X-ray diffraction and dielectric spectroscopy studies on a partially fluorinated ferroelectric liquid crystal from the family of terphenyl esters

2012 ◽  
Vol 39 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
S. Haldar ◽  
K.C. Dey ◽  
D. Sinha ◽  
P.K. Mandal ◽  
W. Haase ◽  
...  
Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1498
Author(s):  
Alexej Bubnov ◽  
Alexey Bobrovsky ◽  
Ivan Rychetský ◽  
Ladislav Fekete ◽  
Věra Hamplová

The control and prediction of soft systems exhibiting self-organization behavior can be realized by different means but still remains a highlighted task. Novel advanced nanocomposite system has been designed by filling of a stretched porous polyethylene (PE) film with pore dimensions of hundreds of nanometers by chiral ferroelectric liquid crystalline (LC) compound possessing polar self-assembling behavior. Lactic acid derivative exhibiting the paraelectric orthogonal smectic A* and the ferroelectric tilted smectic C* phases over a broad temperature range is used as a self-assembling compound. The morphology of nanocomposite film has been checked by Atomic Force Microscopy (AFM). The designed nanocomposite has been studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), small and wide-angle X-ray scattering and broadband dielectric spectroscopy. The effect of a porous PE confinement on self-assembling, structural, and dielectric behavior of the chiral LC compound has been established and discussed. While the mesomorphic and structural properties of the nanocomposite are found not to be much influenced in comparison to that of a pure LC compound, the polar properties have been toughly suppressed by the specific confinement. Nevertheless, the electro-optic switching was clearly observed under applied electric field of low frequency (210 V, 19 Hz). The dielectric spectroscopy and X-ray results reveal that the helical structure of the ferroelectric liquid crystal inside the PE matrix is completely unwound, and the molecules are aligned along stretching direction. Obtained results demonstrate possibilities of using stretched porous polyolefins as promising matrices for the design of new nanocomposites.


2006 ◽  
Vol 33 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Jan P. F. Lagerwall ◽  
David Coleman ◽  
Eva Körblova ◽  
Chris Jones ◽  
Renfan Shao ◽  
...  

2004 ◽  
Vol 19 (1) ◽  
pp. 53-55 ◽  
Author(s):  
Kazuhiro Takada ◽  
Takashi Noma ◽  
Takeshi Togano ◽  
Taihei Mukaide ◽  
Atsuo Iida

Local layer structures and their formation process in a half-V-shaped switching ferroelectric liquid crystal (HV-FLC) were investigated by means of synchrotron X-ray microdiffraction. The HV-FLC is a FLC that has a cholesteric–chiral smectic C (Ch–SmC*) phase transition sequences. X-ray microdiffraction measurements revealed that the SmC* phase in the HV-FLC was composed of asymmetric chevron and inclined-bookshelf structures. In addition, temperature-controlled X-ray diffraction measurements showed that the transient layer structures appeared during the Ch to SmC* phase transition.


2003 ◽  
Vol 18 (4) ◽  
pp. 293-295 ◽  
Author(s):  
L. Dobiášová ◽  
H. Šíchová ◽  
V. Valvoda

The ferroelectric liquid crystal material [4-[(4-methyloxyfenyl) carbonyloxyl] bifenyl-4′-yl]-(S)-2-methylbutoxypropionate containing a lateral methyl group on the aromatic ring of the alkoxybenzoate unit and two chiral carbons has been investigated by X-ray powder diffraction analysis at the 28 °C–105 °C temperature range. On cooling through the SmC temperature range, the layer spacing decreases from 28.3 to 27.7 Å with a small variation of average intermolecular distances. Lattice parameters of tetragonal and monoclinic crystalline phases occurring at lower temperatures have been determined.


1984 ◽  
Vol 4 (3) ◽  
pp. 225-239
Author(s):  
M. Hidaka ◽  
H. Akiyama ◽  
S. Kai ◽  
M. Iwasaki

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