Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,t...Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.展开更多
Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppre...Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.展开更多
不可控的锂枝晶生长、严重的体积膨胀以及脆弱的固态电解质中间相(SEI)严重制约了锂金属电池(LMBs)的实际应用。在本研究中,我们成功设计合成了一类具有碳纳米管基底的硫化超交联聚苯乙烯刷(CNT-g-sxPS),并将其用作新型的三维锂金属载体...不可控的锂枝晶生长、严重的体积膨胀以及脆弱的固态电解质中间相(SEI)严重制约了锂金属电池(LMBs)的实际应用。在本研究中,我们成功设计合成了一类具有碳纳米管基底的硫化超交联聚苯乙烯刷(CNT-g-sxPS),并将其用作新型的三维锂金属载体。CNT-g-sxPS的层次化大孔、中孔和微孔能够促进锂离子的传输,缓解锂负极的体积变化,提供高比表面积以降低局部电流密度,从而实现快速且均匀的锂沉积/剥离。同时,孔骨架表面均匀分布的含硫基团可以与锂原位反应生成含Li2S的SEI,有利于构筑稳定的负极/电解液界面。此外,碳纳米管基底还能提供快速的电子传输路径。因此,利用CNT-g-sxPS负载的锂金属负极(CNT-g-sxPS@Cu/Li)组装的Li|Li对称电池在1 mA cm^(-2)、1 mAh cm^(-2)下可稳定循环超过500 h。当与磷酸铁锂正极(LFP)匹配时,利用CNT-g-sxPS@Cu/Li负极组装的全电池在1 C下循环600圈后仍然具有101 mAh g^(-1)的放电比容量,容量保持率为77%。展开更多
Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful develo...Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful development of a facile one-step method to fabricate a series of novel triclosan poly-dopamine polypropylene(TPP)composite scaffolds and thereby effectively improve the biocompatibility and long-term antibacterial properties of PP scaffolds.The antibacterial triclosan can effectively interact with dopamine during biocompatible polydopamine formation on the PP scaffold by one-step green fab-rication.Thanks to the sustained release of triclosan from the biocompatible polydopamine coating,a 5mm×5mm sample of TPP-coated scaffold made with a triclosan concentration of 8 mg-mL^(-1)(referredto herein as TPP-8)exhibited a continuous antibacterial effect against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)for more than 15d,at maximum antibacterial volumes of 2 and 5mL,respectively.Our study establishes a new direction for facile long-term antibacterial studies for medical applications.展开更多
Lithium is considered to be the ‘‘holy grail” for the application of energy storage due to its highest theoretical capacity and lowest anode potential. However, one of the grand difficulties in the development of l...Lithium is considered to be the ‘‘holy grail” for the application of energy storage due to its highest theoretical capacity and lowest anode potential. However, one of the grand difficulties in the development of lithium-based batteries is the lithium dendrite growth that leads to capacity fading and electrode degradation over long-term cycling. Compared with conventional electrolyte modifications, artificial solid electrolyte interfaces(SEI) synthesis and framework designing approaches, tuning surface morphology of lithium anode is the direct route to induce homogeneous Li ion deposition. Due to the high chemical activity of lithium metal, however, controllable growth of lithium micro/nanostructures by traditionally chemical approaches is still a big challenge. Herein, we have developed a facile compression route to fabricate lithium anode with abundant stepped lithium structures. The electrochemical results demonstrate that the dendritic growth issue is effectively suppressed by orderly arranged stepped lithium structures. After 90 cycles, a high discharge capacity of 954 mAh g^(-1) is achieved, which is 2.7times that of the uncompressed lithium anode(342 mAh g). First-principles calculations reveal that the orderly arranged stepped lithium structures are lithiophilic active sites to adsorb Li ion, which contributes to homogeneous deposition of Li ion on lithium anode, eventually solving the lithium dendrite issue. This work paves a new road to suppress dendritic growth, which will provide some new ideas to design long recycling sodium, potassium and zinc, and other metal anode batteries.展开更多
We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp^(2)-H functionalizations.A variety of readily available 2-aminopyridines and 1,2,3-triazoles ...We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp^(2)-H functionalizations.A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized azaindoles.Mechanistic studies including DFT calculations unveil that relay carbenoidelectrophilic addition to pyridines and the sequential pyridyl Csp^(2)-H amination are involved in this transformation.The postsynthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.展开更多
