The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functiona...The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functionalized solution for introducing the OH- and groups, and then the heparin was immobilized on the active TiO2 films through the electrostatic self assembly technology. It is shown that the heparinized films are mainly composed of anatase and rutile with smooth and dense surface. In vitro blood compatibility was evaluated by haemolysis test, clotting time and platelet adhesion behavior tests. The results show that the haemocompatibility of the alloy could be significantly improved by surface heparinization.展开更多
Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic a...Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic acid）（PSS） and poly（diallyl-dimethylammonium chloride）（PDADMAC） to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue（MB）. Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.展开更多
The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1...The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1,5-pentanediami ne ligand(H2L) . It was obtained in situ in a one-step,metal-templated condensa tion of salicylaldehyde with 1,5-pentanediamine(cadaverine,biogenic polyamine) and characterized by microanalysis and spectroscopic(IR,ESI-MS,UV-Vis,and 1 H NMR) data. The [La(NO3) 3(μ-H2L) 2]∞ complex displayed 10-coordinate distorted bicapped dodecahedron geometry with unusual coordination pattern of undeprotonat ed salicylaldimines which acted as μ-bridging ditopic ligands using exclusivel y the oxygens as donor atoms with the nitrogen atoms not being involved in the c oordination environment.展开更多
Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can ...Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can drive on the ground, autonomously accomplish self-assembly and then fly in the air coordinately. Mechanical and electrical designs of a DSFR module, as well as the kinematics and dynamics analysis, are specifically investigated. Meanwhile, this paper brings forward a generalized adjacency matrix to describe configurations of DSFR structures. Also, the distributed flight control model is established for vertical taking-off and horizontal hovering, which can be applied to control of DSFR systems with arbitrary configurations. Finally, some experiments are carried out to testify and validate the DSFR design, the autonomous self-assembly strategy and the distributed flight control laws.展开更多
The mesoporous Ti O2 has been synthesized by evaporation induced self assembly(EISA) method. The thermogravimetric/differential scanning calorimetric(TG/DSC), X-ray diffraction(XRD), high-resolution transmission elect...The mesoporous Ti O2 has been synthesized by evaporation induced self assembly(EISA) method. The thermogravimetric/differential scanning calorimetric(TG/DSC), X-ray diffraction(XRD), high-resolution transmission electron microscopy(HR-TEM) and N2 adsorption desorption and adsorption are used to study the effects of the synthesized process condition on the microstructure of the as-synthesized mesoporous Ti O2. The photocatalytic performances of as-synthesized samples are evaluated by the degradation of the formaldehyde under ultraviolet light irradiations. The results demonstrate that the as-synthesized mesoporous Ti O2 are anatase with the uniform size about 20-40 nm. The sample is prepared using cetyltrimethyl ammonium bromide(CTAB) as the template with average pore size distribution of 8.12 nm, specific surface area of 68.47 m2/g and pore volume of 0.213 m L/g. The samples show decomposition of formaldehyde 95.8% under ultraviolet light irradiations for 90 min. These results provide a basic experimental process for preparation mesoporous Ti O2, which will posses a broad prospect in terms of the applications in improving indoor air quality.展开更多
The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur...The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.展开更多
In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain ＇y-alumina in the nano scale. S...In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain ＇y-alumina in the nano scale. Scanning electron microscopy images of the prepared γ-alumina showed big and strong agglomeration of the nanoparticles indicating that these nanoparticles have strong surface forces. Transmission electron microscopy images confirmed that the γ-alumina nanoparticles 3-7 nm in size were converted to uniform spherical shape in the size range of 1-2 mm after shaking with dimethyl disulfide in the presence of n-hexane at room temperature. This phenomenon did not appear in the case of alumina in the micro scale. The surface properties of the prepared γ-alumina in the nano scale were characterized and compared with the γ-alumina in the micro scale by using low temperature nitrogen adsorption-desorption system, indicating that the specific surface area of the prepared γ-alumina nanoparticles is larger than that of the γ-alumina in the micro scale. Furthermore, micro- and meso-pores were observed for the if-alumina nanoparticles while only mesoporous structure was detected for the γ-alumina in the micro scale. These experimental results suggested that the self assembly behavior of the γ-alumina nanoparticles may be due to the selective adsorption ofdimethyl disulfide in the micropores of these nanoparticles to act as bridge linking the nanoparticles.展开更多
