膜科学与技术

基于结构柔韧性的MOFs材料分子模拟力场研究

作者：徐春华，王秀民

单位： 1中国石油大学（华东）机电工程学院，山东青岛 266580 2中国石油大学（华东）材料科学与工程学院，山东青岛 266580

关键词：金属-有机框架材料；柔韧性；动力学模拟；力场；孔径

出版年,卷(期):页码： 2022,42(1):98-103

摘要：

金属-有机框架材料（Metal-Organic Frameworks, MOFs）结构柔韧性的分子模拟研究对于准确预测实验结果具有重要的指导意义。因此采用分子动力学模拟的方法研究了三种不同力场（Dreiding、UFF和UFF4MOF力场）下的不同电荷状态（无电荷、Qeq电荷和DDEC电荷）对沸石咪唑酯骨架结构材料（Zeolitic Imidazolate Frameworks，ZIFs）柔韧性的影响，通过筛选精确的柔性力场，探究了力场对金属-有机框架材料孔径分布的影响。结果表明，在考虑ZIF-8最大自由球直径df的情况下，UFF力场下DDEC电荷分布模型精确度最高；在考虑ZIF-8最大包容球直径dif的情况下，UFF力场的无电荷分布模型精确度最高。该结果为进一步研究ZIF-8的膜分离性能提供了更准确的力场，用于预测材料性能。关于两者的精确程度差异和对Zn周围的键长和键角施加限制对不同力场模型的影响规律将在后续研究中进行探讨。

The molecular simulation study on the structural flexibility of metal organic framework materials (MOFs) has important guiding significance for the accurate prediction of experimental results. Molecular dynamics simulation methods are used to study the effects of different charge states (No charge, Qeq charge and DDEC charge) under three different force fields (Dreiding、UFF and UFF4MOF force field) on the flexibility of zeolite imidazolate framework materials (ZIFs). And by screening the precise flexible force field, the influence of the force field on the aperture distribution of the metal organic frame material is explored. The results show that the accuracy of DDEC charge distribution model under UFF force field is the highest considering the maximum free sphere diameter df of ZIF-8. Considering the maximum diameter dif of ZIF-8, the charge-free distribution model of UFF force field has the highest accuracy. The results provide a more accurate force field for further study on the membrane separation performance of ZIF-8, which can be used to predict the material properties. The difference in accuracy between them and the influence of restrictions on bond length and bond angle around Zn on different force field models will be discussed in the follow-up study.

徐春华（1967-），女，江苏宜兴人，高级实验师，主要研究方向：计算机应用

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