A series of novel mesogenic polyesters with 2-dichloromethylhydroquinone moieties were synthesized by polycondensation of the novel diacyl chloride monomer 2-dichloromethyl-1,4-bis (4'-chloroformylbenzoyl) oxybenz...A series of novel mesogenic polyesters with 2-dichloromethylhydroquinone moieties were synthesized by polycondensation of the novel diacyl chloride monomer 2-dichloromethyl-1,4-bis (4'-chloroformylbenzoyl) oxybenzene (I) with alpha, omega-polymethylenediols including ethylene glycol, 1,4-butanediol, 1,6-hexanediol and 1,10-decanediol. The diacyl chloride monomer was synthesized by simultaneous transformations of both the carboxy and formaldehyde groups of 2-formyl-1,4-bis (4'-carboxybenzoyl) oxybenzene into acyl chloride and dichloromethyl groups respectively. The syntheses of the monomer (I) and the polymers were reported.展开更多
The transitions and morphology of a series of main-chain liquid crystalline polymer with X-shaped mesogens were studied by means of DSC,SALS and polarizing microscopy techniques. Aneven-odd effect was observed for sam...The transitions and morphology of a series of main-chain liquid crystalline polymer with X-shaped mesogens were studied by means of DSC,SALS and polarizing microscopy techniques. Aneven-odd effect was observed for samples with different size of the substituents on the mesogenends. The isotropization process was similar to that of main-chain polymers with rod-likemesogens. No crystallization was detected for specimens cooling down from their isotropic meltstate. However two of the samples may crystallize in cooling process directly from the liquidcrystalline state.展开更多
The Photorefractive properties of PVK-based polymeric composites doped with three liquid crystals,4OCB(4-pertyloxy-4'-cyanobiphenyl),5OCB(4-pentyloxy-4'-cyanobiphenyl),8OCB(4-octyloxy-4'-cyanobiphenyl)were...The Photorefractive properties of PVK-based polymeric composites doped with three liquid crystals,4OCB(4-pertyloxy-4'-cyanobiphenyl),5OCB(4-pentyloxy-4'-cyanobiphenyl),8OCB(4-octyloxy-4'-cyanobiphenyl)were investigated by using the two-beam coupling experiment at 633 nm.Gain coefficient over 34 cm^(-1) at an applied field of 60V/μm was observed.Among the three materials,the 8OCB-doped composite demonstrated a stronger orientational effect and the influence on charge field became apparent.展开更多
A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the...A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.展开更多
基金This work was supported by the National Natural Science Foundation of China
文摘A series of novel mesogenic polyesters with 2-dichloromethylhydroquinone moieties were synthesized by polycondensation of the novel diacyl chloride monomer 2-dichloromethyl-1,4-bis (4'-chloroformylbenzoyl) oxybenzene (I) with alpha, omega-polymethylenediols including ethylene glycol, 1,4-butanediol, 1,6-hexanediol and 1,10-decanediol. The diacyl chloride monomer was synthesized by simultaneous transformations of both the carboxy and formaldehyde groups of 2-formyl-1,4-bis (4'-carboxybenzoyl) oxybenzene into acyl chloride and dichloromethyl groups respectively. The syntheses of the monomer (I) and the polymers were reported.
基金This work was supported by the National Natural Science Foundation of China(Grant No.29,070,196)and the Science Foundation of Polymer Physics Laboratory,Academia Sinica.
文摘The transitions and morphology of a series of main-chain liquid crystalline polymer with X-shaped mesogens were studied by means of DSC,SALS and polarizing microscopy techniques. Aneven-odd effect was observed for samples with different size of the substituents on the mesogenends. The isotropization process was similar to that of main-chain polymers with rod-likemesogens. No crystallization was detected for specimens cooling down from their isotropic meltstate. However two of the samples may crystallize in cooling process directly from the liquidcrystalline state.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19974004 and 19525412National Kay Basic Research Special Foundation under Grant No.1999075207.
文摘The Photorefractive properties of PVK-based polymeric composites doped with three liquid crystals,4OCB(4-pertyloxy-4'-cyanobiphenyl),5OCB(4-pentyloxy-4'-cyanobiphenyl),8OCB(4-octyloxy-4'-cyanobiphenyl)were investigated by using the two-beam coupling experiment at 633 nm.Gain coefficient over 34 cm^(-1) at an applied field of 60V/μm was observed.Among the three materials,the 8OCB-doped composite demonstrated a stronger orientational effect and the influence on charge field became apparent.
文摘A group of the mesogen jacketed liquid crystal polymers based on the monomers 2,5-bis (4-substituted benzoyl)oxystyrenes are synthesized. The substituents include alkoxy, alkyl, and cyano groups. The synthesis and the primary characterization of the liquid crystal phase of the monomers and the polymers are described. While some of the monomers give smectic textures the polymers are found to be nematic above their melting or glass transition temperatures. Interestingly the unsubstituted monomer and its polymer poly 2,5-di( benzoyloxy ) styrene are also liquid crystalline. The single crystal structure of one of the monomers is also discussed.
