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arXiv 2007.11867cond-mat.softphysics.chem-ph
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polymer的自由能图谱-晶体多态性

Free-energy landscape of polymer-crystal polymorphism

Chan Liu, Jan Gerit Brandenburg, Omar Valsson, Kurt Kremer, Tristan Bereau

摘要:

多态性使加工过程如何控制材料的最终结构变得合理。到目前为止,固体中崎岖的自由能景观和极其缓慢的动力学阻碍了计算研究。我们报告的自由能景观的多晶型结晶聚合物,间规聚苯乙烯的第一次。粗粒度的metadaptics模拟使我们能够有效地采样的景观。通过量子化学计算进一步研究了两种主要多晶型物$α$和$β$之间的自由能差异。这两种方法与实验观察结果一致:它们预测$β$在标准条件下是更稳定的多晶型物。重要的是,自由能景观表明如何$α$多晶型可能导致实验观察到的动力学陷阱。多尺度建模,增强采样和量子化学计算的组合提供了一个有吸引力的策略,以揭示复杂的自由能景观与多态行为。

英文摘要:

Polymorphism rationalizes how processing can control the final structure of a material. The rugged free-energy landscape and exceedingly slow kinetics in the solid state have so far hampered computational investigations. We report for the first time the free-energy landscape of a polymorphic crystalline polymer, syndiotactic polystyrene. Coarse-grained metadynamics simulations allow us to efficiently sample the landscape at large. The free-energy difference between the two main polymorphs, $α$ and $β$, is further investigated by quantum-chemical calculations. The two methods are in line with experimental observations: they predict $β$ as the more stable polymorph at standard conditions. Critically, the free-energy landscape suggests how the $α$ polymorph may lead to experimentally observed kinetic traps. The combination of multiscale modeling, enhanced sampling, and quantum-chemical calculations offers an appealing strategy to uncover complex free-energy landscapes with polymorphic behavior.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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