在快速火过程中单聚乙烯链折叠的分子动力学模拟,使用全原子和联合原子模型
Jingfu Shi1, Jianqiu Zhou2, Lei Liu1
1National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150001, P. R. China. miaocq@hit.edu.cn.
Physical chemistry chemical physics : PCCP
|September 20, 2024
概括
分子动力学模拟显示了聚乙烯链的折叠行为. 特定的力场在快速火过程中促进有序结构,而另一些则导致无形状态.
科学领域:
- 聚合物科学 聚合物科学
- 计算化学是一种计算化学.
- 材料科学是一种材料科学.
背景情况:
- 了解聚合物链折叠对于预测材料特性至关重要.
- 分子动力学模拟为纳米尺度的结构变化提供了洞察力.
研究的目的:
- 为了研究在快速火条件下单个聚乙烯链的折叠行为.
- 分析不同力场对链形状和结晶的影响.
主要方法:
- 使用全原子和联合原子模型的分子动力学模拟.
- 分析链形状,折叠结构,自由能量和结晶.
- 模拟100 K ns-1的快速火和500 K的同热放松.
主要成果:
- 在同热放松过程中观察到一个两阶段的链崩机制 (局部到全球) 进入化球体状态.
- 在快速火下,AMBER-AA和OPLS-AA力场在全原子模型中诱导了有序结构.
- 联合原子模型在快速火过程中显示了最小的结构变化.
- 珀-AA和OPLS-AA力场导致了更高的结晶度和有序的板状结构.
结论:
- 选择的力场显著影响聚乙烯链折叠和结晶在快速火下.
- 具有AMBER-AA或OPLS-AA力场的全原子模型在模拟聚乙烯中有序结构形成方面是有效的.
- 在快速冷却过程中,聚乙烯链在其他测试的力场下保持无形.
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