Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, p...Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, polymeric amines, such as polyethyleneimine, show some disadvantages. Strong interaction between the amine-containing polymer and nucleic acid hampers the release of nucleic acid in the cell cytoplasm. Amine groups can interact with the cell membrane which results in cell death. These limitations of polymeric amines stimulated an investigation of new structures for gene delivery. Imidazole-containing polymers have attracted attention as lesser basic substances, while they are able to interact with polymeric acids. Further development of imidazole-based gene delivery agents requires knowledge about some fundamental aspects of interaction between nucleic acids, and polymeric imidazoles. In this work, we studied the complexation of poly(1-vinylimidazole) and oligomeric DNA. We found that the number of active sites capable of binding with negatively charged phosphate groups is comparable with the number of protonated imidazole units in the case of high molecular weight polymer. The increase in polymer charge by 1-bromopropane quaternizating 1%?5% imidazole units or by decreasing the pH to 6.5?7 considerably increased the ability of poly(1-vinylimidazole) to interact with oligonucleotides. The pH sensitivity of this interaction is interesting for cancer gene therapy because the tumours have a lowered intercellular pH (stable oligonucleotide complex) and a higher extracellular pH which can lead to complex dissociation. Minimal critical length for complexation of quaternized poly(1-vinylimidazole) and DNA is below eight units which corresponds to polymers with amine groups. Fluorescence-tagged poly(1-vinylimidazole) samples were obtained and their potential for monitoring the polymer and polymer-oligonucleotide complex internalization into living cells was demonstrated.展开更多
While WCl_6-Ph_4Sn fails to polymerize 1-phenyl-1-propyne (PP) at room temperature, highmolecular weight (M_w up to 410× 10~3) polymers are obtained in high yields (up to 80%) when thepolymerizations of PP are ca...While WCl_6-Ph_4Sn fails to polymerize 1-phenyl-1-propyne (PP) at room temperature, highmolecular weight (M_w up to 410× 10~3) polymers are obtained in high yields (up to 80%) when thepolymerizations of PP are carried out in the presence of C_(60) using the W catalyst under the same conditions.The polymers are soluble in common organic solvents such as THF, chloroform, and toluene. Molecularstructures of the polymers are characterized by FT-IR, UV, NMR, GPC and XRD, and it is found that C_(60) iscopolymerized with PP. Thus C_(60) plays the dual roles of comonomer and cocatalyst in the polymerizationreaction. C_(60) contents of the copolymers can be easily changed by varying the C_(60) amounts in the feedmixtures. The copolymers effectively limit strong 532 nm laser pulses, whose limiting performance issuperior to that of parent C_(60).展开更多
FTIR, UV-visible , fluorescence spectra and calculation of CPK model indicated that poly(1-naphthol) synthesized and assembled by horseradish peroxidase(HRP) in aqueous micelle was constructed with orderly helical co...FTIR, UV-visible , fluorescence spectra and calculation of CPK model indicated that poly(1-naphthol) synthesized and assembled by horseradish peroxidase(HRP) in aqueous micelle was constructed with orderly helical conformation, which was the lowest energy conformation of the polymer under this condition and resulted in an advanced c-conjugated system.展开更多
Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechan...Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechanism. When compared to the crystal thickness (d(c)), the volume occupied by the chain in the melts i.e., the radius of gyration (R-g), plays a very important role in polymer crystallization. When d(c) less than or equal to R-g, crystallization does not necessitate a chain disentangling. The entanglements are just shifted into the amorphous regions. However, as d(c)>R-g, i.e., as the crystal thickness gets larger than the radius of gyration of the chain in the melt, it becomes necessary for a chain to disentangle. Then a change of crystallization mechanism occurs. Such change has been experimentally observed in the crystallization of poly(I-butene). A change in the crystal morphologies from spherulite to quadrangle, is seen via PLM, as crystallization temperatures increase. Even more, such a change is molecular weight dependent, and shifts to lower temperature as molecular weight decreases. There exists a jump of crystal thickness and crystallinity associated with morphological change, as seen via SAXS. A change of crystallization kinetics and crystallinity is further evidenced via dilatometry. The unique feature of P1b crystallization has been discussed based on the radius of gyration of chain in the melt (R-g), and very good agreement is obtained.展开更多
