Ferroelectric and antiferroelectric low molar mass organosiloxane liquid crystals
作者:
W. K. ROBINSON,
C. CARBONI,
P. KLOESS,
S. P. PERKINS,
H. J. COLES,
期刊:
Liquid Crystals
(Taylor Available online 1998)
卷期:
Volume 25,
issue 3
页码: 301-307
ISSN:0267-8292
年代: 1998
DOI:10.1080/026782998206092
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The present paper is a study of the ferroelectric and antiferroelectric behaviour in low molar mass organosiloxane liquid crystal materials classed as mono-mesogens (AB type) and bi-mesogens (ABA type). A systematic study of series of materials all based on the same chiral mesogenic moiety is presented. The mesogen is a biphenylyl benzoate with a halogen X attached laterally to the benzoate ring which is closest to the chiral centre. Three homologous series, where the halogen is either fluorine, chlorine or bromine, are investigated. The number of silicon atoms in the linkage or end group is varied between two and nine. It is found that the materials have a broad (40 C) ferroelectric or antiferroelectric phase with a high P s (90nC cm2). The siloxane moiety forces the tilt angle to a temperature independent value close to 45. The antiferroelectric order is observed only in bi-mesogens with an odd number of silicon atoms in the siloxane link. The antiferroelectric order is attributed to the conformation of the molecule rather than to antiferroelectric interactions between layers.
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