Simulations to Probe Structure and Mobilities of Poly electrolyte Multilayer Systems of variable Size

在上一个资助期，我们通过原子模拟和粗粒度模拟对少量聚电解质多层膜的内部结构和动力学进行了深入的研究。我们所获得的结果使我们了解了质子交换膜的一些重要特征，特别是关于静电相互作用和水的扩散，但也指出了需要一个更精细的粗粒度模型。我们在下一个资助期的第一个目标是开发和测试这样一个粗粒度模型，使用实验数据和原子模拟的结果作为参考，原子模拟被证明能够与实验达成定量一致。作为系统，我们将在原子细节上实现第一个吸附PE双层的模型，我们计划从该模型中提取关于PE和层中溶剂的微观结构的有价值的信息。利用改进的CG模型，我们计划在定量水平上研究质子交换膜在界面上的结构和动力学性质，例如它们的稳定性依赖于几个参数(底物疏水性/亲水性)、水孔的分布、平行和垂直于表面的层内链和示踪粒子的迁移率以及表面粗糙度。我们还想模拟平行和垂直于层的PE拉力实验。

In the last funding period we investigated extensively the inner structure and dynamics of a small number of polyelectrolyte multilayers (PEMs) by means of atomistic and coarse-grained simulations. Our obtained results allowed us to understand some important features of PEMs, regarding the electrostatic interactions and water diffusion in particular, but also pointed out the need for a more refined coarsegrained model. Our first aim in the next funding period is to develope and test such a coarse-grained model, employing as a reference both experimental data and results from atomistic simulations which proved to be able to reach quantitative agreement with experiments. As system we will realize the first model of an adsorbed PE bilayer at atomistic detail, from which we plan to extract valuable information about the microscopic structure of the PEs and of the solvent in the layers. With the improved CG model we plan to investigate structural and dynamical properties of the PEMs in the interphase, this time at the quantitative level, such as their stability in dependence of several parameters (substrate hydrophobicity/ hydrophilicity), the distribution of water voids, the mobilities of chains and tracer particles within the layers parallel and perpendicular to the surface, and the surface roughness. We also want to simulate PE pulling experiments parallel and perpendicular to the layer.