Dynamics and ionic conductivity of ionic liquid crystals forming a hexagonal columnar mesophase.
Dynamics and ionic conductivity of ionic liquid crystals forming a hexagonal columnar mesophase.
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形成六方柱状中间相的离子液晶的动力学和离子电导率
DOI：
10.1039/c7cp08186c
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Schönhals
中科院分区：
文献类型：
--
作者：
A. Yildirim;P. Szymoniak;K. Sentker;M. Butschies;A. Bühlmeyer;P. Huber;S. Laschat;A. Schönhals
首次采用宽带介电谱（BDS）和比热谱（SHS）相结合的方法研究了两种具有不同烷基链长度的线型四甲基三氟甲磺酸胍离子液晶（ILC）的分子迁移率.通过自组装，这些离子液体可以形成一个六方有序的中间相除了塑性结晶相和各向同性状态。三个介电活性过程中发现，使用BDS的两个样品。在低温下，观察到塑性结晶状态下的γ-过程，这归因于胍头中包括氮原子在内的甲基的局部波动。在较高的温度下，但仍处于塑性结晶状态，发生α1过程。利用SHS检测到α2-过程，但弛豫时间与α1-弛豫时间的温度依赖性完全不同。这一结果进行了详细讨论，并提出了不同的分子分配的过程。在更高的温度下，电导率的测定结果表明，在从塑性结晶相到六方柱状相的相变过程中，直流电导率增加了4个数量级，这一结果可追溯到堆积芳族体系中离域电子跳跃引起的电荷传输机制的变化（塑性相）转变为在ILC六方中间相中沿沿着超分子柱形成的准一维离子通道中以离子导电为主的离子通道。
For the first time, the molecular mobility of two linear-shaped tetramethylated guanidinium triflate ionic liquid crystals (ILCs) having different lengths of alkyl chains was investigated using a combination of broadband dielectric spectroscopy (BDS) and specific heat spectroscopy (SHS). By self-assembly, these ILCs can form a hexagonal ordered mesophase besides plastic crystalline phases and the isotropic state. Three dielectric active processes were found using BDS for both samples. At low temperatures, a γ-process in the plastic crystalline state is observed which is assigned to localized fluctuations of methyl groups including nitrogen atoms in the guanidinium head. At higher temperatures but still in the plastic crystalline state, an α1-process takes place. An α2-process was detected using SHS but with a completely different temperature dependence of the relaxation times than that of the α1-relaxation. This result is discussed in detail, and different molecular assignments of the processes are suggested. At even higher temperatures, electrical conductivity is detected and an increase in the DC conductivity by four orders of magnitude at the phase transition from the plastic crystalline to the hexagonal columnar mesophase is found. This result is traced to a change in the charge transport mechanism from a delocalized electron hopping in the stacked aromatic systems (in the plastic phase) to one dominated by an ionic conduction in the quasi-1D ion channels formed along the supermolecular columns in the ILC hexagonal mesophases.
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影响因子：
3.9
作者：
De Cupere, Vinciane;Tant, Julien;Geerts, Yves Henri
通讯作者：
Geerts, Yves Henri
影响因子：
4
作者：
Yoshio, Masafumi;Ichikawa, Takahiro;Kato, Takashi
通讯作者：
Kato, Takashi
影响因子：
15
作者：
Harutoki Shimura;Masafumi Yoshio;K. Hoshino;Tomohiro Mukai;H. Ohno;Takashi Kato
通讯作者：
Harutoki Shimura;Masafumi Yoshio;K. Hoshino;Tomohiro Mukai;H. Ohno;Takashi Kato
具有侧邻三联苯单元的冠醚：酯基和钠盐对介晶性质的影响
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
Nelli Steinke;Michael Jahr;M. Lehmann;Angelika Baro;W. Frey;Stefan Tussetschläger;S. Sauer;S. Laschat
通讯作者：
S. Laschat
通过红外光谱和相关技术研究盘状液晶结构形成的动力学。
影响因子：
3.3
作者：
P. Papadopoulos;C. Grigoriadis;Nino Haase;H. Butt;K. Müllen;G. Floudas
通讯作者：
G. Floudas