Grunewald Fabian, Rossi Giulia, de Vries Alex H, Marrink Siewert J, Monticelli Luca
Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Groningen , The Netherlands.
Physics Department , University of Genoa , via Dodecaneso 33 , 16146 Genoa , Italy.
J Phys Chem B. 2018 Jul 26;122(29):7436-7449. doi: 10.1021/acs.jpcb.8b04760. Epub 2018 Jul 13.
Motivated by the deficiencies of the previous MARTINI models of poly(ethylene oxide) (PEO), we present a new model featuring a high degree of transferability. The model is parametrized on (a) a set of 8 free energies of transfer of dimethoxyethane (PEO dimer) from water to solvents of varying polarity; (b) the radius of gyration in water at high dilution; and (c) matching angle and dihedral distributions from atomistic simulations. We demonstrate that our model behaves well in five different areas of application: (1) it produces accurate densities and phase behavior or small PEO oligomers and water mixtures; (2) it yields chain dimensions in good agreement with the experiment in three different solvents (water, diglyme, and benzene) over a broad range of molecular weights (∼1.2 kg/mol to 21 kg/mol); (3) it reproduces qualitatively the structural features of lipid bilayers containing PEGylated lipids in the brush and mushroom regime; (4) it is able to reproduce the phase behavior of several PEO-based nonionic surfactants in water; and (5) it can be combined with the existing MARTINI PS to model PS-PEO block copolymers. Overall, the new PEO model outperforms previous models and features a high degree of transferability.
受先前聚环氧乙烷（PEO）的MARTINI模型缺陷的启发，我们提出了一种具有高度转移性的新模型。该模型基于以下参数进行参数化：（a）一组8个二甲氧基乙烷（PEO二聚体）从水转移到不同极性溶剂中的转移自由能；（b）高稀释度下在水中的回转半径；（c）来自原子模拟的匹配角和二面角分布。我们证明我们的模型在五个不同的应用领域表现良好：（1）它能准确预测小PEO低聚物和水混合物的密度和相行为；（2）在广泛的分子量范围（约1.2 kg/mol至21 kg/mol）内，它所产生的链尺寸与在三种不同溶剂（水、二甘醇二甲醚和苯）中的实验结果高度吻合；（3）它能定性地再现刷状和蘑菇状区域中含聚乙二醇化脂质的脂质双层的结构特征；（4）它能够再现几种基于PEO的非离子表面活性剂在水中的相行为；（5）它可以与现有的MARTINI PS相结合，用于模拟PS-PEO嵌段共聚物。总体而言，新的PEO模型优于先前的模型，并具有高度的转移性。