Zinc ions (Zn2+), known to be a novel intracellular second messenger related to various biological functions, have been delivered inside cells. For the intracellular Zn2+ delivery, Zn2+ has been chelated to carboxymet...Zinc ions (Zn2+), known to be a novel intracellular second messenger related to various biological functions, have been delivered inside cells. For the intracellular Zn2+ delivery, Zn2+ has been chelated to carboxymethyl poly(1-vinylimidazole) (CM-PVIm) by mixing zinc chloride (ZnCl2) or zinc acetate (Zn(OAc)2) with CM-PVIm. The resulting Zn2+-chelated CM-PVIm, that is, Zn2+/CM-PVIm complex by mixing ZnCl2 exhibited smaller particle size below 10 nm and possessed larger amount of Zn2+ ions, as compared to the Zn2+/CM-PVIm by mixing Zn(OAc)2. The both Zn2+/CM-PVIm complexes exhibited no significant cytotoxicity, leading to intracellular Zn2+ delivery. The Zn2+/CM-PVIm by mixing ZnCl2 delivered larger amount of intracellular Zn2+ ions than that by mixing Zn(OAc)2. These results suggest that the optimal Zn2+/CM-PVIm complex is a useful tool for intracellular Zn2+ delivery to control various biological functions.展开更多
In this study, the conjugated polymer, poly(1-methoxy-4-octyloxy)-para-phenylene vinylene (MO-p-PPV) was synthesized and characterized. MO-p-PPV was synthesized according to Gilch polymerization mechanism by using 4-m...In this study, the conjugated polymer, poly(1-methoxy-4-octyloxy)-para-phenylene vinylene (MO-p-PPV) was synthesized and characterized. MO-p-PPV was synthesized according to Gilch polymerization mechanism by using 4-methoxyphenol as starting material in the presence of potassium tert-butoxide (1M in THF). The product was further purified by multiple precipitations in different solvents such as methanol, tetrahydrofuran, isopropyl alcohol and hexane. The final product was dried to afford MO-p-PPV as a red solid. The resulting polymer was completely soluble in common organic solvents. The structure of monomer and optical properties of polymer were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, UV-vis spectroscopy, and fluorescence spectroscopy. The UV-vis spectrum showed absorption maxima for MO-p-PPV at 491 nm. Similarly, fluorescence spectrum showed λmax emission at 540 nm.展开更多
Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract h...Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract heptamolybdate ion(Mo7O246−)and Sn^(4+)as the precursors by the ion‐exchange,resulting in the simultaneous growth of 1T’‐MoS2 and the berndtite‐2T‐type hexagonal SnS_(2)by the interfacial induced effect of PVIPS.The obtained MoS_(2)‐SnS_(2)/PVIPS/PPy/GO can serve as electrocatalysts,exhibiting good NRR performance by the synergistic effect.The semi‐conducting SnS_(2)would limit the surface electron accessibility for suppressing HER process of 1T’‐MoS_(2),while metallic 1T’‐MoS_(2)might efficiently improve the NRR electroactivity of SnS_(2)by the creation of Mo‐Sn‐Sn trimer catalytic sites.Otherwise,the irreversible crystal phase transition has taken place during the NRR process.Partial 1T’‐MoS_(2)and SnS_(2)have electrochemically reacted with N_(2),and irreversibly converted into Mo^(2)N and SnxNz due to the formation of Mo−N and Sn−N bonding,meanwhile,partial SnS_(2) has been irreversibly evolved into SnS due to the reduction by the power source in the electrochemical system.It would put forward a new design idea for optimizing the preparation method and electrocatalytic activity of transition metal dichalcogenides.展开更多
The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which...The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.展开更多
