Browsing by Author "CHEN, YN"

Now showing 1 - 4 of 4

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.
SYNTHESIS AND CHARACTERIZATION OF NOVEL FLUORINATED DIPHENYLDIACETYLENIC LIQUID-CRYSTALS
(1993-10-01)
JUANG, TM
;
CHEN, YN
;
LUNG, SH
;
LU, YH
;
HSU, CS
Five series of asymmetric diphenyldiacetylenes containing a single fluorine, two fluorines or a trifluoromethyl group at one end and an alkyl, alkyloxy or alkenyloxy group on the other end, were prepared and characterized. Most of the 4-alkylphenyl-4'-fluorophenyldiacetylenes, 4-alkyloxyphenyl-4'-fluorophenyl-diacetylenes and 4-alkenyloxyphenyl-4'-fluorophenyldiacetylenes obtained exhibit an enantiotropic nematic phase and no smectic phase. However, most of the 4-alkyl-3', 4'-difluorodiphenyldiacetylenes, 4-alkenyloxy-3',4'-difluorodiphenyl-diacetylenes and 4-alkyl-4'-trifluoromethyldiphenyldiacetylenes show no meso-morphic behaviour. The effects of alkyl, alkyloxy, alkenyloxy, fluoro, 3,4-difluoro and trifluoromethyl end groups on the mesomorphic behaviour of the diphenyldiacetylenes prepared are discussed.
SYNTHESIS OF LIQUID-CRYSTALLINE POLYSILOXANES CONTAINING DIPHENYLDIACETYLENE SIDE GROUPS
(1992-08-23)
HSU, CS
;
LU, YH
;
CHEN, YN
;
應用化學系
;
Department of Applied Chemistry