Modelling Microstructure Evolution Phase Separation

我们的研究计划旨在开发计算模型，将描述相行为的热力学与支化聚合物的化学反应和分子运动的动力学结合起来。我们的工作是由最近的实验观察，目前缺乏物理解释的动机。这种解释是设计和优化新配方的关键。最令人惊讶的是，正如提议者在最近完成的Solvay资助的博士项目中进行的中子散射实验所揭示的那样，在液态的共混物中存在预先存在的纳米级结构。这样的结构似乎与另一个令人惊讶的观察相关，由里昂的索尔维/CNRS联合研究中心的合作者，即共混物继续显着演变，即使在形成网络之后，在长度尺度上与相分离前的结构相对应。这些观察结果都不能用现有的模型来解释，这些模型未能捕捉到分支如何影响热力学和动力学的物理后果。我们最近开发了一种Monte Carlo模型，能够模拟支化/线性聚合物的共混物，并证明它能够预测平衡现象。我们在这个项目中的目标是建立在这项工作：1。将模型从平衡过程扩展到非平衡过程，以模拟相分离动力学并预测共混物的流动响应。后者是必不可少的比较理论与实验进行固化样品在威尔顿。使用Monte Carlo模型参数化粗粒度方法，用于模拟界面存在时的结构和结构演变，这在共混物浸渍到碳纤维中时特别重要.通过使用图形处理单元的并行化显著提高代码效率，以便为大型系统建模更长时间的过程，使结果更具实验相关性。4.为了支持中子散射实验，正在索尔维与里昂的Long教授的研究小组合作进行，这对验证和改进我们的模型至关重要。

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.