To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synth...To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synthesized by RuCl3 catalyzed redox reaction of meso-5,10,15,20-tetra(4-nitrophenyl)porphyrin cobalt(TNO2PorCo)and 1,4-phenyldimethanol.M-PImPorCo is a fully conjugated covalent organic framework(COF)with high thermal and chemical stability.COFs with different edge groups were synthesized to compare the effect of different groups(–CH_(2)–OH and–NO_(2))on catalytic bifunctional oxygen reaction activity.C=N as nitrogen-rich environment of M-PImPorCo leads to the protonation process of oxygen catalysis and reduces the energy barrier of adsorption in the oxygen intermediate.C=N and–CH_(2)–OH form an“electron pump”structure to deliver electrons to the Co–N4 site in M-PImPorCo,and theπ–πinteraction between M-PImPorCo and three-dimensional graphene(3D-G)can further enrich the electron cloud density of Co–N4 sites.M-PImPorCo/3D-G has remarkable oxygen catalytic performance,with a half-wave potential(E_(1/2))of 0.91 V vs.reversible hydrogen electrode(RHE).M-PImPorCo/3D-G has low potential(Ej=10 is 1.49 V vs.RHE)at a current density of 10 mA·cm^(-2).It exhibits a good bifunctional catalytic performance(potential difference(ΔE)=0.58 V).The smaller charge–discharge band gap of zinc-air batteries(ZABs)and flexible ZABs(F-ZABs)equipped with M-PImPorCo/3D-G suggests the potential for catalytic oxygen reaction bifunctional applications.This work provides a new idea for the synthesis of Schiff-base porphyrin-based COF catalyst and its potential application to oxygen reaction catalytic energy storage devices.展开更多
Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical applicatio...Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical application is hindered by the high reactivity of sodium metal,interfacial and structural instability,and fire safety risks.Herein,a poly(1,3-dioxolane)(PDOL)crosslinked quasi-solid-state electrolyte(TPQSE)with fire extinguishing property and superior interface compatibility with sodium(Na)anodes and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes is prepared via in situ polymerization at room temperature(RT),utilizing trimethylolpropane triglycidyl ether(TTE)as a crosslinker in coordination with ethoxy(pentafluoro)cyclotriphosphazene(PFPN).The crosslinked network of TPQSE and the distinct solvation properties of TPDOL and PFPN facilitate Na-ion desolvation while enhancing antioxidant stability of TPQSE.Moreover,multifunctional PFPN improves fire safety through condensed-phase dense char layer formation and gas-phase free radical capturing.It also constructs uniform,dense,and inorganic-rich interphases between electrodes and electrolytes,strengthening interfacial stability.Consequently,the prepared electrolyte exhibits high ionic conductivity(2.109 mS cm^(-1)at RT),high Na^(+)transference number(0.570),and extended electrochemical window to 4.805 V.The Na‖TPQSE‖Na symmetric cell presents impressive cycling stability over 4510 h,and the Na‖TPQSE‖NVP cell displays outstanding rate capability and stable long-term cycling(≥2300 cycles).This work provides a promising approach for developing safe and high-performance quasi-solid-state sodium metal batteries.展开更多
Stereospecific polymerization of polar olefins has always been an attractive but challenging project because the Lewis basic polar groups of monomers are usually poisonous to the Lewis acidic metal centers of the cata...Stereospecific polymerization of polar olefins has always been an attractive but challenging project because the Lewis basic polar groups of monomers are usually poisonous to the Lewis acidic metal centers of the catalysts. In this contribution,thiophene-fused cyclopentadienyl scandium complexes 1-3 were successfully synthesized. Combined with alkylaluminium and organoborate, these complexes showed extremely low activity and no selectivity for 1-hexene polymerization. Surprisingly,highly stereo-selective coordination polymerization of unprotected polar 4-methylthio-1-butene has been achieved in high activity for the first time under the same polymerization conditions. High-molecular-weight(M_n=110×10~3) and perfectly syndiotactic(rrrr>99%) poly(4-methylthio-1-butene)(P(MTB)) was afforded. Thus the methylthio-group-assisted mechanism that the unmasked methylthio group promoted the polymerization through σ-π chelation to the active scandium center together with the vinyl group was proposed. Moreover, the methylsulfonyl functionalized syndiotactic poly(1-butene) was also easily prepared by the oxidation of P(MTB). These results provided a new route for the synthesis of functionalized stereo-regular polyolefins.展开更多
