Bichler Karin J, Jakobi Bruno, Sakai Victoria García, Klapproth Alice, Mole Richard A, Schneider Gerald J
Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Nano Lett. 2021 May 26;21(10):4494-4499. doi: 10.1021/acs.nanolett.1c01379. Epub 2021 May 14.
The understanding of materials requires access to the dynamics over many orders of magnitude in time; however, single analytical techniques are restricted in their respective time ranges. Assuming a functional relationship between time and temperature is one viable tool to overcome these limits. Despite its frequent usage, a breakdown of this assertion at the glass-transition temperature is common. Here, we take advantage of time- and length-scale information in neutron spectroscopy to show that the separation of different processes is the minimum requirement toward a more universal picture at, and even below, the glass transition for our systems. This is illustrated by constructing the full proton mean-square displacement for three bottlebrush polymers from femto- to nanoseconds, with simultaneous information on the partial contributions from segmental relaxation, methyl group rotation, and vibrations. The information can be used for a better analysis of results from numerous techniques and samples, improving the overall understanding of materials properties.
对材料的理解需要获取跨越多个数量级时间的动力学信息；然而，单一的分析技术在其各自的时间范围内受到限制。假设时间和温度之间存在函数关系是克服这些限制的一种可行方法。尽管这种假设经常被使用，但在玻璃化转变温度下这种假设失效是很常见的。在这里，我们利用中子光谱中的时间和长度尺度信息表明，对于我们的体系，分离不同过程是在玻璃化转变温度及以下获得更通用图像的最低要求。通过构建三种刷状聚合物从飞秒到纳秒的完整质子均方位移，并同时获得关于链段弛豫、甲基旋转和振动的部分贡献的信息，这一点得到了说明。这些信息可用于更好地分析来自众多技术和样品的结果，从而提高对材料性能的整体理解。
