Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tribu...Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tributylstannyl） ethylene （monomer 2）. The polymers with alkoxy groups are soluble in common organic solvents and exhibit blue fluorescence. Both the cast film and the annealed film have large red-shifts in fluorescence spectra and show yellow fluorescence. The polymers with CN and NO2 groups show poor solubility and green fluorescence. All the polymers possess liquid crystalline smectic phases. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The polymers are easily aligned under a magnetic field of 10 Tesla. It is found that the conjugated backbone and LC side chain are aligned perpendicular and parallel to the magnetic field, respectively. The polymers show optical dichroism in fluorescence spectra, suggesting that they are available for advance materials with linear optical polarization.展开更多
A series of poly（p-phenylenevinylene）s （PPVs） with good solubility were synthesized from thermal elimination of precursor poly（2,5-didodecyloxy-p-phenylenevinylene） at different temperature via Wessling method. ...A series of poly（p-phenylenevinylene）s （PPVs） with good solubility were synthesized from thermal elimination of precursor poly（2,5-didodecyloxy-p-phenylenevinylene） at different temperature via Wessling method. The polymer photophysics were influenced by the thermal elimination condition, which was consistent with NMR and IR characterizations. The additional absorption peak at longer wavelength and the red-shifted emission maximum both in solution and in film, for PPVs obtained at high elimination temperature, indicated the existence of longer conjugated blocks in these systems. The emission maximum for drop-cast film （436 nm） for PPV obtained under 200 ℃ （PPV200） was 16 nm blue shifted to the spin-coated films （452 nm） or 29 nm to the solution （465 nm）. The SEM study showed drop-cast film had the morphology of isolated conjugated particles in the matrix while blurry linear structure was found for spin-coated film, which was consistent with the photophysics. The discussion about this difference was carried out based on the consideration of the flexibility of the polymer chains and different conjugated length of PPV in different states.展开更多
A cationic poly(p-phenylene vinylene) related copolymer without bulky phenylene substitutents attached to the conjugated backbone was prepared through Wittig reaction.The molecular structure and optical properties wer...A cationic poly(p-phenylene vinylene) related copolymer without bulky phenylene substitutents attached to the conjugated backbone was prepared through Wittig reaction.The molecular structure and optical properties were highly investigated through ~1H-NMR,UV and PL spectroscopy.The quenching behavior was also investigated,and the results demonstrate that incomplete quenching exists,which is consistent with the cationic poly(p-phenylene vinylene) related copolymer containing bulky phenylene substitutents,prob...展开更多
Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing l...Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing length of the flexible blocks. Bright blue-light emitting diodes were fabricated using PPV copolymers as electroluminescent layers. The devices show 190 cd/m2 light-emitting brightness at 460 nm and 15 V turn-on voltage. The effects of oxadiawle derivative PBD and tris(8-hydroxyquinoline) aluminum Alq3 electron-transporting layers on the luminance and stability of the devices are discussed.展开更多
通过Gilch反应合成了结构新颖、含四官能团单元的超支化PPV聚合物P1～P3.聚合物的结构得到1 H NMR和元素分析结果的确证.通过热重分析(TGA)得知,该类非结晶相的聚合物热分解温度较高,分别为371.7、386.6和391.8℃.所合成的聚合物固态时...通过Gilch反应合成了结构新颖、含四官能团单元的超支化PPV聚合物P1～P3.聚合物的结构得到1 H NMR和元素分析结果的确证.通过热重分析(TGA)得知,该类非结晶相的聚合物热分解温度较高,分别为371.7、386.6和391.8℃.所合成的聚合物固态时的紫外吸收及荧光发射相对于液态的紫外吸收及荧光发射,波长有明显的红移现象,并且该聚合物具有宽吸收、窄发射的特征,在电致发光器件和聚合物太阳能电池器件中将有潜在的应用前景.展开更多
基金This work was supported by the China Scholarship Council and the Grant-in-Aids for Scientific Research from Ministry of Education, Culture, Sports, Science and Technology, Japan.