The ever-growing demand for next-generation high-energy-density devices drives the development of lithium metal batteries with enough safety and high performance,in which quasi-solid-state composite electrolytes(QSCEs...The ever-growing demand for next-generation high-energy-density devices drives the development of lithium metal batteries with enough safety and high performance,in which quasi-solid-state composite electrolytes(QSCEs)with high ionic conductivity and lithium ion transference number(urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0001)are highly desirable.Herein,we successfully synthesize a kind of two-dimensional(2D)molecular brush(GO-g-PFIL)via grafting poly(ionic liquid)side-chain(poly(3-(3,3,4,4,4-pentafluorobutyl)-1-vinyl-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide),denoted as PFIL)on the surface of 2D graphene oxide(GO)sheet.GO-g-PFIL is used as multifunctional filler to prepare novel composite membranes and corresponding QSCEs(e.g.,QSCE-PH/GPFIL3/P).The as-obtained QSCE-PH/GPFIL3/P integrates features of PFIL side-chain-enhanced lithium ion conduction,poly(vinylidene fluoride-co-hexafluoropropene)backbone-induced flexibility,and GO-strengthened mechanical property.As a result,our ultrathin(21μm)self-supporting QSCE-PH/GPFIL3/P exhibits high ionic conductivity(3.24×10^(−4)S·cm^(−1))and excellent urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0002(0.82)at room temperature,and Li/LFP full cell with QSCE-PH/GPFIL3/P shows superior rate performance(high specific capacities of 79 mAh·g^(−1)at 30°C and 5 C)and excellent cycling performance(high capacity retention of 91%after 500 cycles at 80°C and 1 C).展开更多
Flame retardants play a crucial role in improving theflame retardant properties of polymer materials.In recent years,environmental problems caused byflame retar-dants have attracted widespread attention.It is urgent to ...Flame retardants play a crucial role in improving theflame retardant properties of polymer materials.In recent years,environmental problems caused byflame retar-dants have attracted widespread attention.It is urgent to use green and effective methods to prepareflame retardant polymers.Bioinspired nanocomposites with lay-ered structures seem to provide effective ideas,but in general,their hydrophilic raw materials limit their applications in certainfields.Here,we prepared biomimetic composites with a layered“brick-and-mortar”structure by gravity-induced depo-sition using polyimide as the polymer matrix and montmorillonite(MMT)as thefiller.The well-arranged structures of the composite material could isolate oxygen and prevent combustible gases from escaping.The gas barrier performance has been greatly improved,in which the water vapor transmission rate and the oxygen trans-mission rate decreased by 99.18%and three orders of magnitude,respectively.Theflame retardant performance has also been improved,and its limiting oxygen index can reach 67.9%.The polyimide matrix can be converted to water-insoluble by ther-mal imidization of water-soluble poly(amic acid)salt precursors,which endows the composites with low hygroscopicity.The coating containing MMT can protect against polyurethane(PU)foam fromfire.During the conical calorimetric test,the coated sample self-extinguished,and the peak heat release rate,total heat release,and total smoke production are significantly decreased by 53.39%,40.69%,and 53.03%,respectively.Taking advantage of these properties,this work utilizes a facile method to prepare biomimetic composites with low moisture absorption,excellent gas barrier properties,andflame retardancy,which have great application potential.展开更多
