1,6-脱水-β-D-甘露吡喃糖（塑料晶体）和2,3,4-三-O-乙酰基-1,6-脱水-β-D-吡喃葡萄糖（规范玻璃）的高压介电研究,The Journal of Chemical Physics

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1,6-脱水-β-D-甘露吡喃糖（塑料晶体）和2,3,4-三-O-乙酰基-1,6-脱水-β-D-吡喃葡萄糖（规范玻璃）的高压介电研究
The Journal of Chemical Physics ( IF 3.1 ) Pub Date : 2018-05-29 , DOI: 10.1063/1.5032209
Dawid Heczko ₁ , Ewa Kamińska ₁ , Aldona Minecka ₁ , Andrzej Dzienia _{2,

3} , Karolina Jurkiewicz _{3,

4} , Magdalena Tarnacka _{3,

4} , Agnieszka Talik _{3,

4} , Kamil Kamiński _{3,

4} , Marian Paluch _{3,

4}

Affiliation

宽带介电谱法用于研究两种无水多糖的分子动力学，即1,6-脱水-β-D-甘露吡喃糖，anhMAN（氢键体系）和2,3,4-三-O-乙酰基-1,6 -anhydro-β-D-吡喃葡萄糖，ac-anhGLU（范德华材料），在不同的热力学条件下。此外，将报告的数据与最近发布的其他两个氢键系统即1,6-脱水-β-D-吡喃葡萄糖（anhGLU）和D-葡萄糖（D-GLU）的数据进行了比较。通过直接比较具有相似化学结构但在自由度，复杂度和分子间相互作用方面存在显着差异的材料的动力学行为，可以探究压缩对材料脆性，温度-压力叠加和压力系数的影响。玻璃态晶体/玻璃化转变温度（

d Ť_{G C} / d p

;

d Ť_{G} / d p

）。而且，两者之间的相关性

d Ť_{G C} / d p

由高压介电数据通过实验确定，并且首次针对塑料晶体（anhGLU和anhMAN）测试了Ehrenfest方程。有趣的是，两种方法之间都找到了令人满意的协议。这是一个非常有趣的发现，可以通过以下事实加以合理化：所研究的材料具有较低的复杂性（相对于分子迁移率而言较低的自由度）以及有序的内部结构。因此，可以推测出，与普通玻璃相比，可通过使用单阶参数来描述塑料晶体的动力学。但是，为了进一步证实这一论点，需要进行压力体积温度（PVT）实验，以计算出普利戈金衰变比。

"点击查看英文标题和摘要"

High-pressure dielectric studies on 1,6-anhydro-β-D-mannopyranose (plastic crystal) and 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-glucopyranose (canonical glass)

Broadband Dielectric Spectroscopy was applied to investigate molecular dynamics of two anhydrosaccharides, i.e., 1,6-anhydro-β-D-mannopyranose, anhMAN (hydrogen-bonded system) and 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-glucopyranose, ac-anhGLU (van der Waals material), at different thermodynamic conditions. Moreover, the reported data were compared with those recently published for two other H-bonded systems, i.e., 1,6-anhydro-β-D-glucopyranose (anhGLU) and D-glucose (D-GLU). A direct comparison of the dynamical behavior of the materials with a similar chemical structure but significantly differing by the degrees of freedom, complexity, and intermolecular interactions made it possible to probe the impact of compression on the fragility, Temperature-Pressure Superpositioning and pressure coefficient of the glassy crystal/glass transition temperatures (

d T_{g c} / d p

;

d T_{g} / d p

). Moreover, the correlation between

d T_{g c} / d p

determined experimentally from the high-pressure dielectric data and the Ehrenfest equation has been tested for the plastic crystals (anhGLU and anhMAN) for the first time. Interestingly, a satisfactory agreement was found between both approaches. It is a quite intriguing finding which can be rationalized by the fact that the studied materials are characterized by the low complexity (lower degrees of freedom with respect to the molecular mobility) as well as ordered internal structure. Therefore, one can speculate that in contrast to the ordinary glasses the dynamics of the plastic crystals might be described with the use of a single order parameter. However, to confirm this thesis further, pressure-volume-temperature (PVT) experiments enabling calculations of the Prigogine Defay ratio are required.

更新日期：2018-06-01

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