Pepsin was assembled on the surface of prepared poly(ethylene terephthalate)(PET-NH3^+) substrates.The composition and structure of the pepsin/PET-NH3^+ assembling films in different condition were characterized by X-...Pepsin was assembled on the surface of prepared poly(ethylene terephthalate)(PET-NH3^+) substrates.The composition and structure of the pepsin/PET-NH3^+ assembling films in different condition were characterized by X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM).展开更多
Perfluorooctanoic acid-modified CsPbBr_(3) perovskite quantum dots(F-PQDs)are used as both luminescence centers and photocatalysts to prepare organic-inorganic nanohybrid assemblies.Polymerizationinduced self-assembly...Perfluorooctanoic acid-modified CsPbBr_(3) perovskite quantum dots(F-PQDs)are used as both luminescence centers and photocatalysts to prepare organic-inorganic nanohybrid assemblies.Polymerizationinduced self-assembly(PISA)technology of poly(poly(ethylene glycol)monomethyl ether methacrylate)-b-poly(perfluorooctyl)ethyl methacrylate copolymers(POEGMA-b-PFOEMA)via photo-induced electron/energy transfer RAFT(PET-RAFT)simplifies the synthetic steps of hybrid nanoparticles and enables the in situ encapsulation of PQDs through the dipole-dipole interaction based on the fluorocarbon chain on F-PQDs’surface and FOEMA.The insolubility of the PFOEMA block with liquid crystal properties allows for effective modulation of the hybrid nanostructure in toluene.Modulation of the block length achieves the transition from nanorods to spindle-like nano-assemblies and these hybrid nanoparticles possess PQDs’inherent fluorescence and enhanced stability.This strategy simplifies the preparation scheme of a PQD/polymer composite and provides a new perspective for the design of organic-inorganic hybrid materials through the photo-PISA strategy.展开更多
pH-sensitive wettability of polystyrene-b-poly（4-vinylpyridine） （PS-b-P4VP） self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hyd...pH-sensitive wettability of polystyrene-b-poly（4-vinylpyridine） （PS-b-P4VP） self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.展开更多
Compared with noble metals, improving the sensitivity of semiconducting surface-enhanced Raman scattering(SERS) substrates is of great significance to their fundamental research and practical application of Raman spec...Compared with noble metals, improving the sensitivity of semiconducting surface-enhanced Raman scattering(SERS) substrates is of great significance to their fundamental research and practical application of Raman spectroscopy. Herein, a simple chemical method is developed to synthesize a rhenium trioxide(ReO_(3)) microtubes assembled with highly crystalline nanoparticles. The ReO_(3) microtubes show a strong and well-defined surface plasmon resonance(SPR) behavior in visible region, which is rare for non-noble metals. As a low-cost SERS substrate, the plasmonic ReO_(3) microtubes exhibit a Raman enhancement factor of 8.9×10^(5) and a lowest detection limit of 1.0×10^(-9) mol/L for phenolic pollutants. Moreover, these ReO_(3) microtubule SERS substrates show excellent chemical stability and can resist the corrosion of strong acids and bases.展开更多
Novel three-dimensional(3D)foam-like porous carbon architectures with homogeneous N doping and unique mesopore-in-macropore structures have been fabricated from a metal–organic complex via a simple template-free soli...Novel three-dimensional(3D)foam-like porous carbon architectures with homogeneous N doping and unique mesopore-in-macropore structures have been fabricated from a metal–organic complex via a simple template-free solid state method,which have a high specific surface area(2732 m^(2)g^(−1)),large pore volume(3.31 cm^(3)g^(−1)),interconnected hierarchical pore structures with macro/meso/micro multimodal distribution and abundant surface functionality N doping(5.36 wt%).These characteristics give high catalytic performance for oxygen reduction with an onset potential of 0.98 V[versus reversible hydrogen electrode(RHE)]and a half-wave potential of 0.83 V(versus RHE)in alkaline media,which are comparable with those of the state-of-the-art platinum/carbon catalyst and many noble metal free catalysts.These results demonstrate the significant advantages of the unique mesopore-in-macropore porous structures with efficient heteroatom doping,which provides abundant accessible active sites for high mass and charge transports.The present work provides a new,simple and environmentally safe synthesis strategy for the preparation of 3D porous carbon architectures for use as efficient electrochemical energy devices and gives good insight into the fabrication of advanced nanostructured materials.展开更多
Nanohybrids have greatly promoted the application of nanomaterials in real world problems,since they not only present the individual advanced properties of each material,but can also realize the amplification of the f...Nanohybrids have greatly promoted the application of nanomaterials in real world problems,since they not only present the individual advanced properties of each material,but can also realize the amplification of the functions of the combined materials.Here,we assembled up-conversion nanoparticles NaYF_(4),Yb/Er@NaYF_(4)(UCNPs)and MnFe_(2)O_(4)(MF)into a multi-functional nanohybrid through direct coordination using polyacrylic acid(PAA)as the surficial bridging linker.Afterwards,the photosensitizer molecules Rose Bengal(RB)and PEG-COOH were covalently grafted onto the nanohybrid.UCNPs effectively stimulated RB by means of fluorescence resonance energy transfer effects to convert O_(2) to 1O_(2).Meanwhile,the MF NPs worked as a Fenton catalyst to continuously generate O_(2) by decomposing H_(2)O_(2) in the H_(2)O_(2) over-expression tumor micro-environment.Thus,a comprehensive therapeutic system was successfully constructed,which can efficiently perform photodynamic therapy(PDT)of hypoxic tumors under the excitation of a 980 nm laser.This work explored a new method for the assembly of nanohybrids using heterogeneous nanomaterials by coordination with bridging ligands between NPs and provided a versatile PDT candidate for hypoxic tumors.展开更多
