Browsing by Author "WU, ST"

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FLUORINATED DIPHENYL-DIACETYLENE AND TOLANE LIQUID-CRYSTALS WITH LOW THRESHOLD VOLTAGE
(1992-11-09)
WU, ST
;
HSU, CS
;
CHEN, YN
;
WANG, SR
;
應用化學系
Several new fluoro-alkoxy and alkenyloxy (alkoxy with a carbon-carbon double bond) diphenyl-diacetylene and tolane liquid crystals are synthesized and their physical properties evaluated. Double bond position is found to make a pronounced effect on elastic constant, phase transition temperature and heat fusion enthalpy, but little change on birefringence, dielectric anisotropy, and viscosity. These compounds exhibit a high birefringence, low viscosity, and low threshold voltage, and are particularly attractive for infrared light valves and polymer-dispersed liquid crystal displays.
FLUORODIPHENYLDIACETYLENE AND TOLANE LIQUID-CRYSTALS FOR DISPLAY APPLICATION
(1993-08-01)
WU, ST
;
HSU, CS
;
CHEN, YN
;
WANG, SR
;
LUNG, SH
Several fluorinated diphenyldiacetylene and tolane liquid crystals are synthesized and their physical properties evaluated. These liquid crystals exhibit a high resistivity, high birefringence, low viscosity, and modest dielectric anisotropy. Some difluoro compounds show a relatively low melting temperature and small heat fusion enthalpy and are useful for formulating eutectic mixtures. The mixtures consisting of these fluorinated compounds are particularly useful for active matrix, photoactivated light valve, and polymer-dispersed liquid crystal displays.
ROOM-TEMPERATURE DIPHENYL-DIACETYLENE LIQUID-CRYSTALS
(1992-08-10)
WU, ST
;
MARGERUM, JD
;
MENG, HB
;
DALTON, LR
;
HSU, CS
Thirty new asymmetric diphenyl-diacetylene (PTTP) liquid-crystal homologs are synthesized and their physical properties characterized. In addition to the observed high birefringence and relatively low viscosity, several dialkyl PTTP homologs also possess a low melting point, wide nematic range, and low heat of fusion enthalpy. These properties are highly desirable for forming eutectic mixtures with entirely PTTP components. A binary eutectic showing a nematic range from 10 to 98-degrees-C is studied. These new liquid-crystal compounds and mixtures should be particularly useful for infrared applications.
SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTALLINE MONOMERS AND SIDE-CHAIN POLYMERS CONTAINING DIPHENYLDIACETYLENE MESOGENS
(1993)
LU, YH
;
HSU, CS
;
WU, ST
;
應用化學系
;
Department of Applied Chemistry
Nine unsymmetrically diphenyldiacetylenic monomers were prepared. The phase behavior as well as thermal polymerization of the obtained monomers were characterized by optical polarizing microscopy and DSC measurement. UV absorption, refractive indices and dielectric constants of the monomers were also measured. The olefinic monomers were subjected to undergo hydrosilylation reaction with poly(methylhydrogensiloxane) to form the polysiloxanes. Thermal behavior of the prepared polysiloxanes were studied.
SYNTHESIS OF FLUORINATED NAPHTHYLPHENYLACETYLENIC AND NAPHTHYLPHENYLDIACETYLENIC LIQUID-CRYSTALS
(1995-10-01)
HSU, CS
;
TSAY, KT
;
CHANG, AC
;
WANG, SR
;
WU, ST
Four series of fluorinated tolanes, naphthylphenylacetylenes and naphthylphenyldiacetylenes were prepared and characterized. Most of the fluorinated tolanes exhibit no mesomorphic behaviour. However, most of the fluorinated naphthylphenylacetylenes and naphthylphenyldiacetylenes form enantiotropic nematic phases. The dielectric anisotropy and birefringence of some selected compounds were measured by a guest-host method. All of those studied show relatively high dielectric anisotropy and birefringence.
SYNTHESIS OF FLUORINATED NAPHTHYLPHENYLACETYLENIC AND NAPHTHYLPHENYLDIACETYLENIC LIQUID-CRYSTALS
(1995-10-01)
HSU, CS
;
TSAY, KT
;
CHANG, AC
;
WANG, SR
;
WU, ST
Four series of fluorinated tolanes, naphthylphenylacetylenes and naphthylphenyldiacetylenes were prepared and characterized. Most of the fluorinated tolanes exhibit no mesomorphic behaviour. However, most of the fluorinated naphthylphenylacetylenes and naphthylphenyldiacetylenes form enantiotropic nematic phases. The dielectric anisotropy and birefringence of some selected compounds were measured by a guest-host method. All of those studied show relatively high dielectric anisotropy and birefringence.