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
We report a facile approach to water-dispersible polydiacetylene/rare earth ions nanocomposites with reversible thermochromism. The nanocomposites were prepared by doping rare earth ions Dy^3＋ or Sin^3＋ into layer-s...We report a facile approach to water-dispersible polydiacetylene/rare earth ions nanocomposites with reversible thermochromism. The nanocomposites were prepared by doping rare earth ions Dy^3＋ or Sin^3＋ into layer-structured 10,12-pentacosadiynoic acid （PCDA） nanopar- ticles to obtain PCDA/rare earth ions nanocomposites （PCDA-RE） and subsequently annealing PCDA-RE at the temperature slightly higher than the melting point of pure PCDA crystals, followed by topochemically polymerizing the annealed PCDA-RE. The polymerized PCDA-RE, i.e. poly（10,12-pentacosadiynoic acid）/rare earth ions nanocomposites （PDARE： PDA-Dy or PDA-Sm）, are largely reversible （PDA-Sm） or even completely reversible （PDA-Dy） in the thermochromism, while, without the doping, pure PDA is completely irreversible. It is confirmed that, PDA-RE are also layer-structured with a d-spacing of 5.4 nm, higher than the d-spacing of pure PDA （4.7 nm）. In PDA-RE, the rare earth ions form a layer in-between and interact strongly with the PDA bilayers, being responsible for the high degree or even the complete reversibility. This is the first example to make PDA completely reversible through the doping of rare earth ions; the annealing process is essential for the complete reversibility since it removes any defects in the structure.展开更多
Polydiacetylene(PDA)is one kind of the conjugated polymer with layered structure,which can serve as a host to accommodate the guest components through intercalation.In these intercalated PDAs,some of them were reporte...Polydiacetylene(PDA)is one kind of the conjugated polymer with layered structure,which can serve as a host to accommodate the guest components through intercalation.In these intercalated PDAs,some of them were reported to have a nearly perfect organized structure and perform completely reversible thermochromism.Till now,these reported intercalated PDAs were made by only introducing a single component for intercalation.Here,we chose 10,12-pentacosadiynoic acid(PCDA)as the monomer,of which the carboxyl-terminal groups can interact with either Tb^3+ ions or melamines(MAs).When the feeding molar ratio of PCDA,MA,and Tb^3+ ion was 3:267:1,only Tb^3+ ions were intercalated though excess MAs existed.Such Tb^3+- intercalated poly-PCDA exhibited completely reversible thermochromism,where almost all the carboxyl groups interacted with Tb^3+ ions to form the nearly perfect structure.When the feeding molar ratio of PCDA,MA,and Tb^3+ ion was 3:267:0.6,both Tb^3+ ions and MAs were intercalated.There existed some defects in the imperfect MA-intercalated domains and at the domain boundaries.The MA/Tb^3+- intercalated poly-PCDA exhibits partially reversible thermochromism,where the backbones near the defects are hard to return the initial conformation,while the rest,those at nearly perfect organized domains,are still able to restore the initial conformation.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
We demonstrate a very convenient access to self-suspended pure poly（10,12-pentacosadiynoic acid） （PDA） nanoparticles （NPs） simply by adding the ethanol solution of diacetylene monomer to water, followed by UV ir...We demonstrate a very convenient access to self-suspended pure poly（10,12-pentacosadiynoic acid） （PDA） nanoparticles （NPs） simply by adding the ethanol solution of diacetylene monomer to water, followed by UV irradiation. The as-obtained PDA NPs are of high purity because no any initiator, catalyst or stabilizer was used during the whole process. The stabilizer-free PDA NPs are stable in the aqueous suspension. Due to the high purity and stability, the PDA NPs can respond sensitively and selectively to lysine and arginine among 18 kinds of water soluble natural amino acids; without the competitive interaction from the stabilizer, the sensitivity was enhanced.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
The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(PDA)materials have always been a challenging issue.In this work,a series of diacetylene monomers(...The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(PDA)materials have always been a challenging issue.In this work,a series of diacetylene monomers(m-PCDA)containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid(PCDA)through the esterification or amidation reactions.The effects of the number and the distribution of the functional groups in m-PCDA molecules on their solid-state polymerization capability,and the thermochromic mechanism of their corresponding polymers(m-PDA)were investigated and discussed in detail.The results show that the m-PCDA monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction,and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-PDA materials.The thermochromic behavior of m-PDA depends on its melting process.The initial color-change temperature(blue to red)is determined by the onset melting tem perature,and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting range.According to the proposed thermochromic mechanism of PDA,various new PDA materials with precise thermochromic temperatu res and reversible thermochromic temperature ra nges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene monomer.This work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic PDA materials.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V.ACKNOWLEDGEMENTSThisworkwassupportedbytheNationalNatu-ralScienceFoundationofChina（No.21334001andNo.91127030）.V. ACKNOWLEDGEMENTS This work was supported by the National Natu- ral Science Foundation of China （No.21334001 and No.91127030）.
