The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness o...The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness of lamellae is about 300A, being independent of the crystalline temperature. But the size and density of lamellae were dependent on the crystallization temperature. If the molten film was sheared during the crystallzation process the oriented lamellae grew with their long axes perpendicular to the direction of shear and the chain direction was normal to the lamellar surface.展开更多
To understand and control the interfacial properties of polydiacetylenes(PDAs)vesicles withπ-conjugated backbone is very important for their colorimetric sensing of chemical and biological targets.In this work,we ado...To understand and control the interfacial properties of polydiacetylenes(PDAs)vesicles withπ-conjugated backbone is very important for their colorimetric sensing of chemical and biological targets.In this work,we adopted 10,12-pentacosadiynoic acid(PCDA)as the model molecule to prepare PDAs vesicles in aqueous solution with different forms(from monomer to blue-to-purple-to-red phase)by controlling the UV irradiation dose.The variations of the interfacial conformation of PDAs vesicles during chromatic transitions were inspected by the adsorption behaviors of probe molecules(4-(4-diethylaminostyry)-1-methylpyridinium iodide,D289)on vesicle surface with surface-specific second harmonic generation(SHG)and zeta potential measurements.Resonant SHG signal from D289 adsorbed on vesicle surface attenuated sharply,and the adsorption free energy as well as the corresponding two-photon fluorescence signal decreased slightly in chromatic transitions.While,the change in the surface density of the adsorbed D289 molecules for PDAs vesicles with different forms was relatively small as estimated from zeta potential measurements.The attenuation of the SHG intensity was thus attributed to the overall order-disorder transition and the changed orientation of D289 molecules caused by the gradual distortion of carboxyl head group driven by backbone perturbation.展开更多
The thermotropic liquid crystalline behavior of a fusible polydiacetylene has been studied by using polarizing optical microscopy and wide angle X-ray diffraction. It was found that the typical threaded texture can ex...The thermotropic liquid crystalline behavior of a fusible polydiacetylene has been studied by using polarizing optical microscopy and wide angle X-ray diffraction. It was found that the typical threaded texture can exhibit in the melt and the banded texture can be observed when applied a gentle shear to the melt. The results indicate that this polydiacetylene is really a thermotropic liquid crystalline polymer.展开更多
We have synthesized and characterized two different nanoassemblies of polydiacetylene (PDA), PDA nanovesicles and PDA nanocrystals, in order to study the influence of chain packing geometry of the two nanoassemblies o...We have synthesized and characterized two different nanoassemblies of polydiacetylene (PDA), PDA nanovesicles and PDA nanocrystals, in order to study the influence of chain packing geometry of the two nanoassemblies on their third order nonlinear optical properties. The second molecular hyperpolarizability γ(-ω,ω,-ω,ω)of the two samples was investigated by antiresonant ring interferometric nonlinear spectroscopic (ARINS) technique using femtosecond modelocked Ti:sapphire laser in the spectral range of 720 nm - 820 nm. The observed spectral dispersion of γ has been explained in the framework of three-essential states model involving the ground state, a one-photon excited state and a two-photon excited state. The observed optical nonlinearity has been correlated with the electronic structure of the two samples. The energy of two-photon state, transition dipole moments and line width of the transitions have been estimated. Our studies show that the arrangement of polymer chains in polydiacetylene nanocrystals is more favorable for higher nonlinearity.展开更多
本文采用LCAO_SCF ab initio晶体轨道方法计算了聚丁二炔的两种可能结构:乙炔型结构CR—C≡C—CR′和丁三烯型结构∈_nCR=C=CR′的能量和能带结构;讨论了不同侧链基团聚丁二炔的两种结构的能量稳定性及其能带结构的变化;并从侧链基团的...本文采用LCAO_SCF ab initio晶体轨道方法计算了聚丁二炔的两种可能结构:乙炔型结构CR—C≡C—CR′和丁三烯型结构∈_nCR=C=CR′的能量和能带结构;讨论了不同侧链基团聚丁二炔的两种结构的能量稳定性及其能带结构的变化;并从侧链基团的性质及这两种结构的差别进行了分析,较好地解释了计算结果。展开更多
文摘The crystalline behavior of urethane substitute polydiacetylene was studied by using pohrized light and electron microscopy. The lamellar morphological structure was observed in the crystallized films. The thickness of lamellae is about 300A, being independent of the crystalline temperature. But the size and density of lamellae were dependent on the crystallization temperature. If the molten film was sheared during the crystallzation process the oriented lamellae grew with their long axes perpendicular to the direction of shear and the chain direction was normal to the lamellar surface.