In this work,we study the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)structure in aqueous dispersion with small-angle X-ray scattering(SAXS).In-depth structure analysis is achieved based on a s...In this work,we study the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)structure in aqueous dispersion with small-angle X-ray scattering(SAXS).In-depth structure analysis is achieved based on a set of complementary and sophisticated algorithms,which provide not only shape and packing of chains but also 3D structure of the colloids.The structure information of the PEDOT chain was extracted from the well-known Guinier,Porod and pair distance distribution function(PDDF)analysis of the SAXS data,while the 3D modelling was achieved with the DAMMIF and DAMAVER programs in ATSAS software package.To the best of our knowledge,we first establish the 3D model of the PEDOT:PSS colloids’structure that will help people to understand the supramolecular assembly in aqueous dispersion,which sheds light on the solution structure study of polymers that are widely used in daily life.展开更多
Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by...Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by severe polysulfide shuttle effect and sluggish redox kinetics in sulfur cathodes greatly impede the practical application of Li-S batteries.Herein,a new class of nanonetworkstructured carbon decorated with oxygen-vacancy-containing cerium oxide nanoparticles(NSC-CeO_(2−x)),in which carbon skeleton is composed of highly conductive carbon nanotube core welded by hybrid carbon shell,has been developed via one-step heating treatment of hybrid molecular brush and further employed as functional interlayer to modify separator of Li-S battery.Owing to the synergistic effect of the highly active CeO_(2−x)nanoparticles and the threedimensional carbon nanonetwork in enhancing the preservation of the soluble polysulfides and boosting the redox kinetics of sulfur species,the NSC-CeO_(2−x)significantly promotes the electrochemical performance of sulfur cathode.As a result,the as-constructed Li-S batteries exhibit an ultrahigh initial sulfur utilization of 92.9%and an extremely large capacity of 751mA h g^(−1) at a high rate of 5 C.Remarkably,a stable capacity of 728 mA h g^(−1)over 300 cycles at 1 C is also achieved.展开更多
Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of mo...Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of motor amphiphiles could be switched from bicontinuous calabashes to nanoribbons or from vesicles to nanoribbons by modulating rotor orientation direction with dual light/heat stimuli to influence spontaneous curvature in assemblies.The photoisomerization and thermal helix inversion processes of molecular motors have been studied at the molecular level,and the transformation of supramolecular assemblies has been investigated at the microscopic level.The morphological evolution of the calabash-shaped assembly can be kinetically captured,suggesting that the bicontinuous calabash-shaped structures are different from the bowl-shaped aggregates based on solvent-driven assembly upon the addition of non-solvent or solvent.The investigation of dual optical/thermal control of rotor orientation can provide a new strategy for tuning the geometric curvature and chirality of nanoassemblies at the nanoscale,arriving ultimately the clusteroluminescence through-space electronic communication at responsive supramolecular nanosystems.展开更多
To achieve highly-efficient organic light-emitting diodes(OLEDs),great efforts have been devoted into constructing thermally activated delayed fluorescence(TADF)with high horizontal dipole ratios(Θ//).Here,we propose...To achieve highly-efficient organic light-emitting diodes(OLEDs),great efforts have been devoted into constructing thermally activated delayed fluorescence(TADF)with high horizontal dipole ratios(Θ//).Here,we proposed a design strategy by integrating a rigid electron-accepting oxygen-bridged boron core with triple electron-donating groups,which exhibited a“shamrock-shape”,namely BO-3DMAC and BO-3DPAC.Benefiting from the rigid and large-planar skeletons brought by shamrock-shaped design,BO-3DMAC and BO-3DPAC exhibit highΘ//of 84%/70%and 93%/94%in neat/doped films,respectively,and finally furnish excellent external quantum efficiencies(EQEs)of up to 28.3%and 38.7%in 20 wt%doped OLEDs with sky-blue emission,as well as adequate EQEs of up to 21.0%and 16.7%in nondoped OLEDs.This work unveils a promising strategy to establish high-Θ//TADF emitters by constructing large-planar molecular structures using shamrock-shaped design.展开更多