The reaction of UO_(2)(OAc)_(2) and Na_(9)[A-PW_(9)O_(34)]in solution with different pH values leads to the formation of two Keggin-type sandwich polyoxometalates,namely Na11H(H_(2)O)_(31)[Na(UO_(2))(A-PW_(9)O_(34))]_...The reaction of UO_(2)(OAc)_(2) and Na_(9)[A-PW_(9)O_(34)]in solution with different pH values leads to the formation of two Keggin-type sandwich polyoxometalates,namely Na11H(H_(2)O)_(31)[Na(UO_(2))(A-PW_(9)O_(34))]_(2)·7H_(2)O(1)and Na_(12)(H_(2)O)_(29)[Na(UO_(2))(A-PW_(9)O_(34))]_(2)·7H_(2)O(2),which have been characterized by single-crystal X-ray diffraction,FT-IR spectroscopy,and PXRD techniques.Compounds 1 and 2 crystallize in similar conditions with different pH values and show similar sandwich crystal structures except that one extra Na(I)ion acts as a bridging linker in compound 2 than in 1.It is notable that 1 exhibits excellent catalytic activity for the synthesis of sulfonyl pyrazoles via the condensation and cyclization reaction of sulfonyl hydrazides with 1,3-diketones,and the yield of the desired product is up to 99%.This is the first report to investigate the catalytic properties of U-containing polyoxometalates.展开更多
Lithium-sulfur batteries(LSBs)are broadly considered to be the most promising next-generation energy storage because of their ultrahigh theoretical energy density and cost-effectiveness.However,the“shuttle effect”an...Lithium-sulfur batteries(LSBs)are broadly considered to be the most promising next-generation energy storage because of their ultrahigh theoretical energy density and cost-effectiveness.However,the“shuttle effect”and sluggish conversion kinetics of polysulfides severely hinder their practical application.To address these challenges,a unique Co-doped MnO_(2) nanorod network layer with oxygen vacancies(Co-MnO_(x))was devised by self-assembly on a commercial separator through the chemical growth method for high-performance LSBs.The Co-MnO_(x) modified separators(Co-MnO_(x)@PP)not only effectively alleviate the“shuttle effects”but also accelerate the redox conversion of polysulfides.More importantly,the Co-MnO_(x)@PP demonstrated superior thermostability and flame-retardant properties owing to the chemical growth method.The LSBs with Co-MnO_(x)@PP separators exhibited a high reversible capacity of 902.0 mA h g^(-1) and 562.2 mA h g^(-1) at 0.5 C for 20℃ and 60℃ after 200 cycles,respectively.Even at 3 C,after 500 cycles,a superb cycling performance of 715.2 mA h g^(-1) with an ultra-low decay of 0.069%for each cycle was achieved.Therefore,this proposed strategy of a Co-doped MnO_(2) nanorod network layer with oxygen vacancies will provide a new route for rationally devising durable and efficient LSBs.展开更多
MXene is a new 2D transition metal carbide possessing metallic conductivity and hydrophilic surfaces.It has drawn widespread attention as a potential material for electrode use.However,the applications of MXene are li...MXene is a new 2D transition metal carbide possessing metallic conductivity and hydrophilic surfaces.It has drawn widespread attention as a potential material for electrode use.However,the applications of MXene are limited by its property of low electrical capacity.In this paper,a novel MnO_(2)/MXene composite is prepared by electrostatic self-assembly.Firstly,delaminated MnO_(2)nanosheets are obtained through the intercalation delamination of multilayered H-MnO_(2)in a cationic Gemini surfactant(Gem)solution,leading to a positively charged surface.Then,the positive MnO_(2)nanosheets are assembled on negative MXene nanosheets through electrostatic self-assembly to form a MnO_(2)/MXene composite.The characterization results show that the MnO_(2)nanosheets are intimately assembled on the MXene nanosheets.As an electrode material,the MnO_(2)/MXene composite displays a specific capacitance of 340 F g^(−1)at 1 A g^(−1),which is three times the performance of an MXene electrode.In addition,the MnO_(2)/MXene electrode shows a high retention rate(90.3%retention at 10 A g^(−1))and good cycling life(87.6%of the initial specific capacitance is retained after 2000 cycles at 4 A g^(−1)).The properties of the proposed composite are attributed to the excellent conductivity of MXene and the high specific capacitance of MnO_(2).展开更多
Two porphyrin-based coordination frameworks,[Ag_(2)(TPyP)Sn(OH)_(2)](NO_(3))_(2)·(solv)x(1)and[Ag_(2)(TPyP)Sn(INA)_(2)](OTf)_(2)·(CH_(3)CN)_(2)(2)(INA=isonicotinato anion,OTf=CF_(3)SO_(3)^(−)),were construct...Two porphyrin-based coordination frameworks,[Ag_(2)(TPyP)Sn(OH)_(2)](NO_(3))_(2)·(solv)x(1)and[Ag_(2)(TPyP)Sn(INA)_(2)](OTf)_(2)·(CH_(3)CN)_(2)(2)(INA=isonicotinato anion,OTf=CF_(3)SO_(3)^(−)),were constructed by the selfassembly of hexacoordinated(meso-tetra-(4-pyridyl)porphyrinato)Sn(IV)building blocks with Ag(Ⅰ)ions.They were characterized using elemental analysis,UV-visible spectroscopy,fluorescence spectroscopy,FT-IR,field-emission scanning electron microscopy,and X-ray crystallography.The structural motifs of the framework materials vary from 2D to 3D,depending upon the axial ligation of the Sn(IV)porphyrin centers.Their photocatalytic performance was also investigated for the degradation of cationic methylene blue(MB),anionic amaranth dye(AM),and neutral bromocresol green(BCG)dyes in aqueous solutions under visible-light irradiation.The photocatalytic efficiency of 2 was higher than that of 1.The pseudofirst-order rate constants for the degradation of dyes by 1 were estimated to be 0.015 min^(−1)(MB),0.021 min^(−1)(AM),and 0.009 min^(−1)(BCG).In the case of 2,they were 0.020 min^(−1)(MB),0.031 min^(−1)(AM),and 0.011 min^(−1)(BCG).展开更多
