Rams-Baron M, Jedrzejowska A, Jurkiewicz K, Matussek M, Ngai K L, Paluch M
August Chełkowski Institute of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland.
Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland.
J Phys Chem Lett. 2021 Jan 14;12(1):245-249. doi: 10.1021/acs.jpclett.0c03377. Epub 2020 Dec 17.
In this Letter we report significant differences in the dielectric behavior of four nonpolymeric and sizable glass-forming molecules with related chemical structures. They belong to the recently constituted class of sizable glass-formers [Jedrzejowska et al. 2020, 101, 010603], for which the pattern of change in dielectric properties with structure has not yet been fully discovered. In the present study we tackle the fundamental problem of the structure-dynamics relationship. It was made possible by judicious choice of investigated systems with the values of dipole moments purposely kept at about the same level, and the only difference is the structure of the terminal substituents applied. The remarkable effect revealed by broadband dielectric spectroscopy is a large difference in the frequency dispersion of the α-relaxation for the systems studied. This interesting finding can be rationalized by the results of X-ray diffraction, clearly indicating the dissimilarities in the local intermolecular structure.
在本信函中，我们报告了四种具有相关化学结构的非聚合且尺寸可观的玻璃形成分子在介电行为上的显著差异。它们属于最近构成的尺寸可观的玻璃形成剂类别[Jedrzejowska等人，2020，101，010603]，对于这类物质，介电性质随结构变化的模式尚未被完全发现。在本研究中，我们解决结构 - 动力学关系这一基本问题。通过明智地选择所研究的体系得以实现，这些体系的偶极矩值特意保持在大致相同的水平，唯一的差异在于所应用的末端取代基的结构。宽带介电谱揭示的显著效应是所研究体系的α弛豫在频率色散上存在很大差异。这一有趣的发现可以通过X射线衍射结果得到合理解释，该结果清楚地表明了局部分子间结构的差异。
