从一个联合介电松和光学克尔效应研究的伊米达离子液体的动力学:证据介电镜聚合的证据
David A Turton1, Johannes Hunger, Alexander Stoppa
1Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, UK. david.turton@phys.strath.ac.uk
Journal of the American Chemical Society
|July 15, 2009
概括
室温离子液体表现出复杂的分子间动力学. 这些液体中新发现的一种低频放松解释了它们异常高的粘度,与新出现的中介层结构有关.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 频谱学是一种光谱学.
背景情况:
- 室温离子液体 (RTILs) 是在环境温度下是液态的盐,在各种领域都有应用.
- 了解RTILs的分子间动态对于优化其性能至关重要.
- 之前的研究在特拉赫兹区域中表征复杂的动态方面面临着挑战.
研究的目的:
- 为了研究基于1,3-dialkylimidazolium的RTILs的分子间动力学 ([emim][BF(4),[emim][DCA]和[bmim][DCA]).
- 分析太赫兹光谱区域,通常以重叠模式为特征.
- 阐明这些RTIL中异常高粘度的起源.
主要方法:
- 使用了超快的光学克尔效应 (OKE) 光谱.
- 使用过电放松光谱 (DRS).
- 用时域特拉赫兹和远红外FTIR光谱进行增强测量.
主要成果:
- 从1 GHz以下到10 THz,测量了分子间动力学.
- 观察到一种强烈的低频 (亚α) 放松.
- 将这种放松与在模拟中识别的中视层结构 (聚合物/集群) 相关联.
结论:
- 亚α放松是控制RTIL动态的一个关键特征.
- 中层结构形成解释了这些RTILs的高粘度.
- 光谱技术的组合提供了对RTIL动态的全面理解.
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