A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling re...A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.展开更多
A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the exis...A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the existence of meso-and rac-configuration in solid structure. Nickel complexes after activation by MAO were screened for ethylene polymerization to evaluate backbone substituent effect on synthesis of bimodal PE. Acenaphthyl nickel complex with planar backbone afforded a bimodal PE with a broad polydispersity, whereas camphyl nickel complex with rigid and bulky backbone afforded a monomodal PE with a narrow polydispersity. Steric effect of aniline moiety for acenaphthyl nickel complex was also examined, and bimodal PE with dominant high-molecular-weight fraction was obtained by modifying substituents on aniline moiety.展开更多
Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefin...Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.展开更多
High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design st...High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design strategy for non-fluorinated intrinsic low-k and low-loss polyimides is reported by fully considering the secondary relaxation behaviors of the polymer chains.A new amorphous non-fluorinated polymer(TmBPPA)with a k value of 2.23 and a loss tangent lower than 3.94×10^-3 at 104 Hz has been designed and synthesized,which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in literature.Meanwhile,TmBPPA exhibits excellent overall properties,such as excellent thermostability,good mechanical properties,low moisture absorption,and high bonding strength.As high-performance flexible circuit materials,all these characteristics are highly expected to meet the present and future demands for high density,high speed,and high frequency electronic circuit used in 5 G wireless networks.展开更多
Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were pre...Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were prepared from the amphiphilic block copolymer poly（ethylene glycol）-poly（e-caprolactone） （PEG-b-PCL） with different targeting ligands cRGD and scFv-ErbB single chain antibody conjugated to the distal ends of PEG block. The breast cancer animal model was established by subcutaneous injecting the BT474 cells into the BALB/c-nu female nude mice and then employed to assess the potential of the dual ligand targeted magnetic micelles as a novel MRI contrast agent on a 1.5 T clinical MR/scanner. The T2 signal intensity of the tumor in animals receiving the dual ligand targeted magnetic micelles via tail vein decreased more significantly than the single ligand targeted and nontargeted magnetic micelles. These results indicate that the dual ligand targeted magnetic micelles, cRGD/scFv-ErbB-PEG-PCL-SPION, have great potential to act as a new type of effective nanoscale MRI contrast agent for early diagnosis of breast cancer.展开更多
基金the financial support of the Training Program of the Major Research Plan of the National Natural Science Foundation of China(92061124)the National Natural Science Foundation of China(21975292,21978331,22068008,and 52101186)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2021A1515010167 and 2022A1515011196)the Guangzhou Key R&D Program/Plan Unveiled Flagship Project(20220602JBGS02)the Guangzhou Basic and Applied Basic Research Project(202201011449)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202220 and FC202216)。
文摘Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.
文摘Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.
文摘不可控的锂枝晶生长、严重的体积膨胀以及脆弱的固态电解质中间相(SEI)严重制约了锂金属电池(LMBs)的实际应用。在本研究中,我们成功设计合成了一类具有碳纳米管基底的硫化超交联聚苯乙烯刷(CNT-g-sxPS),并将其用作新型的三维锂金属载体。CNT-g-sxPS的层次化大孔、中孔和微孔能够促进锂离子的传输,缓解锂负极的体积变化,提供高比表面积以降低局部电流密度,从而实现快速且均匀的锂沉积/剥离。同时,孔骨架表面均匀分布的含硫基团可以与锂原位反应生成含Li2S的SEI,有利于构筑稳定的负极/电解液界面。此外,碳纳米管基底还能提供快速的电子传输路径。因此,利用CNT-g-sxPS负载的锂金属负极(CNT-g-sxPS@Cu/Li)组装的Li|Li对称电池在1 mA cm^(-2)、1 mAh cm^(-2)下可稳定循环超过500 h。当与磷酸铁锂正极(LFP)匹配时,利用CNT-g-sxPS@Cu/Li负极组装的全电池在1 C下循环600圈后仍然具有101 mAh g^(-1)的放电比容量,容量保持率为77%。
基金support from the project of the Science and Technology Program of Guangzhou(201704020059 and 201803010074).