An organic macromolecule, poly(1-vinylimidazole), with an appropriate polymerization degree was proposed and mixed with water to form a novel aqueous absorbent for SO_2 capture. This aqueous solution absorbent has the...An organic macromolecule, poly(1-vinylimidazole), with an appropriate polymerization degree was proposed and mixed with water to form a novel aqueous absorbent for SO_2 capture. This aqueous solution absorbent has the advantages of simple preparation, good physicochemical properties, environment-friendliness, high ability in deep removal of SO_2, and excellent reusability. Moreover, pH-responsive behavior, pH buffering absorption mechanism, and their synergistic effect on absorption performance were revealed. The solubilities of SO_2 in the absorbent were measured in detail, and the results demonstrated excellent absorption capacity and recyclability. Then, mathematic models that describe SO_2 absorption equilibrium were established, and the corresponding parameters were estimated. More importantly, on the basis of model and experimental data, the absorption and desorption could maintain high efficiency within a wide operating region. In summary, this work provided a low-cost, efficient, and unique absorbent for SO_2 capture and verified its technical feasibility in industrial application.展开更多
OBJECTIVE To formulate atractylodin-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles and characterize the prepared nanoparticle formulation.METHODS The nanoparticle formulation was developed using solvent displ...OBJECTIVE To formulate atractylodin-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles and characterize the prepared nanoparticle formulation.METHODS The nanoparticle formulation was developed using solvent displacement method.The encapsulation and loading efficiency were characterized and particle size,and zeta potential were determined by dynamic light scattering technique.Drug release was assessed in vitro.RESULTS The size(mean±SD of diameter) of the prepared atractylodin-loaded PLGA nanoparticles were(161.27 ± 1.87)nm with narrow size distribution(mean PDI:0.068±0.015) and zeta potential(28.83±0.35)mV.The encapsulation and loading efficiency were(48.31±0.83)% and(2.15±0.04)%,respectively.Drug release from atractylodin-loaded PLGA nanoparticles was observed up to(87.70±0.47)% in 72 h with biphasic manner.Moreover,the nanoparticles were found to be freely dispersible in water without aggregation.CONCLUSION Results suggest that PLGA nanoparticles may be used as an effective drug delivery system for atractylodin.The anti-cholangiocarcinoma activity of this nanoparticle formulation is required.展开更多
Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of h...Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of high purity s-SWCNTs.However,its chiral selectivity is relatively inferior to other s-SWCNT production methods.In this paper,the chiral selectivity of two polymers,poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(6,6′-{2,2′-bipyridine})](PFO-BPy)and poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl](PCz),which are representatives of widely used polyfluorene and polycarbazole families,respectively,were comparatively studied.Both polymers exhibited high selectivity for a subset of existing chiral species in each of the commercially available raw SWCNT materials(CoMoCAT,HiPco,and arc-discharge)which cover a diameter range of 0.6–1.8 nm.Less chiral species were selected by PFO-BPy from small diameter(<1 nm)raw SWCNT materials,while more from large diameter(>1.2 nm)raw materials.High chiral purity(6,5)(>99%)and(7,5)(>75%)solutions were extracted by PFO-BPy and PCz from CoMoCAT materials,respectively.The different chiral angle and diameter selections for different raw materials by both polymers were ascribed to their different geometrical structures and related polymer-tube interactions.Our work provides indispensable information for better understanding the mechanism of polymer wrapping method and improving extraction of single chirality sSWCNTs.展开更多
基金financial support from a joint grant of the Russian Science Foundation (16-45-02001)the Department of Science Technology of the Ministry of Science and Technology of the Republic of India (INT/RUS/RSF/10)
