玻璃形成液体的快速与缓慢的物理衰老
Ranko Richert1, Jan P Gabriel2
1School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, USA.
The Journal of chemical physics
|August 28, 2023
概括
电场使得物理衰老的研究速度更快. 这项研究比较了乙烯基碳酸乙烯的现场诱导的结构恢复与温度诱导的老化,发现恢复比平衡放松更慢.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 聚合物科学 聚合物科学
背景情况:
- 物理衰老是一个关键的现象,会随着时间的推移影响材料的特性.
- 与传统的温度跳跃方法相比,电场诱导的衰老可以实现更快的实验测量.
- 对比现场诱导和温度诱导的衰老动态对于全面了解结构恢复至关重要.
研究的目的:
- 研究和比较不同时间尺度的乙烯基碳酸乙烯 (VEC) 现场诱导的结构恢复的动态.
- 建立由电场启动的结构恢复和通过介电谱学确定的平衡结构放松之间的关系.
- 要确定恢复和放松动态之间的关系是否依赖于温度.
主要方法:
- 在两种不同的时间尺度上对VEC进行了现场诱导的结构恢复测量:在181K时1.0毫秒,在169K时33秒.
- 介电松测量用于确定在线性响应极限中的平衡结构松动力学.
- 为了进行比较分析,选择了实验条件,以跨越时间尺度 (4.5 十年) 的显著差异.
主要成果:
- 结构恢复的速度是平衡结构放松的约两倍.
- 观察到结构恢复和放松动态之间的关系在测试温度范围内是不变的.
- 数据为比较现场诱导的衰老与较慢的温度诱导的衰老过程提供了一个桥梁.
结论:
- 现场诱导的衰老为研究在实验上可访问的时间尺度上的缓慢动态提供了有价值的方法.
- 观察到的温度不变性表明恢复和放松机制之间存在着根本的联系.
- 这项研究促进了对像VEC这样的材料物理衰老的理解,这对材料的稳定性和性能有影响.
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