文摘Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful development of a facile one-step method to fabricate a series of novel triclosan poly-dopamine polypropylene(TPP)composite scaffolds and thereby effectively improve the biocompatibility and long-term antibacterial properties of PP scaffolds.The antibacterial triclosan can effectively interact with dopamine during biocompatible polydopamine formation on the PP scaffold by one-step green fab-rication.Thanks to the sustained release of triclosan from the biocompatible polydopamine coating,a 5mm×5mm sample of TPP-coated scaffold made with a triclosan concentration of 8 mg-mL^(-1)(referredto herein as TPP-8)exhibited a continuous antibacterial effect against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)for more than 15d,at maximum antibacterial volumes of 2 and 5mL,respectively.Our study establishes a new direction for facile long-term antibacterial studies for medical applications.
基金financially supported by the National Natural Science Foundation of China(22075035)the Key Research Project of Liaoning Province(2020JH2/1070008)。
文摘Lithium is considered to be the ‘‘holy grail” for the application of energy storage due to its highest theoretical capacity and lowest anode potential. However, one of the grand difficulties in the development of lithium-based batteries is the lithium dendrite growth that leads to capacity fading and electrode degradation over long-term cycling. Compared with conventional electrolyte modifications, artificial solid electrolyte interfaces(SEI) synthesis and framework designing approaches, tuning surface morphology of lithium anode is the direct route to induce homogeneous Li ion deposition. Due to the high chemical activity of lithium metal, however, controllable growth of lithium micro/nanostructures by traditionally chemical approaches is still a big challenge. Herein, we have developed a facile compression route to fabricate lithium anode with abundant stepped lithium structures. The electrochemical results demonstrate that the dendritic growth issue is effectively suppressed by orderly arranged stepped lithium structures. After 90 cycles, a high discharge capacity of 954 mAh g^(-1) is achieved, which is 2.7times that of the uncompressed lithium anode(342 mAh g). First-principles calculations reveal that the orderly arranged stepped lithium structures are lithiophilic active sites to adsorb Li ion, which contributes to homogeneous deposition of Li ion on lithium anode, eventually solving the lithium dendrite issue. This work paves a new road to suppress dendritic growth, which will provide some new ideas to design long recycling sodium, potassium and zinc, and other metal anode batteries.
基金supported by the National Natural Science Foundation of China(22271100,21973113)the Key-Area Research and Development Program of Guangdong Province(2020-B010188001)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(2023A1515010070)the China Postdoctoral Science Foundation(2021M701243)。
文摘We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp^(2)-H functionalizations.A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized azaindoles.Mechanistic studies including DFT calculations unveil that relay carbenoidelectrophilic addition to pyridines and the sequential pyridyl Csp^(2)-H amination are involved in this transformation.The postsynthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.
基金This work was supported by the projects of National Key Research and Development Program of China(2021YFF0500600)National Natural Science Foundation of China(51925308)+1 种基金Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23yxqntdo02)Natural Science Foundation of Guangdong Province(2023A1515030160,2022A1515011778).
