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.

中文翻译：

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聚环氧乙烷的可转移MARTINI模型

由于以前的聚环氧乙烷（PEO）的MARTINI模型的缺陷，我们提出了一种具有高度可转移性的新模型。该模型的参数化基于（a）从水到极性不同的溶剂转移二甲氧基乙烷（PEO二聚体）的8组自由能；（b）高稀释度的水中的回转半径；（c）原子模拟的匹配角和二面角分布。我们证明了我们的模型在五个不同的应用领域中表现良好：（1）它可产生准确的密度和相态或小的PEO低聚物和水混合物；（2）在三种不同的溶剂（水，二甘醇二甲醚和苯）中，在较宽的分子量范围内（〜1.2 kg / mol至21 kg / mol），其链的尺寸与实验结果吻合良好；（3）定性地再现了在刷子和蘑菇状态下含有PEG化脂质的脂质双层的结构特征；（4）能够再现几种PEO基非离子表面活性剂在水中的相行为；（5）可以与现有的MARTINI PS结合使用，以模拟PS-PEO嵌段共聚物。总体而言，新的PEO模型优于以前的模型，并且具有高度的可移植性。