Broadband-dielectric-spectroscopy study of molecular dynamics in a mixture of itraconazole and glycerol in glassy, smectic-A, and isotropic phases,Physical Review E

当前位置： X-MOL 学术 › Phys. Rev. E › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Broadband-dielectric-spectroscopy study of molecular dynamics in a mixture of itraconazole and glycerol in glassy, smectic-A, and isotropic phases
Physical Review E ( IF 2.2 ) Pub Date : 2021-09-09 , DOI: 10.1103/physreve.104.034702
M Rams-Baron _{1,

2} , D Kramarczyk _{1,

2} , J Knapik-Kowalczuk _{1,

2} , B Hachula ₃ , A Kocot ₄ , M Paluch _{1,

2}

Affiliation

Itraconazole (ITZ) is a thermotropic liquid crystal that exhibits isotropic, nematic, and smectic phases on cooling towards the glass transition upon melting. Over the years, new aspects regarding the liquid-crystalline ordering of this antifungal drug were systematically revealed. It has been shown recently that the temperature range of individual mesophases in ITZ can be modified by adding a small amount of glycerol (GLY). Moreover, above the critical concentration of 5% w/w, a smectic to nematic transition can be avoided. Here we go one step further, and we used broadband dielectric spectroscopy to investigate the new phase behavior of the ITZ-GLY mixture (5% w/w). To confirm the phase transformations of the ITZ-GLY mixture, differential scanning calorimetry was also employed. The analysis of molecular dynamics of the ITZ-GLY mixture in the glassy and isotropic phases revealed features similar to those observed for neat ITZ. Two relaxation processes were identified in the smectic-A phase, with similar temperature dependence, most likely related to the fast rotations around the long axis of a molecule. Additionally, the derivative analysis revealed another low-frequency process hidden under DC conductivity ascribed to the slow rotations about a short axis. We will show that the differences in the molecular organization in the smectic-A and isotropic phases leave a clear fingerprint on the temperature behavior of relaxation times and other dielectric parameters, such as DC conductivity and dielectric strength, for which a pretransition effect has been detected.

中文翻译：

玻璃态、近晶 A 和各向同性相中伊曲康唑和甘油混合物中分子动力学的宽带介电光谱研究

伊曲康唑 (ITZ) 是一种热致液晶，在熔化后冷却至玻璃化转变时呈现各向同性、向列和近晶相。多年来，系统地揭示了有关这种抗真菌药物的液晶排序的新方面。最近已经表明，可以通过添加少量甘油 (GLY) 来修改 ITZ 中各个中间相的温度范围。此外，高于 5% w/w 的临界浓度，可以避免近晶向向列转变。在这里，我们更进一步，我们使用宽带介电光谱来研究 ITZ-GLY 混合物 (5% w/w) 的新相行为。为了确认 ITZ-GLY 混合物的相变，还采用了差示扫描量热法。玻璃态和各向同性相中 ITZ-GLY 混合物的分子动力学分析揭示了与纯 ITZ 观察到的特征相似的特征。在近晶中发现了两个弛豫过程-具有相似温度依赖性的相，最有可能与围绕分子长轴的快速旋转有关。此外，导数分析揭示了隐藏在直流电导率下的另一个低频过程，这归因于绕短轴的缓慢旋转。我们将证明近晶-A和各向同性相中分子组织的差异在弛豫时间和其他介电参数（例如直流电导率和介电强度）的温度行为上留下了清晰的指纹，已检测到预跃迁效应.

更新日期：2021-09-10

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11