基金This work was supported by the National Natural Science Foundation of China(No.21403292,No.21403293,No.21473249,and No.21673285),and the funding from the Shenzhen city(No.JCYJ20170307150520453).
文摘To understand and control the interfacial properties of polydiacetylenes(PDAs)vesicles withπ-conjugated backbone is very important for their colorimetric sensing of chemical and biological targets.In this work,we adopted 10,12-pentacosadiynoic acid(PCDA)as the model molecule to prepare PDAs vesicles in aqueous solution with different forms(from monomer to blue-to-purple-to-red phase)by controlling the UV irradiation dose.The variations of the interfacial conformation of PDAs vesicles during chromatic transitions were inspected by the adsorption behaviors of probe molecules(4-(4-diethylaminostyry)-1-methylpyridinium iodide,D289)on vesicle surface with surface-specific second harmonic generation(SHG)and zeta potential measurements.Resonant SHG signal from D289 adsorbed on vesicle surface attenuated sharply,and the adsorption free energy as well as the corresponding two-photon fluorescence signal decreased slightly in chromatic transitions.While,the change in the surface density of the adsorbed D289 molecules for PDAs vesicles with different forms was relatively small as estimated from zeta potential measurements.The attenuation of the SHG intensity was thus attributed to the overall order-disorder transition and the changed orientation of D289 molecules caused by the gradual distortion of carboxyl head group driven by backbone perturbation.
基金This work was supported by the National Basic Research Project-Macromolecular Condensed State
文摘The thermotropic liquid crystalline behavior of a fusible polydiacetylene has been studied by using polarizing optical microscopy and wide angle X-ray diffraction. It was found that the typical threaded texture can exhibit in the melt and the banded texture can be observed when applied a gentle shear to the melt. The results indicate that this polydiacetylene is really a thermotropic liquid crystalline polymer.
文摘We have synthesized and characterized two different nanoassemblies of polydiacetylene (PDA), PDA nanovesicles and PDA nanocrystals, in order to study the influence of chain packing geometry of the two nanoassemblies on their third order nonlinear optical properties. The second molecular hyperpolarizability γ(-ω,ω,-ω,ω)of the two samples was investigated by antiresonant ring interferometric nonlinear spectroscopic (ARINS) technique using femtosecond modelocked Ti:sapphire laser in the spectral range of 720 nm - 820 nm. The observed spectral dispersion of γ has been explained in the framework of three-essential states model involving the ground state, a one-photon excited state and a two-photon excited state. The observed optical nonlinearity has been correlated with the electronic structure of the two samples. The energy of two-photon state, transition dipole moments and line width of the transitions have been estimated. Our studies show that the arrangement of polymer chains in polydiacetylene nanocrystals is more favorable for higher nonlinearity.
文摘本文采用LCAO_SCF ab initio晶体轨道方法计算了聚丁二炔的两种可能结构:乙炔型结构CR—C≡C—CR′和丁三烯型结构∈_nCR=C=CR′的能量和能带结构;讨论了不同侧链基团聚丁二炔的两种结构的能量稳定性及其能带结构的变化;并从侧链基团的性质及这两种结构的差别进行了分析,较好地解释了计算结果。