文摘Novel shish-kebab type liquid crystalline poly（p-phenylenevinylene） derivatives were synthesized by Stille coupling reaction from 2,5-bis[（4-n-alkoxyl）benzoyloxy]1,4-dibromobenzene （monomer l） and 1,2-bis（tributylstannyl） ethylene （monomer 2）. The polymers with alkoxy groups are soluble in common organic solvents and exhibit blue fluorescence. Both the cast film and the annealed film have large red-shifts in fluorescence spectra and show yellow fluorescence. The polymers with CN and NO2 groups show poor solubility and green fluorescence. All the polymers possess liquid crystalline smectic phases. The melting point （Tm） of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The polymers are easily aligned under a magnetic field of 10 Tesla. It is found that the conjugated backbone and LC side chain are aligned perpendicular and parallel to the magnetic field, respectively. The polymers show optical dichroism in fluorescence spectra, suggesting that they are available for advance materials with linear optical polarization.
基金Project suplorted b＇y the National Natural Science Foundation of China （Nos. 50773049, 20974075） and the Program of Innovative Research Team of Soochow University and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘A series of poly（p-phenylenevinylene）s （PPVs） with good solubility were synthesized from thermal elimination of precursor poly（2,5-didodecyloxy-p-phenylenevinylene） at different temperature via Wessling method. The polymer photophysics were influenced by the thermal elimination condition, which was consistent with NMR and IR characterizations. The additional absorption peak at longer wavelength and the red-shifted emission maximum both in solution and in film, for PPVs obtained at high elimination temperature, indicated the existence of longer conjugated blocks in these systems. The emission maximum for drop-cast film （436 nm） for PPV obtained under 200 ℃ （PPV200） was 16 nm blue shifted to the spin-coated films （452 nm） or 29 nm to the solution （465 nm）. The SEM study showed drop-cast film had the morphology of isolated conjugated particles in the matrix while blurry linear structure was found for spin-coated film, which was consistent with the photophysics. The discussion about this difference was carried out based on the consideration of the flexibility of the polymer chains and different conjugated length of PPV in different states.
基金supported by the National Natural Science Foundation of China(Nos.20774043,20874048)the Fok Ying-Tong Education Foundation(No.111051)+1 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK2008453)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications (NUPT)(Nos.NY207035 and NY207011)
文摘A cationic poly(p-phenylene vinylene) related copolymer without bulky phenylene substitutents attached to the conjugated backbone was prepared through Wittig reaction.The molecular structure and optical properties were highly investigated through ~1H-NMR,UV and PL spectroscopy.The quenching behavior was also investigated,and the results demonstrate that incomplete quenching exists,which is consistent with the cationic poly(p-phenylene vinylene) related copolymer containing bulky phenylene substitutents,prob...
文摘Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing length of the flexible blocks. Bright blue-light emitting diodes were fabricated using PPV copolymers as electroluminescent layers. The devices show 190 cd/m2 light-emitting brightness at 460 nm and 15 V turn-on voltage. The effects of oxadiawle derivative PBD and tris(8-hydroxyquinoline) aluminum Alq3 electron-transporting layers on the luminance and stability of the devices are discussed.
文摘通过Gilch反应合成了结构新颖、含四官能团单元的超支化PPV聚合物P1～P3.聚合物的结构得到1 H NMR和元素分析结果的确证.通过热重分析(TGA)得知,该类非结晶相的聚合物热分解温度较高,分别为371.7、386.6和391.8℃.所合成的聚合物固态时的紫外吸收及荧光发射相对于液态的紫外吸收及荧光发射,波长有明显的红移现象,并且该聚合物具有宽吸收、窄发射的特征,在电致发光器件和聚合物太阳能电池器件中将有潜在的应用前景.
