The methacrylate monomers bearing mesogenic group and heterocyclicazo dye have been synthesized. The monomeric dye was copolymerized with the mesogenicmonomer using a free radical initiator to produce polymers useful ...The methacrylate monomers bearing mesogenic group and heterocyclicazo dye have been synthesized. The monomeric dye was copolymerized with the mesogenicmonomer using a free radical initiator to produce polymers useful for nonlinear optics. Themonomers and polymers were characterized by IR,;H-NMR, and UV-Vis spectra. Theaverage molecular weight （M;and M;） of the polymers were determined by gel permeationchromatography. The thermal properties of the polymers such as thermal stability andphase transition behavior were studied by thermogravimetric analysis, differential thermalanalysis, polarizing optical microscope and X-ray diffractometer. The results demonstratethat the synthesized polymers are crystalline polymers at room temperature and no liquidcrystalline phases were observed for all of them.展开更多
The synthesis and characterization of a series of novel comb-like polymethacrylates bearing heterocyclic azo group and mesogenic group are described. The thermal properties of the polymers such as thermal stability an...The synthesis and characterization of a series of novel comb-like polymethacrylates bearing heterocyclic azo group and mesogenic group are described. The thermal properties of the polymers such as thermal stability and phase transition behavior were investigated by thermogravimetric analysis, differential thermal analysis and polarizing optical microscopy techniques. The experimental results show that all the synthesized polymers do not exhibit liquid crystallinity except the homopolymer of the mesogenic monomer MAPB2 and the glass transition temperatures of the polymers increase with increasing content of azo moiety in polymers linearly.展开更多
Metal-and oxidant-free alkenyl C–H thiolation enabled by the azo group had been established for the modular synthesis of tetrasubstituted acyclic olefins.The reaction was performed under mild reaction conditions with...Metal-and oxidant-free alkenyl C–H thiolation enabled by the azo group had been established for the modular synthesis of tetrasubstituted acyclic olefins.The reaction was performed under mild reaction conditions with a broad substrate scope.The intramolecular 6-membered hydrogen-bonding network accounts for the observed excellent stereo-control.展开更多
The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter hea...The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter heating for 10 min at 70℃ the multilayer film became very stable towards po lar solvents.No considerable changes were observed for the heated film soaked i n DMF (20℃) for 48 h,while the unheated film almost destroyed at same conditio n.The dramatic improvement in stability of the film towards polar solvents shou ld be attributed to the conversion of bonds between the layers of the film from ionic bond to covalent bond under heating.Y(4 DIAZONIUMSTYRENE)ANDPOLY(SODIUMSULFONATESTYRENE)YANGZhaohui,JIANGWei,CAOWeixiao(CollegeofChemistryandMolecularEngineering ,PekingUniversity ,Beijing 10 0 871)Abstract Theself assemblybetweenpoly( 4 diazoniumstyrene) (PDS)andpoly(sodiumsulfonatestyrene) (PSS)wasinvestigated .Themutilayerultrathinfilmswerefabricatedlayer by layersuccessfullyfromPDSandPSS .Afterheatingfor 1 0minat 70℃themultilayerfilmbecameverystabletowardspolarsolvents.NoconsiderablechangeswereobservedfortheheatedfilmsoakedinDMF ( 2 0℃ )for48h ,whiletheunheatedfilmalmostdestroyedatsamecondition.Thedramaticimprovementinstabilityofthefilmtowardspolarsolventsshouldbeattributedtotheconversionofbondsbetweenthelayersofthefilmfromionicbondtocovalentbondunderheating .Keywords Poly( 4 diazoniumstyrene) 。展开更多
文摘The methacrylate monomers bearing mesogenic group and heterocyclicazo dye have been synthesized. The monomeric dye was copolymerized with the mesogenicmonomer using a free radical initiator to produce polymers useful for nonlinear optics. Themonomers and polymers were characterized by IR,;H-NMR, and UV-Vis spectra. Theaverage molecular weight （M;and M;） of the polymers were determined by gel permeationchromatography. The thermal properties of the polymers such as thermal stability andphase transition behavior were studied by thermogravimetric analysis, differential thermalanalysis, polarizing optical microscope and X-ray diffractometer. The results demonstratethat the synthesized polymers are crystalline polymers at room temperature and no liquidcrystalline phases were observed for all of them.
文摘The synthesis and characterization of a series of novel comb-like polymethacrylates bearing heterocyclic azo group and mesogenic group are described. The thermal properties of the polymers such as thermal stability and phase transition behavior were investigated by thermogravimetric analysis, differential thermal analysis and polarizing optical microscopy techniques. The experimental results show that all the synthesized polymers do not exhibit liquid crystallinity except the homopolymer of the mesogenic monomer MAPB2 and the glass transition temperatures of the polymers increase with increasing content of azo moiety in polymers linearly.
基金Financial support from the Natural Science Foundation of Henan Province(No.222300420084)application research plan for key scientific research projects in colleges and universities of Henan Province(No.22A150056)Zhengzhou University(JC22261005),and the National Natural Science Foundation of China(No.21871237)are gratefully acknowledged.
文摘Metal-and oxidant-free alkenyl C–H thiolation enabled by the azo group had been established for the modular synthesis of tetrasubstituted acyclic olefins.The reaction was performed under mild reaction conditions with a broad substrate scope.The intramolecular 6-membered hydrogen-bonding network accounts for the observed excellent stereo-control.
文摘The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter heating for 10 min at 70℃ the multilayer film became very stable towards po lar solvents.No considerable changes were observed for the heated film soaked i n DMF (20℃) for 48 h,while the unheated film almost destroyed at same conditio n.The dramatic improvement in stability of the film towards polar solvents shou ld be attributed to the conversion of bonds between the layers of the film from ionic bond to covalent bond under heating.Y(4 DIAZONIUMSTYRENE)ANDPOLY(SODIUMSULFONATESTYRENE)YANGZhaohui,JIANGWei,CAOWeixiao(CollegeofChemistryandMolecularEngineering ,PekingUniversity ,Beijing 10 0 871)Abstract Theself assemblybetweenpoly( 4 diazoniumstyrene) (PDS)andpoly(sodiumsulfonatestyrene) (PSS)wasinvestigated .Themutilayerultrathinfilmswerefabricatedlayer by layersuccessfullyfromPDSandPSS .Afterheatingfor 1 0minat 70℃themultilayerfilmbecameverystabletowardspolarsolvents.NoconsiderablechangeswereobservedfortheheatedfilmsoakedinDMF ( 2 0℃ )for48h ,whiletheunheatedfilmalmostdestroyedatsamecondition.Thedramaticimprovementinstabilityofthefilmtowardspolarsolventsshouldbeattributedtotheconversionofbondsbetweenthelayersofthefilmfromionicbondtocovalentbondunderheating .Keywords Poly( 4 diazoniumstyrene) 。