文摘Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, polymeric amines, such as polyethyleneimine, show some disadvantages. Strong interaction between the amine-containing polymer and nucleic acid hampers the release of nucleic acid in the cell cytoplasm. Amine groups can interact with the cell membrane which results in cell death. These limitations of polymeric amines stimulated an investigation of new structures for gene delivery. Imidazole-containing polymers have attracted attention as lesser basic substances, while they are able to interact with polymeric acids. Further development of imidazole-based gene delivery agents requires knowledge about some fundamental aspects of interaction between nucleic acids, and polymeric imidazoles. In this work, we studied the complexation of poly(1-vinylimidazole) and oligomeric DNA. We found that the number of active sites capable of binding with negatively charged phosphate groups is comparable with the number of protonated imidazole units in the case of high molecular weight polymer. The increase in polymer charge by 1-bromopropane quaternizating 1%?5% imidazole units or by decreasing the pH to 6.5?7 considerably increased the ability of poly(1-vinylimidazole) to interact with oligonucleotides. The pH sensitivity of this interaction is interesting for cancer gene therapy because the tumours have a lowered intercellular pH (stable oligonucleotide complex) and a higher extracellular pH which can lead to complex dissociation. Minimal critical length for complexation of quaternized poly(1-vinylimidazole) and DNA is below eight units which corresponds to polymers with amine groups. Fluorescence-tagged poly(1-vinylimidazole) samples were obtained and their potential for monitoring the polymer and polymer-oligonucleotide complex internalization into living cells was demonstrated.
基金This work was in part supported by the Hong Kong Research Grants Council(HKUST6062/98P and DAG96/97 SC11).
文摘While WCl_6-Ph_4Sn fails to polymerize 1-phenyl-1-propyne (PP) at room temperature, highmolecular weight (M_w up to 410× 10~3) polymers are obtained in high yields (up to 80%) when thepolymerizations of PP are carried out in the presence of C_(60) using the W catalyst under the same conditions.The polymers are soluble in common organic solvents such as THF, chloroform, and toluene. Molecularstructures of the polymers are characterized by FT-IR, UV, NMR, GPC and XRD, and it is found that C_(60) iscopolymerized with PP. Thus C_(60) plays the dual roles of comonomer and cocatalyst in the polymerizationreaction. C_(60) contents of the copolymers can be easily changed by varying the C_(60) amounts in the feedmixtures. The copolymers effectively limit strong 532 nm laser pulses, whose limiting performance issuperior to that of parent C_(60).
文摘FTIR, UV-visible , fluorescence spectra and calculation of CPK model indicated that poly(1-naphthol) synthesized and assembled by horseradish peroxidase(HRP) in aqueous micelle was constructed with orderly helical conformation, which was the lowest energy conformation of the polymer under this condition and resulted in an advanced c-conjugated system.
基金This work was supported by the Deutsche Forschungsgemeinschall and der Chemischen Industrierate, Alexander von Humboldt Stiffeng and the China National Distinguished Young Investigator Fund (No. 29925413).
文摘Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechanism. When compared to the crystal thickness (d(c)), the volume occupied by the chain in the melts i.e., the radius of gyration (R-g), plays a very important role in polymer crystallization. When d(c) less than or equal to R-g, crystallization does not necessitate a chain disentangling. The entanglements are just shifted into the amorphous regions. However, as d(c)>R-g, i.e., as the crystal thickness gets larger than the radius of gyration of the chain in the melt, it becomes necessary for a chain to disentangle. Then a change of crystallization mechanism occurs. Such change has been experimentally observed in the crystallization of poly(I-butene). A change in the crystal morphologies from spherulite to quadrangle, is seen via PLM, as crystallization temperatures increase. Even more, such a change is molecular weight dependent, and shifts to lower temperature as molecular weight decreases. There exists a jump of crystal thickness and crystallinity associated with morphological change, as seen via SAXS. A change of crystallization kinetics and crystallinity is further evidenced via dilatometry. The unique feature of P1b crystallization has been discussed based on the radius of gyration of chain in the melt (R-g), and very good agreement is obtained.
