分子动力学和近T现象周期性Thioethers的现象
Hubert Hellwig1, Andrzej Nowok2, Paulina Peksa2
1Center for Integrated Technology and Organic Synthesis (CiTOS), MolSys Research Unit, University of Liège, B6a, Room 3/19, Allée du Six Août 13, 4000 Liege, Belgium.
International journal of molecular sciences
|December 23, 2023
概括
合成和研究了新的循环硫乙烯,显示了高的玻璃过渡温度和多个介电松过程. 它们的特性是普通和大型分子玻璃制造物的桥梁,在材料科学中具有潜在的应用.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 超分子化学 超分子化学
背景情况:
- 冠状玻璃形成器是一种具有高玻璃过渡温度的有限材料类.
- 循环乙烯代表了开发新玻璃成型材料的未经探索的领域.
- 了解分子动力学和放松过程对于材料性质预测至关重要.
研究的目的:
- 合成和描述具有潜在玻璃形成性能的新型循环硫乙烯.
- 研究这些化合物的分子动力学和介电松行为.
- 探索分子结构,摩尔质量和玻璃过渡温度之间的关系.
主要方法:
- 三种新型循环乙烯基乙烯的合成:2,3-(4'-甲基) -1,4,7,10-四甲基二烯,2,3,14,15-bis(4',4′′(5′′) -甲基) -1,4,7,10,13,16,19,22,25-octathiacyclotetracosa-2,14-diene,以及2,3,8,9-bis(4',4′′(5′′) -甲基) -1,4,7,10-tetrathiacyclododeca-2,8-diene.
- 模拟分子动力学以研究结构性和动态性质.
- 介电光谱分析放松过程和玻璃过渡温度 (T).
- 对化合物1进行高压研究,以确定其压力-温度行为.
主要成果:
- 合成的循环硫乙烯表现出高的玻璃过渡温度 (254283 K),将它们归类为冠状玻璃形成物.
- 玻璃过渡温度 (T) 遵循与摩尔质量的亚线性功率定律.
- 观察到多个介电松过程,包括主要的结构松 (Johari-Goldstein过程) 和分子内二次松.
- 化合物1显示了压力诱导的T的增加,其系数为197 ± 8K/GPa.
结论:
- 新型循环硫乙烯可以作为普通和大型的分子玻璃形成剂,具有独特的物理性质.
- 观察到的介电松机制为这些材料的分子动力学提供了洞察力.
- 这些发现有助于理解循环乙烯基玻璃制造器中的结构性质关系.
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