Cao Dapeng, Zhu Menghan, Wang Wenchuan
Lab of Molecular and Materials Simulation, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, P R China.
J Phys Chem B. 2006 Nov 2;110(43):21882-9. doi: 10.1021/jp064040m.
We use a hybrid density functional approach to investigate the microstructure and self-assembly of inhomogeneous rigid rodlike chains between two neutral surfaces, i.e., two hard walls. In the calculation, the rodlike molecule is modeled as a rigid rod linearly connected by the tangent sphere beads. The hybrid method combines a single-chain Monte Carlo (MC) simulation for the ideal-gas part of Helmholtz energy and a DFT approach for the excess Helmholtz energy. The DFT approach includes a modified fundamental measure theory for the excluded-volume effect, the first order thermodynamics perturbation theory for chain connectivity, and the mean field approximation for the van der Waals attraction. We investigate the effect of the chain length (i.e., aspect ratio) of the rodlike molecule and the separation between two surfaces on the microstructure and self-assembly of inhomogeneous rigid rodlike chains. For the athermal systems, the rodlike chain fluids present a smaller partitioning coefficient compared to the flexible chain fluids. For the thermal systems, lamellar thin films formed by the rigid rodlike molecules perpendicular to the neutral surface are observed. The effects of the head-head interaction and the separation on the self-assembly of the rodlike chain fluids in the slit are investigated.
我们采用混合密度泛函方法来研究两个中性表面（即两个硬壁）之间非均匀刚性棒状链的微观结构和自组装。在计算中，棒状分子被建模为通过切向球珠线性连接的刚性棒。该混合方法将亥姆霍兹自由能的理想气体部分的单链蒙特卡罗（MC）模拟与过量亥姆霍兹自由能的密度泛函理论（DFT）方法相结合。DFT方法包括用于排除体积效应的修正基本度量理论、用于链连接性的一阶热力学微扰理论以及用于范德华引力的平均场近似。我们研究了棒状分子的链长（即长径比）和两个表面之间的间距对非均匀刚性棒状链的微观结构和自组装的影响。对于无热系统，与柔性链流体相比，棒状链流体呈现出较小的分配系数。对于热系统，观察到由垂直于中性表面的刚性棒状分子形成的层状薄膜。研究了头对头相互作用和间距对狭缝中棒状链流体自组装的影响。
