超冷纳米粒子中的玻璃动态和不断增长的结构长度尺度
Weikai Qi1, Shreya Tiwary1, Richard K Bowles1,2
1Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7H 0H1, Canada.
The Journal of chemical physics
|August 22, 2025
概括
超冷纳米粒子表现出降低的玻璃过渡温度,随着尺寸的减少. 它们的放松动态与结构集群生长相关,由随机第一阶段过渡滴模型解释.
科学领域:
- 凝聚物质物理
- 材料科学
- 计算化学
背景情况:
- 超冷液体在玻璃过渡附近表现出复杂的动态.
- 与散装材料相比,纳米粒子系统具有独特的热力学和动态性质.
- 了解结构动力学关系对于设计具有特定性质的材料至关重要.
研究的目的:
- 研究超冷二元纳米粒子结构与动态之间的关系.
- 确定颗粒大小如何影响玻璃过渡温度和放松行为.
- 探索理论模型对纳米粒子动力学的适用性.
主要方法:
- 分子动力学模拟用于模拟二进制的莱纳德-斯纳米粒子.
- 模拟了不同的颗粒大小,以观察大小依赖的效应.
- 分析包括计算玻璃过渡温度,放松时间 (中间散射函数) 和局部结构.
主要成果:
- 纳米颗粒的玻璃过渡温度与散装相比显著降低,随着N-1/3与颗粒大小的减少的关系.
- 在低温下放松时间的增长与物理集群的形成相结合.
- 观察到的行为与随机第一阶段过渡滴模型相一致,具有尺寸依赖的指数.
结论:
- 纳米粒子大小在改变超冷系统的玻璃转换和动态方面发挥着关键作用.
- 随机第一阶段过渡滴模型为理解纳米粒子动态提供了一个有用的框架,尽管需要依赖大小的修改.
- 这项研究提供了纳米级超冷液体的基本物理知识.
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