Coarse–grained molecular modeling of the microphase structure of polyurea elastomer
Coarse–grained molecular modeling of the microphase structure of polyurea elastomer
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DOI：
10.1016/j.polymer.2019.04.039
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发表时间：
2019-08
期刊：
影响因子：
4.6
通讯作者：
Minghao Liu;J. Oswald
中科院分区：
文献类型：
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作者：
Minghao Liu;J. Oswald
我们提出了一个结构匹配的粗粒度模型的聚脲，类似于联合原子模型，其中氢原子是隐含表示。该模型使用迭代玻尔兹曼反演和一个新的精确确定的距离相关缩放函数进行训练，该函数大大减少了所需的迭代次数。由于其降低的复杂性和加速的动力学，粗粒模型可以模拟微相分离与硬域间距为5 nm，类似的聚脲弹性体的X射线散射测量。两个模型系统的形态的分析表明，一个大的，互连的硬域内的多块系统，相比，中断的硬相组成的单独的较小的带状域在一个二块系统。为了分析软段连接的拓扑结构，我们计算了它们的端到端分布，揭示了软段由大量的桥状段和少量的环状段组成。
We present a structure–matching coarse–grained model of polyurea, similar to united atom models, in which hydrogen atoms are implicitly represented. The model was trained using iteration Boltzmann inversion and a new heuristically–determined, distance–dependent scaling function that dramatically reduces the iterations required. With its reduced complexity and accelerated dynamics, the coarse–grained model can simulate microphase separation with hard domain spacing of 5 nm, comparable to x-ray scattering measurements of similar polyurea elastomers. An analysis of the morphology of two model systems shows a large, interconnected hard domain within a multiblock system, compared to an interrupted hard phase composed of separate smaller ribbon–shaped domains in a diblock system. To analyze the topology of soft segment connectivity, we calculated their end–to–end distribution, revealing that soft segments are composed of a large population of bridge–like segments and a smaller population of loop–like segments.