Coarse-Grained Potentials of Poly(vinyl alcohol)/Graphene Oxide Interfaces

Graphene oxide (GO)-based polymer
composites have attracted more
and more interest due to their excellent mechanical and physical properties,
in which the dispersion and content of GO dominate these properties.
However, it is an enormous challenge to exactly understand interfacial
interactions between GO and polymers and obtain their properties using
all-atom (AA) molecular dynamics (MD) simulations owing to the huge
computational cost. In this study, we construct the coarse-grained
(CG) potentials of poly­(vinyl alcohol) (PVA) melts and GO as well
as PVA/GO interfaces based on hybrid iterative Boltzmann inversion
and force matching methods. The established CG potentials are further
validated by the density distribution and wetting behaviors of PVA
melts on the GO surface, which are of great help toward describing
the thermodynamic properties of GO-based PVA composites. The present
CG models improve the computational efficiency by an order of magnitude,
and the CG framework is also transferrable to other interfacial systems.

基于氧化石墨烯（Graphene oxide，GO）的聚合物复合材料因其优异的力学与物理性能而受到日益广泛的关注，其中氧化石墨烯的分散状态与含量对这些性能起到主导作用。然而，由于计算成本高昂，通过全原子（all-atom，AA）分子动力学（molecular dynamics，MD）模拟精准解析氧化石墨烯与聚合物之间的界面相互作用并获取其相关性能，仍是一项极具挑战性的难题。本研究基于混合迭代玻尔兹曼反演与力匹配方法，构建了聚乙烯醇（poly(vinyl alcohol)，PVA）熔体、氧化石墨烯以及聚乙烯醇/氧化石墨烯界面的粗粒化（coarse-grained，CG）势函数。所构建的粗粒化势函数通过聚乙烯醇熔体在氧化石墨烯表面的密度分布与润湿行为得到了进一步验证，这对精准描述基于氧化石墨烯的聚乙烯醇复合材料的热力学性能具有重要意义。本研究提出的粗粒化模型将计算效率提升了一个数量级，且该粗粒化框架同样可推广至其他界面体系。