在分子眼镜中超越α放松的物理衰老
Valerio Di Lisio1, Vasiliki-Maria Stavropoulou2, Daniele Cangialosi1,2
1Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain.
The Journal of chemical physics
|August 8, 2023
概括
眼镜的物理衰老涉及超出初级α放松的分子机制,特别是在较低的温度下. 这项研究揭示了比单独通过α放松预测的更快的平衡,表明复杂的动态.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 物理衰老描述了玻璃热力学状态缓慢接近平衡的过程.
- 这一过程通常仅归因于主要的α放松.
- 了解老化动力学对于预测玻璃随时间推移的行为至关重要.
研究的目的:
- 在广泛的温度范围内研究小分子中物理衰老的动力学.
- 挑战单独的α放松控制玻璃老化的假设.
- 探索促进玻璃平衡的替代分子机制.
主要方法:
- 利用快速扫描热量计来监测不同衰老时间内的体状态演变.
- 采用一种独立于模型的方法,专注于达到平衡的时间.
- 应用了经过修改的单参数衰老模型,其中包含了对非线性衰老效应的密度缩放.
主要成果:
- 阿尔法放松足够地描述了在玻璃过渡温度附近的衰老,以及在较低温度下平衡的最后阶段.
- 在较低的老化温度下,玻璃热力学演变的重要部分发生的速度远远快于单独通过α放松来预测的速度.
- 该研究观察到仅基于α放松的预测的偏差,特别是在延长的老化时间和较低的温度下.
结论:
- 阿尔法放松不足以完全描述所有老化条件下的玻璃平衡.
- 除了α放松之外,还需要额外的分子机制来解释观察到的物理衰老动力学.
- 玻璃平衡涉及复杂的动态,受多个分子过程的影响,特别是在较低的温度和较长的老化时间.
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