文摘Zinc ions (Zn2+), known to be a novel intracellular second messenger related to various biological functions, have been delivered inside cells. For the intracellular Zn2+ delivery, Zn2+ has been chelated to carboxymethyl poly(1-vinylimidazole) (CM-PVIm) by mixing zinc chloride (ZnCl2) or zinc acetate (Zn(OAc)2) with CM-PVIm. The resulting Zn2+-chelated CM-PVIm, that is, Zn2+/CM-PVIm complex by mixing ZnCl2 exhibited smaller particle size below 10 nm and possessed larger amount of Zn2+ ions, as compared to the Zn2+/CM-PVIm by mixing Zn(OAc)2. The both Zn2+/CM-PVIm complexes exhibited no significant cytotoxicity, leading to intracellular Zn2+ delivery. The Zn2+/CM-PVIm by mixing ZnCl2 delivered larger amount of intracellular Zn2+ ions than that by mixing Zn(OAc)2. These results suggest that the optimal Zn2+/CM-PVIm complex is a useful tool for intracellular Zn2+ delivery to control various biological functions.
文摘In this study, the conjugated polymer, poly(1-methoxy-4-octyloxy)-para-phenylene vinylene (MO-p-PPV) was synthesized and characterized. MO-p-PPV was synthesized according to Gilch polymerization mechanism by using 4-methoxyphenol as starting material in the presence of potassium tert-butoxide (1M in THF). The product was further purified by multiple precipitations in different solvents such as methanol, tetrahydrofuran, isopropyl alcohol and hexane. The final product was dried to afford MO-p-PPV as a red solid. The resulting polymer was completely soluble in common organic solvents. The structure of monomer and optical properties of polymer were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, UV-vis spectroscopy, and fluorescence spectroscopy. The UV-vis spectrum showed absorption maxima for MO-p-PPV at 491 nm. Similarly, fluorescence spectrum showed λmax emission at 540 nm.
文摘Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract heptamolybdate ion(Mo7O246−)and Sn^(4+)as the precursors by the ion‐exchange,resulting in the simultaneous growth of 1T’‐MoS2 and the berndtite‐2T‐type hexagonal SnS_(2)by the interfacial induced effect of PVIPS.The obtained MoS_(2)‐SnS_(2)/PVIPS/PPy/GO can serve as electrocatalysts,exhibiting good NRR performance by the synergistic effect.The semi‐conducting SnS_(2)would limit the surface electron accessibility for suppressing HER process of 1T’‐MoS_(2),while metallic 1T’‐MoS_(2)might efficiently improve the NRR electroactivity of SnS_(2)by the creation of Mo‐Sn‐Sn trimer catalytic sites.Otherwise,the irreversible crystal phase transition has taken place during the NRR process.Partial 1T’‐MoS_(2)and SnS_(2)have electrochemically reacted with N_(2),and irreversibly converted into Mo^(2)N and SnxNz due to the formation of Mo−N and Sn−N bonding,meanwhile,partial SnS_(2) has been irreversibly evolved into SnS due to the reduction by the power source in the electrochemical system.It would put forward a new design idea for optimizing the preparation method and electrocatalytic activity of transition metal dichalcogenides.
基金This work was supported by Academia Sinica selected Research Program and National Natural Science Foundation of China
文摘The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.
基金supported by the National Natural Science Foundation of China(Nos.22172093 and 21776167)the Natural Science Foundation of Shandong Province,China(No.ZR2023MB061).
