研究目的
Investigating the dual-frequency nematic liquid crystals (DFNLCs) doped with dichroic dye through dielectric spectroscopy and optical characterisation.
研究成果
The study observed a wide difference between the two pure mixtures 1832B and 1909C in term of permittivity, crossover frequencies and molecular behaviour. The lowest value of the crossover frequency (should be below 1 kHz at room temperature) is preferred from the application point of view, as in a fast switching device, a tunable photonic device or a light modulator. Regarding the optical characterisation, a Stable Focal Conic State and Unstable Focal Conic State were found for the doped mixtures 1832B and 1909C, respectively.
研究不足
The presence of some impurity (ions) that the dichroic dye introduces in the mixture affects the measurements. Additionally, dielectric spectroscopy measurements have been difficult to implement with the same technique applied up to now due to more impurities added by dichroic dye.
1：Experimental Design and Method Selection:
The study involved dielectric spectroscopy and optical characterisation of two pure and doped mixtures of DFNLCs.
2：Sample Selection and Data Sources:
Two mixtures of DFNLCs, 1832B and 1909C, were prepared at the Institute of Chemistry of the Military University of Technology (MUT).
3：List of Experimental Equipment and Materials:
Dielectric investigations were performed with an impedance analyser HP
4：Optical characterisation was performed using a bipolar Pi polarising microscope, LINKAM HMSE600 heating plate, and a source of white light. Experimental Procedures and Operational Workflow:
41 The study started the measure from isotropic phase to crystalline phase in a step rate
5：3°C/min and made a sweep frequency from 100 Hz to 10 MHz. Temperature was controlled by Linkam TMS 92 temperature controller. Data Analysis Methods:
The real ε0 and imaginary ε00 part of permittivity of liquid crystals was obtained from capacity C(f) and conductivity G(f) determined as a function of frequency.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容-
data reading computer system
TDS 2014
Tectronix
Data acquisition
-
impedance analyser
HP 4192
HP
Dielectric investigations
-
polarising microscope
bipolar Pi
Optical characterisation
-
heating plate
LINKAM HMSE600
LINKAM
Temperature control
-
temperature controller
Linkam TMS 92
Linkam
Temperature control
-
heating/cooling stage
Linkam THMS-600
Linkam
Temperature control
-
function/arbitrary waveform generator
HP 33120A
HP
Generating electrical signals
-
high voltage amplifier
F20A
FLC electronics
Amplifying electrical signals
-
photo-oscilloscope
PIN 20
FLC electronics
Recording optical response
-
ultrasonic welding tool
USS-9200
MBR Electronics
Welding
-
登录查看剩余8件设备及参数对照表
查看全部