文摘The ever-growing demand for next-generation high-energy-density devices drives the development of lithium metal batteries with enough safety and high performance,in which quasi-solid-state composite electrolytes(QSCEs)with high ionic conductivity and lithium ion transference number(urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0001)are highly desirable.Herein,we successfully synthesize a kind of two-dimensional(2D)molecular brush(GO-g-PFIL)via grafting poly(ionic liquid)side-chain(poly(3-(3,3,4,4,4-pentafluorobutyl)-1-vinyl-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide),denoted as PFIL)on the surface of 2D graphene oxide(GO)sheet.GO-g-PFIL is used as multifunctional filler to prepare novel composite membranes and corresponding QSCEs(e.g.,QSCE-PH/GPFIL3/P).The as-obtained QSCE-PH/GPFIL3/P integrates features of PFIL side-chain-enhanced lithium ion conduction,poly(vinylidene fluoride-co-hexafluoropropene)backbone-induced flexibility,and GO-strengthened mechanical property.As a result,our ultrathin(21μm)self-supporting QSCE-PH/GPFIL3/P exhibits high ionic conductivity(3.24×10^(−4)S·cm^(−1))and excellent urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0002(0.82)at room temperature,and Li/LFP full cell with QSCE-PH/GPFIL3/P shows superior rate performance(high specific capacities of 79 mAh·g^(−1)at 30°C and 5 C)and excellent cycling performance(high capacity retention of 91%after 500 cycles at 80°C and 1 C).
基金Ministry of Science and Technology,Grant/Award Number:2022YFB3806601National Natural Science Foundation of China,Grant/Award Numbers:U20A20255,51873239,52103022,52203286+2 种基金Guangdong Provincial Department of Science and Technology,Grant/Award Numbers:2020B010182001,2020B010179001,2021A1515010664,2019B040401002Fellowship of China Postdoctoral Science Foundation,Grant/Award Number:2022M723572Guangxi Provincial Department of Science and Technology,Grant/Award Number:GLESI-KFKY2301013。
文摘Flame retardants play a crucial role in improving theflame retardant properties of polymer materials.In recent years,environmental problems caused byflame retar-dants have attracted widespread attention.It is urgent to use green and effective methods to prepareflame retardant polymers.Bioinspired nanocomposites with lay-ered structures seem to provide effective ideas,but in general,their hydrophilic raw materials limit their applications in certainfields.Here,we prepared biomimetic composites with a layered“brick-and-mortar”structure by gravity-induced depo-sition using polyimide as the polymer matrix and montmorillonite(MMT)as thefiller.The well-arranged structures of the composite material could isolate oxygen and prevent combustible gases from escaping.The gas barrier performance has been greatly improved,in which the water vapor transmission rate and the oxygen trans-mission rate decreased by 99.18%and three orders of magnitude,respectively.Theflame retardant performance has also been improved,and its limiting oxygen index can reach 67.9%.The polyimide matrix can be converted to water-insoluble by ther-mal imidization of water-soluble poly(amic acid)salt precursors,which endows the composites with low hygroscopicity.The coating containing MMT can protect against polyurethane(PU)foam fromfire.During the conical calorimetric test,the coated sample self-extinguished,and the peak heat release rate,total heat release,and total smoke production are significantly decreased by 53.39%,40.69%,and 53.03%,respectively.Taking advantage of these properties,this work utilizes a facile method to prepare biomimetic composites with low moisture absorption,excellent gas barrier properties,andflame retardancy,which have great application potential.
基金financial supports from the National Natural Science Foundation of China(Nos.U2032101 and 11905306)Fundamental Research Funds for the Central Universities(No.19lgpy14)“100 Top Talents Program”of Sun Yat-sen University。
文摘In this work,we study the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)structure in aqueous dispersion with small-angle X-ray scattering(SAXS).In-depth structure analysis is achieved based on a set of complementary and sophisticated algorithms,which provide not only shape and packing of chains but also 3D structure of the colloids.The structure information of the PEDOT chain was extracted from the well-known Guinier,Porod and pair distance distribution function(PDDF)analysis of the SAXS data,while the 3D modelling was achieved with the DAMMIF and DAMAVER programs in ATSAS software package.To the best of our knowledge,we first establish the 3D model of the PEDOT:PSS colloids’structure that will help people to understand the supramolecular assembly in aqueous dispersion,which sheds light on the solution structure study of polymers that are widely used in daily life.