文摘To solve the slow dynamics of catalytic oxygen reaction energy devices,a facile method was developed for the synthesis of methylene alcohol terminated poly(1,4-phenyldiimine)porphyrin cobalt(MPImPorCo),which was synthesized by RuCl3 catalyzed redox reaction of meso-5,10,15,20-tetra(4-nitrophenyl)porphyrin cobalt(TNO2PorCo)and 1,4-phenyldimethanol.M-PImPorCo is a fully conjugated covalent organic framework(COF)with high thermal and chemical stability.COFs with different edge groups were synthesized to compare the effect of different groups(–CH_(2)–OH and–NO_(2))on catalytic bifunctional oxygen reaction activity.C=N as nitrogen-rich environment of M-PImPorCo leads to the protonation process of oxygen catalysis and reduces the energy barrier of adsorption in the oxygen intermediate.C=N and–CH_(2)–OH form an“electron pump”structure to deliver electrons to the Co–N4 site in M-PImPorCo,and theπ–πinteraction between M-PImPorCo and three-dimensional graphene(3D-G)can further enrich the electron cloud density of Co–N4 sites.M-PImPorCo/3D-G has remarkable oxygen catalytic performance,with a half-wave potential(E_(1/2))of 0.91 V vs.reversible hydrogen electrode(RHE).M-PImPorCo/3D-G has low potential(Ej=10 is 1.49 V vs.RHE)at a current density of 10 mA·cm^(-2).It exhibits a good bifunctional catalytic performance(potential difference(ΔE)=0.58 V).The smaller charge–discharge band gap of zinc-air batteries(ZABs)and flexible ZABs(F-ZABs)equipped with M-PImPorCo/3D-G suggests the potential for catalytic oxygen reaction bifunctional applications.This work provides a new idea for the synthesis of Schiff-base porphyrin-based COF catalyst and its potential application to oxygen reaction catalytic energy storage devices.
基金the National Natural Science Foundation of China(52274232)the Fundamental Research Funds for the Central Universities(2024ZYGXZR016)。
文摘Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical application is hindered by the high reactivity of sodium metal,interfacial and structural instability,and fire safety risks.Herein,a poly(1,3-dioxolane)(PDOL)crosslinked quasi-solid-state electrolyte(TPQSE)with fire extinguishing property and superior interface compatibility with sodium(Na)anodes and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes is prepared via in situ polymerization at room temperature(RT),utilizing trimethylolpropane triglycidyl ether(TTE)as a crosslinker in coordination with ethoxy(pentafluoro)cyclotriphosphazene(PFPN).The crosslinked network of TPQSE and the distinct solvation properties of TPDOL and PFPN facilitate Na-ion desolvation while enhancing antioxidant stability of TPQSE.Moreover,multifunctional PFPN improves fire safety through condensed-phase dense char layer formation and gas-phase free radical capturing.It also constructs uniform,dense,and inorganic-rich interphases between electrodes and electrolytes,strengthening interfacial stability.Consequently,the prepared electrolyte exhibits high ionic conductivity(2.109 mS cm^(-1)at RT),high Na^(+)transference number(0.570),and extended electrochemical window to 4.805 V.The Na‖TPQSE‖Na symmetric cell presents impressive cycling stability over 4510 h,and the Na‖TPQSE‖NVP cell displays outstanding rate capability and stable long-term cycling(≥2300 cycles).This work provides a promising approach for developing safe and high-performance quasi-solid-state sodium metal batteries.
基金supported by the National Natural Science Foundation of China (21674108, 21634007, 21774118)the Science and Technology Development Project of Jilin Province (20190201067JC)
文摘Stereospecific polymerization of polar olefins has always been an attractive but challenging project because the Lewis basic polar groups of monomers are usually poisonous to the Lewis acidic metal centers of the catalysts. In this contribution,thiophene-fused cyclopentadienyl scandium complexes 1-3 were successfully synthesized. Combined with alkylaluminium and organoborate, these complexes showed extremely low activity and no selectivity for 1-hexene polymerization. Surprisingly,highly stereo-selective coordination polymerization of unprotected polar 4-methylthio-1-butene has been achieved in high activity for the first time under the same polymerization conditions. High-molecular-weight(M_n=110×10~3) and perfectly syndiotactic(rrrr>99%) poly(4-methylthio-1-butene)(P(MTB)) was afforded. Thus the methylthio-group-assisted mechanism that the unmasked methylthio group promoted the polymerization through σ-π chelation to the active scandium center together with the vinyl group was proposed. Moreover, the methylsulfonyl functionalized syndiotactic poly(1-butene) was also easily prepared by the oxidation of P(MTB). These results provided a new route for the synthesis of functionalized stereo-regular polyolefins.