文摘We report a facile approach to water-dispersible polydiacetylene/rare earth ions nanocomposites with reversible thermochromism. The nanocomposites were prepared by doping rare earth ions Dy^3＋ or Sin^3＋ into layer-structured 10,12-pentacosadiynoic acid （PCDA） nanopar- ticles to obtain PCDA/rare earth ions nanocomposites （PCDA-RE） and subsequently annealing PCDA-RE at the temperature slightly higher than the melting point of pure PCDA crystals, followed by topochemically polymerizing the annealed PCDA-RE. The polymerized PCDA-RE, i.e. poly（10,12-pentacosadiynoic acid）/rare earth ions nanocomposites （PDARE： PDA-Dy or PDA-Sm）, are largely reversible （PDA-Sm） or even completely reversible （PDA-Dy） in the thermochromism, while, without the doping, pure PDA is completely irreversible. It is confirmed that, PDA-RE are also layer-structured with a d-spacing of 5.4 nm, higher than the d-spacing of pure PDA （4.7 nm）. In PDA-RE, the rare earth ions form a layer in-between and interact strongly with the PDA bilayers, being responsible for the high degree or even the complete reversibility. This is the first example to make PDA completely reversible through the doping of rare earth ions; the annealing process is essential for the complete reversibility since it removes any defects in the structure.
基金supported by the Programs of the Shanghai Pujiang Program(No.18PJ1401500)the National Natural Science Foundation of China(No.21801046,No.51721002,No.21574025 and No.21871057)the Ministry of Science and Technology(2016YFA0203302)。
文摘Polydiacetylene(PDA)is one kind of the conjugated polymer with layered structure,which can serve as a host to accommodate the guest components through intercalation.In these intercalated PDAs,some of them were reported to have a nearly perfect organized structure and perform completely reversible thermochromism.Till now,these reported intercalated PDAs were made by only introducing a single component for intercalation.Here,we chose 10,12-pentacosadiynoic acid(PCDA)as the monomer,of which the carboxyl-terminal groups can interact with either Tb^3+ ions or melamines(MAs).When the feeding molar ratio of PCDA,MA,and Tb^3+ ion was 3:267:1,only Tb^3+ ions were intercalated though excess MAs existed.Such Tb^3+- intercalated poly-PCDA exhibited completely reversible thermochromism,where almost all the carboxyl groups interacted with Tb^3+ ions to form the nearly perfect structure.When the feeding molar ratio of PCDA,MA,and Tb^3+ ion was 3:267:0.6,both Tb^3+ ions and MAs were intercalated.There existed some defects in the imperfect MA-intercalated domains and at the domain boundaries.The MA/Tb^3+- intercalated poly-PCDA exhibits partially reversible thermochromism,where the backbones near the defects are hard to return the initial conformation,while the rest,those at nearly perfect organized domains,are still able to restore the initial conformation.
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.
文摘We demonstrate a very convenient access to self-suspended pure poly（10,12-pentacosadiynoic acid） （PDA） nanoparticles （NPs） simply by adding the ethanol solution of diacetylene monomer to water, followed by UV irradiation. The as-obtained PDA NPs are of high purity because no any initiator, catalyst or stabilizer was used during the whole process. The stabilizer-free PDA NPs are stable in the aqueous suspension. Due to the high purity and stability, the PDA NPs can respond sensitively and selectively to lysine and arginine among 18 kinds of water soluble natural amino acids; without the competitive interaction from the stabilizer, the sensitivity was enhanced.
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.
基金financially supported by the National Natural Science Foundation of China(No.51973205)the Fundamental Research Funds for the Central Universities(Nos.WK9110000066,WK3450000005 and WK3450000006)。
文摘The thermochromic mechanism and the structure-property regulation principle of reversible thermochromic polydiacetylene(PDA)materials have always been a challenging issue.In this work,a series of diacetylene monomers(m-PCDA)containing phenyl and amide or carboxyl groups were synthesized from 10,12-pentacosadiynoic acid(PCDA)through the esterification or amidation reactions.The effects of the number and the distribution of the functional groups in m-PCDA molecules on their solid-state polymerization capability,and the thermochromic mechanism of their corresponding polymers(m-PDA)were investigated and discussed in detail.The results show that the m-PCDA monomers containing both benzene ring and groups that can form hydrogen bonding interactions have strong intermolecular interaction,and are easy to carry out the solid phase polymerization under 254-nm UV irradiation to obtain the corresponding new thermochromic m-PDA materials.The thermochromic behavior of m-PDA depends on its melting process.The initial color-change temperature(blue to red)is determined by the onset melting tem perature,and the temperature range in which reversible color recovery can be achieved by repeat heating-cooling treatment is determined by its melting range.According to the proposed thermochromic mechanism of PDA,various new PDA materials with precise thermochromic temperatu res and reversible thermochromic temperature ra nges can be designed and synthesized through the appropriate introduction of benzene ring and groups that can form hydrogen bonding interactions into the molecular structure of linear diacetylene monomer.This work provides a perspective to the precise molecular structure design and the property regulation of the reversible thermochromic PDA materials.
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。
