Electrooptic and Dielectric Spectroscopy Measurements of Binary Chiral-Dopant Antiferroelectric Mixtures
作者:
DevenD. Parghi,
JanP. F. Lagerwall,
Gerd Heppke,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 2000)
卷期:
Volume 351,
issue 1
页码: 361-370
ISSN:1058-725X
年代: 2000
DOI:10.1080/10587250008023286
出版商: Taylor & Francis Group
关键词: liquid crystal;antiferroelectric;chiral-dopant mixture;dielectric spectroscopy;electrooptics
数据来源: Taylor
摘要:
Recent examinations on binary chiral-dopant antiferroelectric liquid crystalline mixtures revealed an unusual switching behaviour. In order to investigate the switching processes that take place in the mixtures, both in the bulk and as influenced by surfaces, further electrooptic and dielectric spectroscopy studies have been carried out on two model binary mixtures in the induced SmA*, SmC* and SmCA* phases. The dielectric spectra feature the different modes typical for these phases, but of varying purity, indicating a more complex phase behaviour than expected. The electrooptic behaviour in the antiferroelectric phase varied from clearly antiferroelectric to near hysteresis-free switching directly between ferroelectric states. We conclude that the phase sequence, and consequently switching behaviour, is a function of both the type of dopant used and of the strength of the surface interactions (cell thickness). In thin cells synclinic (ferroelectric) ordering appears to be favoured.
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