论文标题
干燥液滴中聚合物混合物的分层：流体动力学和扩散
Stratification of polymer mixtures in drying droplets: hydrodynamics and diffusion
论文作者
论文摘要
我们使用分子模拟研究了干燥液滴中短和长聚合物链的混合物的蒸发诱导的分层。我们通过比较通过多颗粒碰撞动力学技术与自由流血的Langevin Dynamics模拟进行比较，我们系统地研究了流体动力相互作用（HI）对此过程的影响。我们发现，当包括HI时，干燥的上膜形态是均匀的，但在忽略HI时被分层在核心壳结构中（较短的聚合物形成壳）。模拟方法明确将这种差异归因于两个模型中溶剂的处理。我们通过测量聚合物混合物的现象学多组分扩散系数来合理化分层的存在（或不存在）。扩散系数不仅表明了溶剂回流的重要性，而且在聚合物之间在控制干燥的上膜形态学方面也很重要。
We study the evaporation-induced stratification of a mixture of short and long polymer chains in a drying droplet using molecular simulations. We systematically investigate the effects of hydrodynamic interactions (HI) on this process by comparing hybrid simulations accounting for HI between polymers through the multiparticle collision dynamics technique with free-draining Langevin dynamics simulations neglecting the same. We find that the dried supraparticle morphologies are homogeneous when HI are included but are stratified in core--shell structures (with the short polymers forming the shell) when HI are neglected. The simulation methodology unambiguously attributes this difference to the treatment of the solvent in the two models. We rationalize the presence (or absence) of stratification by measuring phenomenological multicomponent diffusion coefficients for the polymer mixtures. The diffusion coefficients show the importance of not only solvent backflow but also HI between polymers in controlling the dried supraparticle morphology.