Herein,the size-and shape-controlled synthesis of nearly-monodisperse,lanthanide-doped calcium fluoride(CaF_(2))nanocrystals(NCs)is reported.The sizes and shapes of CaF_(2)NCs are controlled by tailoring the reaction ...Herein,the size-and shape-controlled synthesis of nearly-monodisperse,lanthanide-doped calcium fluoride(CaF_(2))nanocrystals(NCs)is reported.The sizes and shapes of CaF_(2)NCs are controlled by tailoring the reaction conditions,such as the concentration of lithium fluoride precursors,reaction time and temperature,and the procedure for adding the calcium trifluoroacetate precursors in the reaction mixture.展开更多
Self-assembled peptides and proteins have turned out to be excellent templates for the growth of inorganic minerals and can be used to emulate natural biomineralization processes.Doing this,researchers have developed ...Self-assembled peptides and proteins have turned out to be excellent templates for the growth of inorganic minerals and can be used to emulate natural biomineralization processes.Doing this,researchers have developed complex sophisticated materials with properties,in some cases,similar to those found in nature.Of special interest is the development of scaffolds able to guide bone regeneration.The bone tissue comprises an organic matrix composed of aligned collagen fibers containing nanoapatite crystals oriented along the fiber direction.During bone mineralization,both processes,the self-assembly of collagen fibrils and mineralization occur simultaneously.Collagen fibers are able to control calcium phosphate nucleation and subsequent apatite crystal growth at a very limited range of collagen density and ionic concentration.In this study,we reproduced the simultaneity of both processes using an artificial peptide fluorenylmethoxycarbonyl-diphenylalanine(Fmoc-FF)that has the ability to self-assemble in water after the addition of Ca^(2+)ions.Therefore,the peptide self-assembly process and the mineralization of apatite are Ca-demanding processes and occur simultaneously.The role of peptide and ionic concentrations has been investigated affording organic/inorganic hybrid hydrogels with different degrees of homogeneity and mineralization.Interestingly,at very low Ca^(2+)concentrations,we found that apatite nanocrystals are integrated into Fmoc-FF fibrils and oriented as in biologically mineralized collagen fibrils,the basic building blocks of bone.展开更多
Fine-tuning the shape of nanostructured materials through easy and sustainable methods is a challenging task for green nanotechnology. In this contribution,we propose a cheap and green method capable of generating nan...Fine-tuning the shape of nanostructured materials through easy and sustainable methods is a challenging task for green nanotechnology. In this contribution,we propose a cheap and green method capable of generating nanoporous gold (gold foam). The proposed gold foams are fabricated by the self-assembly of gold nanowire networks in an eco-friendly solvent (water) and at room temperature. Our strategy allows a controlled growth process able to scale down the morphology of gold nanowire networks and the ultrastructure of the corresponding gold foams. The internal ultra-structure could be observed by conventional transmission electron microscopy by developing a method to embed a polymer resin in gold foam giving a composite material which can be cut into very thin slices (50 nm). We also demonstrate the potential applications and versatility of our method in terms of catalysis and very uniquely in terms of physical entrapment of materials (magnetic nanoparticles,thermo-labile molecules) without altering the ultrastructure of the gold-foam or the entrapped material.展开更多
基金Project (31100693/C100302) supported by the National Natural Science Foundation of ChinaProject (31011120049) supported by the Australia-China Special Fund, International Science Linkages Program co-supported by the Department of Innovation, Industry, Science and Research of Australia, and the Ministry of Science and Technology and National Science Foundation of China+1 种基金Project(2010ZDKG-96) supported by the Major Subject of "13115" Programs of Shaan’xi Province, ChinaProject (2012CB619102) supported by the National Basic Research Program of China
文摘The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functionalized solution for introducing the OH- and groups, and then the heparin was immobilized on the active TiO2 films through the electrostatic self assembly technology. It is shown that the heparinized films are mainly composed of anatase and rutile with smooth and dense surface. In vitro blood compatibility was evaluated by haemolysis test, clotting time and platelet adhesion behavior tests. The results show that the haemocompatibility of the alloy could be significantly improved by surface heparinization.