基金National Natural Science Foundation of China,Grant/Award Numbers:51872336,51925308,52172061National Key Research and Development Program of China,Grant/Award Number:2021YFF0500600+2 种基金Pearl River Talent Plan of Guangdong,Grant/Award Number:2017GC010612Natural Science Foundation of Guangdong,Grant/Award Number:2021A1515011617Science and Technology Program of Guangzhou,Grant/Award Numbers:202102021111,202002020041。
文摘Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by severe polysulfide shuttle effect and sluggish redox kinetics in sulfur cathodes greatly impede the practical application of Li-S batteries.Herein,a new class of nanonetworkstructured carbon decorated with oxygen-vacancy-containing cerium oxide nanoparticles(NSC-CeO_(2−x)),in which carbon skeleton is composed of highly conductive carbon nanotube core welded by hybrid carbon shell,has been developed via one-step heating treatment of hybrid molecular brush and further employed as functional interlayer to modify separator of Li-S battery.Owing to the synergistic effect of the highly active CeO_(2−x)nanoparticles and the threedimensional carbon nanonetwork in enhancing the preservation of the soluble polysulfides and boosting the redox kinetics of sulfur species,the NSC-CeO_(2−x)significantly promotes the electrochemical performance of sulfur cathode.As a result,the as-constructed Li-S batteries exhibit an ultrahigh initial sulfur utilization of 92.9%and an extremely large capacity of 751mA h g^(−1) at a high rate of 5 C.Remarkably,a stable capacity of 728 mA h g^(−1)over 300 cycles at 1 C is also achieved.
基金Science and Technology Program of Guangzhou,Grant/Award Number:201804010017National Natural Science Foundation of China,Grant/Award Number:21374137+1 种基金Natural Science Foundation of Guangdong Province,Grant/Award Number:2014A030313194Science and Technology Program of Guangdong Province,Grant/Award Number:2017A050506021。
文摘Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of motor amphiphiles could be switched from bicontinuous calabashes to nanoribbons or from vesicles to nanoribbons by modulating rotor orientation direction with dual light/heat stimuli to influence spontaneous curvature in assemblies.The photoisomerization and thermal helix inversion processes of molecular motors have been studied at the molecular level,and the transformation of supramolecular assemblies has been investigated at the microscopic level.The morphological evolution of the calabash-shaped assembly can be kinetically captured,suggesting that the bicontinuous calabash-shaped structures are different from the bowl-shaped aggregates based on solvent-driven assembly upon the addition of non-solvent or solvent.The investigation of dual optical/thermal control of rotor orientation can provide a new strategy for tuning the geometric curvature and chirality of nanoassemblies at the nanoscale,arriving ultimately the clusteroluminescence through-space electronic communication at responsive supramolecular nanosystems.
基金Natural Science Foundation of China,Grant/Award Numbers:51733010,52073316Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2022B1515020052,2021A1515110119。
文摘To achieve highly-efficient organic light-emitting diodes(OLEDs),great efforts have been devoted into constructing thermally activated delayed fluorescence(TADF)with high horizontal dipole ratios(Θ//).Here,we proposed a design strategy by integrating a rigid electron-accepting oxygen-bridged boron core with triple electron-donating groups,which exhibited a“shamrock-shape”,namely BO-3DMAC and BO-3DPAC.Benefiting from the rigid and large-planar skeletons brought by shamrock-shaped design,BO-3DMAC and BO-3DPAC exhibit highΘ//of 84%/70%and 93%/94%in neat/doped films,respectively,and finally furnish excellent external quantum efficiencies(EQEs)of up to 28.3%and 38.7%in 20 wt%doped OLEDs with sky-blue emission,as well as adequate EQEs of up to 21.0%and 16.7%in nondoped OLEDs.This work unveils a promising strategy to establish high-Θ//TADF emitters by constructing large-planar molecular structures using shamrock-shaped design.
