Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA.
J Chem Phys. 2018 Jul 14;149(2):024902. doi: 10.1063/1.5031789.
Nonequilibrium molecular dynamics simulations are used to investigate the influence of hydrodynamic interactions on vertical segregation (stratification) in drying mixtures of long and short polymer chains. In agreement with previous computer simulations and theoretical modeling, the short polymers stratify above the long polymers at the top of the drying film when hydrodynamic interactions between polymers are neglected. However, no stratification occurs under the same drying conditions when hydrodynamic interactions are incorporated through an explicit solvent model. Our analysis demonstrates that models lacking hydrodynamic interactions do not faithfully represent stratification in drying mixtures, in agreement with the recent analysis of an idealized model for diffusiophoresis. Hydrodynamic interactions must be incorporated into such models for drying mixtures in future.
采用非平衡分子动力学模拟研究了流体力学相互作用对长链和短链聚合物混合物在干燥过程中垂直分离（分层）的影响。与以前的计算机模拟和理论模型一致，当忽略聚合物之间的流体力学相互作用时，短聚合物在干燥膜顶部优先于长聚合物分层。然而，当通过显式溶剂模型纳入流体力学相互作用时，在相同的干燥条件下不会发生分层。我们的分析表明，缺乏流体力学相互作用的模型不能真实地代表干燥混合物中的分层，这与最近对扩散泳理想化模型的分析一致。在未来，此类干燥混合物模型必须纳入流体力学相互作用。
