Dynamics of electric-field-induced molecular reorientation and segmental mobility in the smectic-C^{*} phase of a ferroelectric liquid crystal: Faster reorientation of cores than the alkyl chains revealed by time-resolved infrared spectroscopy

1997 ◽  
Vol 56 (3) ◽  
pp. 3053-3060 ◽  
Author(s):  
A. Verma ◽  
B. Zhao ◽  
S. Jiang ◽  
J. Sheng ◽  
Y. Ozaki
Keyword(s):  
Infrared Spectroscopy ◽  
Liquid Crystal ◽  
Electric Field ◽  
Ferroelectric Liquid Crystal ◽  
Segmental Mobility ◽  
Molecular Reorientation ◽  
Time Resolved ◽  
Alkyl Chains ◽  
Smectic C ◽  
Time Resolved Infrared Spectroscopy

Submicrosecond Preliminary Process of Electric-Field-Induced Reorientation of a Ferroelectric Liquid Crystal, 5-(2-Fluoroalkoxy)-2-(4-n-Alkylphenyl)-Pyrimidine, Studied by Time-Resolved Infrared Spectroscopy

1995 ◽  
Vol 49 (7) ◽  
pp. 977-980 ◽  
Author(s):  
Norihisa Katayama ◽  
Takashi Sato ◽  
Yukihiro Ozaki ◽  
Katsuyuki Murashiro ◽  
Makoto Kikuchi ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Delay Time ◽  
Strong Influence ◽  
Spectroscopic Technique ◽  
Ferroelectric Liquid Crystal ◽  
Time Resolved ◽  
Rigid Rod ◽  
Time Resolved Infrared Spectroscopy ◽  
Reorientation Process

Pulsed electric-field-induced reorientation of a ferroelectric liquid crystal (FLC), 5-(2-fluorooctyloxy)-2-(4-hexylphenyl)-pyrimidine, has been investigated by using a dispersive submicrosecond time-resolved infrared spectroscopic technique. The observed absorbance decay for a band at 1440 cm−1 due to a ring-stretching mode of the phenylpyrimidine group indicates that the FLC molecule reorients from a stationary state with a slight delay (less than 1 μs) just after the upswing of the electric field, while counter-reorientation occurs with a delay time of a microsecond after the reverse of the electric field. The delay time for the counter-reorientation changes with temperature, indicating that the viscosity has a strong influence on the delay time. It is also indicated in the present study that the whole FLC molecule reorients simultaneously as a rigid rod in both the preliminary and the counter-reorientation process.

Vibrational Studies on the Dynamics of Switching between the Surface-Stabilized States of a Ferroelectric Liquid Crystal by Asynchronous Time-Resolved Fourier Transform Infrared Spectroscopy

1993 ◽  
Vol 47 (9) ◽  
pp. 1370-1375 ◽  
Author(s):  
Koji Masutani ◽  
Akira Yokota ◽  
Yukio Furukawa ◽  
Mitsuo Tasumi ◽  
Atsushi Yoshizawa
Keyword(s):  
Liquid Crystal ◽  
Time Behavior ◽  
Ferroelectric Liquid Crystal ◽  
Slow Process ◽  
Fast Process ◽  
Time Resolved ◽  
Smectic C ◽  
Rigid Molecule ◽  
Vibrational Studies

Time-resolved polarized infrared spectra have been observed from a ferroelectric liquid crystal (chiral smectic C phase) consisting of a chiral dopant and a nonchiral smectic base during the course of switching between the surface-stabilized states. A primary fast process and the subsequent slow process have been observed for all infrared bands. The chiral dopant and smectic base molecules move simultaneously. The observed time behavior of the infrared bands can be mostly explained by the reorientation of a rigid molecule whose rotational motion around the molecular long axis is almost free. The static intensities and the time behavior of the ester and keto C=O stretching bands do not seem to be consistent with the simple view on the role of these groups.

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