develop novel fibre formulations. The short polymer fibres team has recently been developing a SANS/SAXS method which, combined with HNMR may provide a quantitative and structural method to monitor, model and predict solidification of a polymer dope in a coagulant. It is proposed that similar techniques be applied in this PhD, with a focus on the spinning of natural proteins.

The significance of this project lies in its aim to provide simple and widely-applicable tools to predict and monitor solidification of filaments in wet-spinning environments. The project will result in a tool-box for the experimenter who wishes to predict, model and test filament formation in wet-spinning, and will enable faster testing and development of novel wet-spinning combinations.

The student will study the thermodynamics (coagulant/polymer/solvent phase diagrams, rheology) and kinetics of polymer-solution coagulation through a combination of approaches such as wet-spinning, analytical techniques such as H1NMR, confocal microscopy and SANS/SAXS.

The student will:

develop and discover phase diagrams for a range of polymer/solvent/coagulant systems, including use of H1NMR, SANS/SAXS and rheological characterisation,
develop a mathematical model that includes refined diffusion coefficients and rheological information gathered in the physical model experiments,
test and validate the model using a variety of coagulant/solvent/polymer systems, with a focus on naturally-derived materials.

This project will result in:

a novel, simplified, method for monitoring and predicting filament solidification in wet-spinning environments;
greater knowledge in fibre formation processes and the processing parameter envelope.