基金financial support by the National 973 Program of China (No. 2014CB643605)the National Natural Science Foundation of China (Nos. 51373204 and 51873239)+3 种基金the Science and Technology Project of Guangdong Province (Nos. 2015B090915003 and 2015B090913003)the China Postdoctoral Science Foundation (No. 2017M612801)the Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (No. 2016TX03C295)the Fundamental Research Funds for the Central Universities (No. 161gzd08)
文摘A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.
基金supported by NSFC (Nos. 21274167, 51173209 and 21174164)CNPC Innovation Foundationthe Fundamental Research Funds for the Central Universities (Project 10lgpy10)
文摘A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the existence of meso-and rac-configuration in solid structure. Nickel complexes after activation by MAO were screened for ethylene polymerization to evaluate backbone substituent effect on synthesis of bimodal PE. Acenaphthyl nickel complex with planar backbone afforded a bimodal PE with a broad polydispersity, whereas camphyl nickel complex with rigid and bulky backbone afforded a monomodal PE with a narrow polydispersity. Steric effect of aniline moiety for acenaphthyl nickel complex was also examined, and bimodal PE with dominant high-molecular-weight fraction was obtained by modifying substituents on aniline moiety.
基金financially supported by the National Natural Science Foundation of China (Nos. 21674130, 51873234)Natural Science Foundation of Guangdong Province (No. 2017A030310 349)+1 种基金Fundamental Research Funds for the Central Universities (No. 17lgjc02)PetroChina Innovation Foundation (No. 2017D-5007-0505)
文摘Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.
基金finincially supported by the National Natural Science Foundation of China (Nos. 51373204 and 51873239)the National 973 Program of China (No. 2014CB643605)+3 种基金the Science and Technology Project of Guangdong Province (Nos. 2015B090915003 and 2015B090913003)the Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (No. 2016TX03C295)the China Postdoctoral Science Foundation (No. 2017M612801)the Fundamental Research Funds of Sun Yat-sen University
文摘High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design strategy for non-fluorinated intrinsic low-k and low-loss polyimides is reported by fully considering the secondary relaxation behaviors of the polymer chains.A new amorphous non-fluorinated polymer(TmBPPA)with a k value of 2.23 and a loss tangent lower than 3.94×10^-3 at 104 Hz has been designed and synthesized,which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in literature.Meanwhile,TmBPPA exhibits excellent overall properties,such as excellent thermostability,good mechanical properties,low moisture absorption,and high bonding strength.As high-performance flexible circuit materials,all these characteristics are highly expected to meet the present and future demands for high density,high speed,and high frequency electronic circuit used in 5 G wireless networks.
基金supported by the 863 Programs of China(No.2009AA03Z310)National Natural Science Foundation of China(Nos.21174166,30973419)+5 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No.20100171110011)the Postdoctoral Foundation(No.201003370)Natural Science Foundation(Nos.9351027501000003,S2011020003140)S&T Programs of Guangdong Province(Nos.2010B031500011,2009B030803003,2009B030801107,2012B031800135)SYSU Projects for Promotion of Key and Emerging Interdisciplinary Researches(10ykjc18)Young Teachers(11lgpy44)
文摘Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were prepared from the amphiphilic block copolymer poly（ethylene glycol）-poly（e-caprolactone） （PEG-b-PCL） with different targeting ligands cRGD and scFv-ErbB single chain antibody conjugated to the distal ends of PEG block. The breast cancer animal model was established by subcutaneous injecting the BT474 cells into the BALB/c-nu female nude mice and then employed to assess the potential of the dual ligand targeted magnetic micelles as a novel MRI contrast agent on a 1.5 T clinical MR/scanner. The T2 signal intensity of the tumor in animals receiving the dual ligand targeted magnetic micelles via tail vein decreased more significantly than the single ligand targeted and nontargeted magnetic micelles. These results indicate that the dual ligand targeted magnetic micelles, cRGD/scFv-ErbB-PEG-PCL-SPION, have great potential to act as a new type of effective nanoscale MRI contrast agent for early diagnosis of breast cancer.
