Modelling Microstructure Evolution Phase Separation

Our research program aims to develop computational models that couple the thermodynamics describing the phase behaviour with the kinetics of both chemical reactions and the molecular motion of branched polymers. Our work is motivated by recent experimental observations that currently lack a physical interpretation. Such interpretations are key to the design and optimisation of new formulations. Most surprisingly, as revealed by neutron scattering experiments conducted by the proposer in a recently completed Solvay funded PhD project, there are pre-existing nanoscale structures in the blend in the liquid state. Such structures appear to be correlated with another surprising observation, by collaborators at the joint Solvay/CNRS research centre in Lyon, that the blends continue to evolve significantly, even after the formation of a network, at length-scales corresponding with that of the pre-phase separated structures.

Neither of these observations can be explained by existing models, which fail to capture the physical consequences of how branching impacts on the thermodynamics and kinetics. We have recently developed a Monte Carlo model that is able to model blends of branched/linear polymers and demonstrated that it is able to predict equilibrium phenomena. Our aims in this project are to build upon this work:

1. To extend the model from equilibrium to non-equilibrium processes in order to model the kinetics of phase separation and predict the flow response of the blends. The latter is essential for comparing theory with experiments conducted on curing samples at Wilton.
2. To use the Monte Carlo model to parameterise coarser grained methods for modelling structure and structure evolution in the presence of interfaces, which is of particular importance when the blends are impregnated into carbon fibres.
3. To significantly increase code efficiency through parallelisation using Graphical Processing Units, in order to model longer time processes for larger systems, making results more experimentally relevant.
4. To support neutron scattering experiments, being conducted at Solvay in collaboration with the research group of Professor Long in Lyon, which will be essential to verify and refine our modelling.