基金supported by Rachadapisek Sompote Fund for Postdoctoral Fellowship, Chulalongkorn University, Thailandthe Nanotechnology Center (NANOTEC), NSTDA Ministry of Science and Technology, Thailand, through its program of Center of Excellence Network+1 种基金National Research University Project of CHEthe Rachadapisek Sompote Endowment Fund (No. AM1041A)
文摘Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic acid）（PSS） and poly（diallyl-dimethylammonium chloride）（PDADMAC） to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue（MB）. Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.
基金Project supported by the Polish Ministry of Science and Higher Education (NN204 0317 33)
文摘The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1,5-pentanediami ne ligand(H2L) . It was obtained in situ in a one-step,metal-templated condensa tion of salicylaldehyde with 1,5-pentanediamine(cadaverine,biogenic polyamine) and characterized by microanalysis and spectroscopic(IR,ESI-MS,UV-Vis,and 1 H NMR) data. The [La(NO3) 3(μ-H2L) 2]∞ complex displayed 10-coordinate distorted bicapped dodecahedron geometry with unusual coordination pattern of undeprotonat ed salicylaldimines which acted as μ-bridging ditopic ligands using exclusivel y the oxygens as donor atoms with the nitrogen atoms not being involved in the c oordination environment.
基金the National High-tech Research and Development Program of China(''863''Program)(No.2012AA041402)National Natural Science Foundation of China(Nos.61175079and51105012)Fundamental Research Funds for the Central Universities (No.YWF-11-02-215)
文摘Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can drive on the ground, autonomously accomplish self-assembly and then fly in the air coordinately. Mechanical and electrical designs of a DSFR module, as well as the kinematics and dynamics analysis, are specifically investigated. Meanwhile, this paper brings forward a generalized adjacency matrix to describe configurations of DSFR structures. Also, the distributed flight control model is established for vertical taking-off and horizontal hovering, which can be applied to control of DSFR systems with arbitrary configurations. Finally, some experiments are carried out to testify and validate the DSFR design, the autonomous self-assembly strategy and the distributed flight control laws.
基金Projects(51102026,51272032) supported by the Program for the National Natural Science Foundation of ChinaProject(11A014) supported by the Scientific Research Fund of Hunan Provincial Education DepartmentProject supported by the Aid Program for Science and Technology Innovative Research Team in Higher Educational Instituions of Hunan Province,China
文摘The mesoporous Ti O2 has been synthesized by evaporation induced self assembly(EISA) method. The thermogravimetric/differential scanning calorimetric(TG/DSC), X-ray diffraction(XRD), high-resolution transmission electron microscopy(HR-TEM) and N2 adsorption desorption and adsorption are used to study the effects of the synthesized process condition on the microstructure of the as-synthesized mesoporous Ti O2. The photocatalytic performances of as-synthesized samples are evaluated by the degradation of the formaldehyde under ultraviolet light irradiations. The results demonstrate that the as-synthesized mesoporous Ti O2 are anatase with the uniform size about 20-40 nm. The sample is prepared using cetyltrimethyl ammonium bromide(CTAB) as the template with average pore size distribution of 8.12 nm, specific surface area of 68.47 m2/g and pore volume of 0.213 m L/g. The samples show decomposition of formaldehyde 95.8% under ultraviolet light irradiations for 90 min. These results provide a basic experimental process for preparation mesoporous Ti O2, which will posses a broad prospect in terms of the applications in improving indoor air quality.
基金Supported by the National Natural Science Foundation of China(Nos. 20476011 and 20371007).
文摘The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.
基金supported through Annual Research Grants Program (ARP-29-111) by King Abdulaziz City for Scienceand Technology (KACST)
文摘In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain ＇y-alumina in the nano scale. Scanning electron microscopy images of the prepared γ-alumina showed big and strong agglomeration of the nanoparticles indicating that these nanoparticles have strong surface forces. Transmission electron microscopy images confirmed that the γ-alumina nanoparticles 3-7 nm in size were converted to uniform spherical shape in the size range of 1-2 mm after shaking with dimethyl disulfide in the presence of n-hexane at room temperature. This phenomenon did not appear in the case of alumina in the micro scale. The surface properties of the prepared γ-alumina in the nano scale were characterized and compared with the γ-alumina in the micro scale by using low temperature nitrogen adsorption-desorption system, indicating that the specific surface area of the prepared γ-alumina nanoparticles is larger than that of the γ-alumina in the micro scale. Furthermore, micro- and meso-pores were observed for the if-alumina nanoparticles while only mesoporous structure was detected for the γ-alumina in the micro scale. These experimental results suggested that the self assembly behavior of the γ-alumina nanoparticles may be due to the selective adsorption ofdimethyl disulfide in the micropores of these nanoparticles to act as bridge linking the nanoparticles.