基金supported by the National Key R&D Program of China (No. 2016YFC0400406)
文摘An organic macromolecule, poly(1-vinylimidazole), with an appropriate polymerization degree was proposed and mixed with water to form a novel aqueous absorbent for SO_2 capture. This aqueous solution absorbent has the advantages of simple preparation, good physicochemical properties, environment-friendliness, high ability in deep removal of SO_2, and excellent reusability. Moreover, pH-responsive behavior, pH buffering absorption mechanism, and their synergistic effect on absorption performance were revealed. The solubilities of SO_2 in the absorbent were measured in detail, and the results demonstrated excellent absorption capacity and recyclability. Then, mathematic models that describe SO_2 absorption equilibrium were established, and the corresponding parameters were estimated. More importantly, on the basis of model and experimental data, the absorption and desorption could maintain high efficiency within a wide operating region. In summary, this work provided a low-cost, efficient, and unique absorbent for SO_2 capture and verified its technical feasibility in industrial application.
基金supported by Center of Excellence in Pharmacology and Molecular Biology of Malaria and Cholangiocarcinoma,Chulabhorn International College of Medicine,Thammasat University the National Research University Project of Thailand(NRU)
文摘OBJECTIVE To formulate atractylodin-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles and characterize the prepared nanoparticle formulation.METHODS The nanoparticle formulation was developed using solvent displacement method.The encapsulation and loading efficiency were characterized and particle size,and zeta potential were determined by dynamic light scattering technique.Drug release was assessed in vitro.RESULTS The size(mean±SD of diameter) of the prepared atractylodin-loaded PLGA nanoparticles were(161.27 ± 1.87)nm with narrow size distribution(mean PDI:0.068±0.015) and zeta potential(28.83±0.35)mV.The encapsulation and loading efficiency were(48.31±0.83)% and(2.15±0.04)%,respectively.Drug release from atractylodin-loaded PLGA nanoparticles was observed up to(87.70±0.47)% in 72 h with biphasic manner.Moreover,the nanoparticles were found to be freely dispersible in water without aggregation.CONCLUSION Results suggest that PLGA nanoparticles may be used as an effective drug delivery system for atractylodin.The anti-cholangiocarcinoma activity of this nanoparticle formulation is required.
基金the National Natural Science Foundation of China(Nos.U21A6004 and 51991341)Science and Technology Major Project of Shanxi(No.202101030201022)Young Talents Program of Beijing(No.2018000020028G349)。
文摘Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of high purity s-SWCNTs.However,its chiral selectivity is relatively inferior to other s-SWCNT production methods.In this paper,the chiral selectivity of two polymers,poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(6,6′-{2,2′-bipyridine})](PFO-BPy)and poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl](PCz),which are representatives of widely used polyfluorene and polycarbazole families,respectively,were comparatively studied.Both polymers exhibited high selectivity for a subset of existing chiral species in each of the commercially available raw SWCNT materials(CoMoCAT,HiPco,and arc-discharge)which cover a diameter range of 0.6–1.8 nm.Less chiral species were selected by PFO-BPy from small diameter(<1 nm)raw SWCNT materials,while more from large diameter(>1.2 nm)raw materials.High chiral purity(6,5)(>99%)and(7,5)(>75%)solutions were extracted by PFO-BPy and PCz from CoMoCAT materials,respectively.The different chiral angle and diameter selections for different raw materials by both polymers were ascribed to their different geometrical structures and related polymer-tube interactions.Our work provides indispensable information for better understanding the mechanism of polymer wrapping method and improving extraction of single chirality sSWCNTs.
