Dielectric Spectroscopy of Bent-Core Thioesters' B Phases
摘要:
Banana-shaped homologoues 1,3-phenylene bis{4-[(4-alkoxybenzoyl) sulfanyl]benzoate}, in short nOSOR, where n denotes the number of carbon atoms in the end chains, have been studied using dielectric and electrooptic methods. 9OSOR shows a ferroelectric B-1 phase, whereas 12OSOR, 14OSOR exhibit antiferroelectric B-2 phase. Dielectric spectra have been measured for two alignments of B-2 phase. In the low frequency range a broad collective relaxation process is observed under bias field. This process is connected with fluctuations of ferroelectric domains. The high frequency relaxation originates from molecular reorientation around the long axis.
Dielectric Spectroscopy of Bent-Core Thioesters' B Phases
摘要:
Banana-shaped homologoues 1,3-phenylene bis{4-[(4-alkoxybenzoyl) sulfanyl]benzoate}, in short nOSOR, where n denotes the number of carbon atoms in the end chains, have been studied using dielectric and electrooptic methods. 9OSOR shows a ferroelectric B-1 phase, whereas 12OSOR, 14OSOR exhibit antiferroelectric B-2 phase. Dielectric spectra have been measured for two alignments of B-2 phase. In the low frequency range a broad collective relaxation process is observed under bias field. This process is connected with fluctuations of ferroelectric domains. The high frequency relaxation originates from molecular reorientation around the long axis.
作者:J. C. Rouillon、J. P. Marcerou、M. Laguerre、H. T. Nguyen、M. F. Achard
DOI:10.1039/b103143k
日期:2001.11.23
A new series of achiral banana-shaped compounds ("S-n'') has been synthesised and studied by the classical techniques (optical microscopy, differential scanning calorimetry, X-ray diffraction and electro-optic investigations). The short homologues (S-6,S-7) present an intercalated smectic B6 and a two-dimensional B1 phase. The intermediate S-8-S-10 compounds only form a B1 phase while the mesophase of long homologues (S-11-S-16) is identified as a switchable smectic B2 mesophase.