作者:Vladimíra Novotná、Věra Hamplová、Natalia Podoliak、Miroslav Kašpar、Milada Glogarová、Damian Pociecha、Ewa Gorecka
DOI:10.1039/c1jm12131f
日期:——
Unusual mesomorphic behaviour has been found in a series of rod-like liquid crystalline (LC) compounds with two chiral centres in the molecular chain. A re-entrant paraelectric SmA* (SmA*RE) phase has been discovered below the ferroelectric SmC* phase on cooling for one homologue. So far this compound is the only one exhibiting the re-entrancy of the smectic A phase in chiral LC system with structural parameters so close to the upper SmA* phase. X-Ray studies, as well as dielectric spectroscopy, spontaneous polarization and tilt angle measurements have been carried out to characterize studied compounds. We compare various homologues and look for tendencies in physical properties behaviour.
在一系列具有两个手性中心的棒状液晶(LC)化合物中,发现了不寻常的中间相行为。我们在冷却过程中发现了一个回返型顺电SmA*(SmA*RE)相,该相位位于铁电SmC*相的下方。目前,这种化合物是唯一展现出在结构参数与上层SmA*相非常接近的手性液晶系统中分层A相回返现象的化合物。研究还进行了X射线研究、介电光谱、自发极化和倾斜角度测量,以表征所研究的化合物。我们比较了不同的同系物,并寻找物理性质行为的趋势。