文摘Pepsin was assembled on the surface of prepared poly(ethylene terephthalate)(PET-NH3^+) substrates.The composition and structure of the pepsin/PET-NH3^+ assembling films in different condition were characterized by X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM).
基金support of the National Natural Science Foundation of China(22271044)Jilin Provincial Science and Technology Development Foundation(20210101404JC).
文摘Perfluorooctanoic acid-modified CsPbBr_(3) perovskite quantum dots(F-PQDs)are used as both luminescence centers and photocatalysts to prepare organic-inorganic nanohybrid assemblies.Polymerizationinduced self-assembly(PISA)technology of poly(poly(ethylene glycol)monomethyl ether methacrylate)-b-poly(perfluorooctyl)ethyl methacrylate copolymers(POEGMA-b-PFOEMA)via photo-induced electron/energy transfer RAFT(PET-RAFT)simplifies the synthetic steps of hybrid nanoparticles and enables the in situ encapsulation of PQDs through the dipole-dipole interaction based on the fluorocarbon chain on F-PQDs’surface and FOEMA.The insolubility of the PFOEMA block with liquid crystal properties allows for effective modulation of the hybrid nanostructure in toluene.Modulation of the block length achieves the transition from nanorods to spindle-like nano-assemblies and these hybrid nanoparticles possess PQDs’inherent fluorescence and enhanced stability.This strategy simplifies the preparation scheme of a PQD/polymer composite and provides a new perspective for the design of organic-inorganic hybrid materials through the photo-PISA strategy.
基金financially supported by the National Natural Science Foundation of China(No.21204002)Specialized Research Fund for the Doctoral Program of Higher Education(No.20111102120050)+1 种基金Program for New Century Excellent Talents in Universities(2010)the Fundamental Research Funds for the Central Universities
文摘pH-sensitive wettability of polystyrene-b-poly（4-vinylpyridine） （PS-b-P4VP） self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.
基金financial support from the National Natural Science Foundation of China(No.51771175)the Science Foundation of State Administration of market supervision(No.2021MK164)。
文摘Compared with noble metals, improving the sensitivity of semiconducting surface-enhanced Raman scattering(SERS) substrates is of great significance to their fundamental research and practical application of Raman spectroscopy. Herein, a simple chemical method is developed to synthesize a rhenium trioxide(ReO_(3)) microtubes assembled with highly crystalline nanoparticles. The ReO_(3) microtubes show a strong and well-defined surface plasmon resonance(SPR) behavior in visible region, which is rare for non-noble metals. As a low-cost SERS substrate, the plasmonic ReO_(3) microtubes exhibit a Raman enhancement factor of 8.9×10^(5) and a lowest detection limit of 1.0×10^(-9) mol/L for phenolic pollutants. Moreover, these ReO_(3) microtubule SERS substrates show excellent chemical stability and can resist the corrosion of strong acids and bases.
基金supported by the National Natural Science Foundation of China(21390394)the National Basic Research Program of China(2012CB821700 and 2011CB808703)+3 种基金NSFC(21261130584 and 91022030)the“111”project(B07016)an Award from the KAUST Project(CRG-1-2012-LAI-009)the Ministry of Education,Science and Technology Development Center Project(20120061130012).
文摘Novel three-dimensional(3D)foam-like porous carbon architectures with homogeneous N doping and unique mesopore-in-macropore structures have been fabricated from a metal–organic complex via a simple template-free solid state method,which have a high specific surface area(2732 m^(2)g^(−1)),large pore volume(3.31 cm^(3)g^(−1)),interconnected hierarchical pore structures with macro/meso/micro multimodal distribution and abundant surface functionality N doping(5.36 wt%).These characteristics give high catalytic performance for oxygen reduction with an onset potential of 0.98 V[versus reversible hydrogen electrode(RHE)]and a half-wave potential of 0.83 V(versus RHE)in alkaline media,which are comparable with those of the state-of-the-art platinum/carbon catalyst and many noble metal free catalysts.These results demonstrate the significant advantages of the unique mesopore-in-macropore porous structures with efficient heteroatom doping,which provides abundant accessible active sites for high mass and charge transports.The present work provides a new,simple and environmentally safe synthesis strategy for the preparation of 3D porous carbon architectures for use as efficient electrochemical energy devices and gives good insight into the fabrication of advanced nanostructured materials.
基金support of National Natural Science Foundation of China(Projects 21471071,21431002 and 31471233)the Fundamental Research Funds for the Central Universities(Project lzujbky-2017-Ot05,lzujbky-2018-Ot01,lzujbky-2015-k16 and lzujbky-2016-74).
