A novel series of chiral dopants synthesized from(S)-1,2-propanediol and mesogenic carboxylic acids were characterized by FT-IR,~1H NMR,elemental analysis and their helical twisting properties were investigated by dop...A novel series of chiral dopants synthesized from(S)-1,2-propanediol and mesogenic carboxylic acids were characterized by FT-IR,~1H NMR,elemental analysis and their helical twisting properties were investigated by doping the chiral dopants into a nematic liquid crystal host(SLC-1717).The results show that,the helical pitch of N~*-LC mixture exhibited a terminal alkyl chain length dependence and the molecular twisting power β also exhibited a temperature dependence(increasing β with increasing temperature).展开更多
In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction betweefi optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR, ^1H NMR, elemental a...In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction betweefi optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR, ^1H NMR, elemental analysis, SEM, UV absorption spectrum. After dissolving in a nematic liquid crystal mixture, the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture. Meanwhile, a relatively high value of helical twisting power of the polymerizable chiral dopant was determined. The results show that the chiral dopant has great potential in achieving a polymer stabilized chiral nematic liquid crystal film with a broad-band selective reflection. C 2009 Huai Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The phase transition behavior and aggregating states of [smectic LCP, PS(4BC/DM)/nematic LC, E7/chiral dopant, CB 15] ternary composite system were investigated on the basis of differential scanning calorimetry (DSC)...The phase transition behavior and aggregating states of [smectic LCP, PS(4BC/DM)/nematic LC, E7/chiral dopant, CB 15] ternary composite system were investigated on the basis of differential scanning calorimetry (DSC) measurement, polarizing optical microscopy (POM) observation and wide angle X ray diffraction (WAXD) patterns. It was demonstrated that if the weight ratio of the chiral dopant was fixed as 4.8wt%, an induced chiral nematic (N *) phase existed in the ternary system when PS(4BC/DM) ratio was below 47.6 wt%. Moreover, smectic like long range ordering appeared in the induced N * phase in a certain temperature range just above the smectic A(S A) N * phase transition when PS(4BC/DM) ratio was between 19.1wt% and 47.6wt%.展开更多
1 Introduction A particularly efficient and elegant route to chiral mesophases is based on the addition of small amounts of an enantiomerically pure dopant to a nematic phase so that the latter is converted into a cho...1 Introduction A particularly efficient and elegant route to chiral mesophases is based on the addition of small amounts of an enantiomerically pure dopant to a nematic phase so that the latter is converted into a cholesteric phase(See Fig.1).Fig.1 A nematic phase is converted into a cholesteric phase Fig.2 Bis-chelated imine-alkoxy-titanium complexes2 ExperimetalBis-chelated imine-alkoxy-titanium complexes like 1 and 2 (Fig.2) have been synthesizedstarting from triphenyl-substituted aminoethanols, T...展开更多
In this study, a novel series of chiral 1,2-propanediol derivatives with different terminal alkyl chain length were synthesized and characterized by FT-IR, ^1H NMR and DSC. After doped into a nematic liquid crystal ho...In this study, a novel series of chiral 1,2-propanediol derivatives with different terminal alkyl chain length were synthesized and characterized by FT-IR, ^1H NMR and DSC. After doped into a nematic liquid crystal host, all the chiral dopants induced chiral nematic liquid crystals exhibiting a helix inversion with temperature variation. The results indicate that terminal alkyl chain length has a prominent influence on helical twisting property of the chiral dopants. With increasing the terminal alkyl chain length, the molecular twisting power increases, the helix inversion temperatures varies slightly while the phase transition temperature decreases. An odd-even effect may exist in the molecular twisting power of the chirai dopants.展开更多
基金the National Science Foundation(No.20674005)the Flat-Panel Display Special Project of China 863 Plan(No.2008AA03A318)Projects of Chinese National Science and Technology Tackling Key Problems(No.2007BAE31B02)
文摘A novel series of chiral dopants synthesized from(S)-1,2-propanediol and mesogenic carboxylic acids were characterized by FT-IR,~1H NMR,elemental analysis and their helical twisting properties were investigated by doping the chiral dopants into a nematic liquid crystal host(SLC-1717).The results show that,the helical pitch of N~*-LC mixture exhibited a terminal alkyl chain length dependence and the molecular twisting power β also exhibited a temperature dependence(increasing β with increasing temperature).
基金supported by the National Basic Research Program of China(No.2007CB613301)the National Natural Science Foundation(No.20674005)the Program of Beijing Municipal Science and Technology(No.Y0405004040121).
文摘In this study, right-handed dicinnamate isosorbide was synthesized via the esterification reaction betweefi optically active isosorbide and cinnamate. The chiral dopant was characterized by FT-IR, ^1H NMR, elemental analysis, SEM, UV absorption spectrum. After dissolving in a nematic liquid crystal mixture, the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture. Meanwhile, a relatively high value of helical twisting power of the polymerizable chiral dopant was determined. The results show that the chiral dopant has great potential in achieving a polymer stabilized chiral nematic liquid crystal film with a broad-band selective reflection. C 2009 Huai Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘The phase transition behavior and aggregating states of [smectic LCP, PS(4BC/DM)/nematic LC, E7/chiral dopant, CB 15] ternary composite system were investigated on the basis of differential scanning calorimetry (DSC) measurement, polarizing optical microscopy (POM) observation and wide angle X ray diffraction (WAXD) patterns. It was demonstrated that if the weight ratio of the chiral dopant was fixed as 4.8wt%, an induced chiral nematic (N *) phase existed in the ternary system when PS(4BC/DM) ratio was below 47.6 wt%. Moreover, smectic like long range ordering appeared in the induced N * phase in a certain temperature range just above the smectic A(S A) N * phase transition when PS(4BC/DM) ratio was between 19.1wt% and 47.6wt%.
文摘1 Introduction A particularly efficient and elegant route to chiral mesophases is based on the addition of small amounts of an enantiomerically pure dopant to a nematic phase so that the latter is converted into a cholesteric phase(See Fig.1).Fig.1 A nematic phase is converted into a cholesteric phase Fig.2 Bis-chelated imine-alkoxy-titanium complexes2 ExperimetalBis-chelated imine-alkoxy-titanium complexes like 1 and 2 (Fig.2) have been synthesizedstarting from triphenyl-substituted aminoethanols, T...
基金supported by the National Natural Science Foundation(No.20674005)the Flat-Panel Display Special Project of China 863 Plan(No.2008AA03A318)+1 种基金Projects of Chinese National Science and Technology Tackling Key Problems(No.2007BAE31B02)Program of National Laboratory of Electro-Optics System Technology(No.9140C150102090C1501).
文摘In this study, a novel series of chiral 1,2-propanediol derivatives with different terminal alkyl chain length were synthesized and characterized by FT-IR, ^1H NMR and DSC. After doped into a nematic liquid crystal host, all the chiral dopants induced chiral nematic liquid crystals exhibiting a helix inversion with temperature variation. The results indicate that terminal alkyl chain length has a prominent influence on helical twisting property of the chiral dopants. With increasing the terminal alkyl chain length, the molecular twisting power increases, the helix inversion temperatures varies slightly while the phase transition temperature decreases. An odd-even effect may exist in the molecular twisting power of the chirai dopants.
