Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
J Chem Phys. 2010 Feb 14;132(6):064903. doi: 10.1063/1.3314730.
The formation of interface from an initial sharp interface in polydisperse A/B blends is studied using the external potential dynamic method. The present model is a nonlocal coupling model as we take into account the correlation between segments in a single chain. The correlation is approximately expressed by Debye function and the diffusion dynamics are based on the Rouse chain model. The chain length distribution is described by the continuous Schulz distribution. Our numerical calculation indicates that for a wide range of the Flory-Huggins parameter the broadening of interface with respect to time obeys a power law at early time, and the power indices are the same for both monodisperse and polydisperse blends. The power index is larger than that in the local coupling model. However, there is no unified scaling form of the broadening of the interface width if only the interfacial width at equilibrium is taken into account as the characteristic length of the system, because the correlation makes an extra characteristic length in the system, and the polydispersity is related to this length.
使用外部位势动力学方法研究了多分散 A/B 共混物中初始尖锐界面的界面形成。本模型是一种非局部耦合模型，因为我们考虑了单链中链段之间的相关性。相关性通过德拜函数近似表示，扩散动力学基于罗瑟链模型。链长分布由连续舒尔茨分布描述。我们的数值计算表明，对于广泛的弗洛里-哈金斯参数，界面随时间的展宽在早期遵循幂律关系，单分散和多分散共混物的幂指数相同。幂指数大于局部耦合模型的幂指数。然而，如果仅将平衡时的界面宽度作为系统的特征长度，则界面宽度的展宽没有统一的标度形式，因为相关性在系统中增加了一个特征长度，而多分散性与这个长度有关。