文摘Nanohybrids have greatly promoted the application of nanomaterials in real world problems,since they not only present the individual advanced properties of each material,but can also realize the amplification of the functions of the combined materials.Here,we assembled up-conversion nanoparticles NaYF_(4),Yb/Er@NaYF_(4)(UCNPs)and MnFe_(2)O_(4)(MF)into a multi-functional nanohybrid through direct coordination using polyacrylic acid(PAA)as the surficial bridging linker.Afterwards,the photosensitizer molecules Rose Bengal(RB)and PEG-COOH were covalently grafted onto the nanohybrid.UCNPs effectively stimulated RB by means of fluorescence resonance energy transfer effects to convert O_(2) to 1O_(2).Meanwhile,the MF NPs worked as a Fenton catalyst to continuously generate O_(2) by decomposing H_(2)O_(2) in the H_(2)O_(2) over-expression tumor micro-environment.Thus,a comprehensive therapeutic system was successfully constructed,which can efficiently perform photodynamic therapy(PDT)of hypoxic tumors under the excitation of a 980 nm laser.This work explored a new method for the assembly of nanohybrids using heterogeneous nanomaterials by coordination with bridging ligands between NPs and provided a versatile PDT candidate for hypoxic tumors.
基金supported by the National Natural Science Foundation of China(22001034,22071045,21871026)the Open Fund of the Jiangxi Province Key Laboratory of Synthetic Chemistry(JXSC202008)the Research Found of the East China University of Technology(No.DHBK2019264,DHBK2019265,DHBK2019267).
文摘The reaction of UO_(2)(OAc)_(2) and Na_(9)[A-PW_(9)O_(34)]in solution with different pH values leads to the formation of two Keggin-type sandwich polyoxometalates,namely Na11H(H_(2)O)_(31)[Na(UO_(2))(A-PW_(9)O_(34))]_(2)·7H_(2)O(1)and Na_(12)(H_(2)O)_(29)[Na(UO_(2))(A-PW_(9)O_(34))]_(2)·7H_(2)O(2),which have been characterized by single-crystal X-ray diffraction,FT-IR spectroscopy,and PXRD techniques.Compounds 1 and 2 crystallize in similar conditions with different pH values and show similar sandwich crystal structures except that one extra Na(I)ion acts as a bridging linker in compound 2 than in 1.It is notable that 1 exhibits excellent catalytic activity for the synthesis of sulfonyl pyrazoles via the condensation and cyclization reaction of sulfonyl hydrazides with 1,3-diketones,and the yield of the desired product is up to 99%.This is the first report to investigate the catalytic properties of U-containing polyoxometalates.
基金supported by the National Natural Science Foundation of China(No.52176185)the Hubei Provincial Department of Education(grant no.D20201007).
文摘Lithium-sulfur batteries(LSBs)are broadly considered to be the most promising next-generation energy storage because of their ultrahigh theoretical energy density and cost-effectiveness.However,the“shuttle effect”and sluggish conversion kinetics of polysulfides severely hinder their practical application.To address these challenges,a unique Co-doped MnO_(2) nanorod network layer with oxygen vacancies(Co-MnO_(x))was devised by self-assembly on a commercial separator through the chemical growth method for high-performance LSBs.The Co-MnO_(x) modified separators(Co-MnO_(x)@PP)not only effectively alleviate the“shuttle effects”but also accelerate the redox conversion of polysulfides.More importantly,the Co-MnO_(x)@PP demonstrated superior thermostability and flame-retardant properties owing to the chemical growth method.The LSBs with Co-MnO_(x)@PP separators exhibited a high reversible capacity of 902.0 mA h g^(-1) and 562.2 mA h g^(-1) at 0.5 C for 20℃ and 60℃ after 200 cycles,respectively.Even at 3 C,after 500 cycles,a superb cycling performance of 715.2 mA h g^(-1) with an ultra-low decay of 0.069%for each cycle was achieved.Therefore,this proposed strategy of a Co-doped MnO_(2) nanorod network layer with oxygen vacancies will provide a new route for rationally devising durable and efficient LSBs.
基金supported by the research funds for the National Natural Science Foundation of China(21606081).
文摘MXene is a new 2D transition metal carbide possessing metallic conductivity and hydrophilic surfaces.It has drawn widespread attention as a potential material for electrode use.However,the applications of MXene are limited by its property of low electrical capacity.In this paper,a novel MnO_(2)/MXene composite is prepared by electrostatic self-assembly.Firstly,delaminated MnO_(2)nanosheets are obtained through the intercalation delamination of multilayered H-MnO_(2)in a cationic Gemini surfactant(Gem)solution,leading to a positively charged surface.Then,the positive MnO_(2)nanosheets are assembled on negative MXene nanosheets through electrostatic self-assembly to form a MnO_(2)/MXene composite.The characterization results show that the MnO_(2)nanosheets are intimately assembled on the MXene nanosheets.As an electrode material,the MnO_(2)/MXene composite displays a specific capacitance of 340 F g^(−1)at 1 A g^(−1),which is three times the performance of an MXene electrode.In addition,the MnO_(2)/MXene electrode shows a high retention rate(90.3%retention at 10 A g^(−1))and good cycling life(87.6%of the initial specific capacitance is retained after 2000 cycles at 4 A g^(−1)).The properties of the proposed composite are attributed to the excellent conductivity of MXene and the high specific capacitance of MnO_(2).
基金supported by the National Research Foundation of Korea(NRF)grant(no.2017R1A2B2011585)funded by the Korea government(MSIT).
文摘Two porphyrin-based coordination frameworks,[Ag_(2)(TPyP)Sn(OH)_(2)](NO_(3))_(2)·(solv)x(1)and[Ag_(2)(TPyP)Sn(INA)_(2)](OTf)_(2)·(CH_(3)CN)_(2)(2)(INA=isonicotinato anion,OTf=CF_(3)SO_(3)^(−)),were constructed by the selfassembly of hexacoordinated(meso-tetra-(4-pyridyl)porphyrinato)Sn(IV)building blocks with Ag(Ⅰ)ions.They were characterized using elemental analysis,UV-visible spectroscopy,fluorescence spectroscopy,FT-IR,field-emission scanning electron microscopy,and X-ray crystallography.The structural motifs of the framework materials vary from 2D to 3D,depending upon the axial ligation of the Sn(IV)porphyrin centers.Their photocatalytic performance was also investigated for the degradation of cationic methylene blue(MB),anionic amaranth dye(AM),and neutral bromocresol green(BCG)dyes in aqueous solutions under visible-light irradiation.The photocatalytic efficiency of 2 was higher than that of 1.The pseudofirst-order rate constants for the degradation of dyes by 1 were estimated to be 0.015 min^(−1)(MB),0.021 min^(−1)(AM),and 0.009 min^(−1)(BCG).In the case of 2,they were 0.020 min^(−1)(MB),0.031 min^(−1)(AM),and 0.011 min^(−1)(BCG).
基金supported by the Creative Materials Discovery Program through the National Research Foundation of Korea(NRF)grants funded by the Korean government(2018M3D1A1059001,2021M3H2A1038042,2021M3H4A3A01062960,2021R1A2C1013604,and 2022R1A4A2000776).
文摘Herein,the size-and shape-controlled synthesis of nearly-monodisperse,lanthanide-doped calcium fluoride(CaF_(2))nanocrystals(NCs)is reported.The sizes and shapes of CaF_(2)NCs are controlled by tailoring the reaction conditions,such as the concentration of lithium fluoride precursors,reaction time and temperature,and the procedure for adding the calcium trifluoroacetate precursors in the reaction mixture.
基金supported by projects RTI-2018-095794-A-C22,RYC-2016-21042 and project PID2020-118498GB-I00 funded by MCIN/AEI/1013039/501100011033 and projects P18-FR-3533 and P18-TP-0969 by FEDER/Junta de Andalucía-Consejería de Transformación Económica,Industria,Conocimiento y Universidades(Spain)+2 种基金Thanks go to the CIC personnel of the University of Granada for technical assistanceMCMT acknowledges grant PRE2018-083773 funded by MCIN/AEI/10.13039/501100011033FSE“El FSE invierte en tu futuro”,Spain,GBRR also acknowledges Junta de Andalucia for her postdoctoral contract within the PAIDI 2020 program(DOC_01383).
文摘Self-assembled peptides and proteins have turned out to be excellent templates for the growth of inorganic minerals and can be used to emulate natural biomineralization processes.Doing this,researchers have developed complex sophisticated materials with properties,in some cases,similar to those found in nature.Of special interest is the development of scaffolds able to guide bone regeneration.The bone tissue comprises an organic matrix composed of aligned collagen fibers containing nanoapatite crystals oriented along the fiber direction.During bone mineralization,both processes,the self-assembly of collagen fibrils and mineralization occur simultaneously.Collagen fibers are able to control calcium phosphate nucleation and subsequent apatite crystal growth at a very limited range of collagen density and ionic concentration.In this study,we reproduced the simultaneity of both processes using an artificial peptide fluorenylmethoxycarbonyl-diphenylalanine(Fmoc-FF)that has the ability to self-assemble in water after the addition of Ca^(2+)ions.Therefore,the peptide self-assembly process and the mineralization of apatite are Ca-demanding processes and occur simultaneously.The role of peptide and ionic concentrations has been investigated affording organic/inorganic hybrid hydrogels with different degrees of homogeneity and mineralization.Interestingly,at very low Ca^(2+)concentrations,we found that apatite nanocrystals are integrated into Fmoc-FF fibrils and oriented as in biologically mineralized collagen fibrils,the basic building blocks of bone.
文摘Fine-tuning the shape of nanostructured materials through easy and sustainable methods is a challenging task for green nanotechnology. In this contribution,we propose a cheap and green method capable of generating nanoporous gold (gold foam). The proposed gold foams are fabricated by the self-assembly of gold nanowire networks in an eco-friendly solvent (water) and at room temperature. Our strategy allows a controlled growth process able to scale down the morphology of gold nanowire networks and the ultrastructure of the corresponding gold foams. The internal ultra-structure could be observed by conventional transmission electron microscopy by developing a method to embed a polymer resin in gold foam giving a composite material which can be cut into very thin slices (50 nm). We also demonstrate the potential applications and versatility of our method in terms of catalysis and very uniquely in terms of physical entrapment of materials (magnetic nanoparticles,thermo-labile molecules) without altering the ultrastructure of the gold-foam or the entrapped material.
