To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results dur...To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.展开更多
Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them su...Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them suitable for preparing microspheres.Inorganic materials(mainly inorganic minerals)have excellent mechanical properties and are inexpensive and easy to obtain.Through the coupling and hybridization of natural polymers and inorganic materials,they can complement each other's advantages and synergistically enhance efficiency,resulting in many excellent physical and chemical properties.Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking,solution mixing,in-situ synthesis,extrusion,etc.The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects,is safe and non-toxic,and the cost of carrier materials is relatively low,which has certain significance for the development of new drug carriers.This article reviews the recent research on the preparation,drug loading and release properties of inorganic material/natural polymer composite microspheres,analyzes the advantages and disadvantages of commonly used preparation methods,and looks forward to the development direction of composite microspheres.展开更多
Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer (PLAA) with D, L-lacti...Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer (PLAA) with D, L-lactide (D, L-LA) and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.展开更多
Using the technique of microemulsion polymerization with nano-reactor, dysprosium ferrite/polyacrylamide magnetic composite microsphere was prepared by one-step method in a single inverse microemulsion. The structure,...Using the technique of microemulsion polymerization with nano-reactor, dysprosium ferrite/polyacrylamide magnetic composite microsphere was prepared by one-step method in a single inverse microemulsion. The structure, average particle size, morphology of composite microsphere were characterized by FTIR, XRD, TEM and TGA. The magnetic responsibility of composite microsphere was also investigated. The results indicate that the magnetic composite microsphere possess high magnetic responsibility and suspension stability.展开更多
Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on ...Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.展开更多
Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were co...Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the binder.The influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation performance.The results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size uniformity.The microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good dispersibility.The ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems.展开更多
Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to ...Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to control drugs releases.Electrospray has been proven an effective technique to prepare MS with uniform particle size and high drug-loading rate.In this study,we applied electrospray to simply and hierarchically fabricate sphere-in-sphere composite microspheres,with smaller poly(lactic-co-glycolic acid)MS(~8-10 lm in diameter)embedded in a larger chitosan MS(~250-300 lm in diameter).The scanning electron microscopy images revealed highly uniform MS that can be accurately controlled by adjusting the nozzle diameter or voltage.Two kinds of model drugs,bovine serum albumin and chlorhexidine acetate,were encapsulated in the microspheres.The fluorescence-labeled rhodamine-fluoresceine isothiocyanate(Rho-FITC)and ultraviolet(UV)spectrophotometry results suggested that loaded drugs got excellent distribution in microspheres,as well as sustained,slow release in vitro.In addition,far-UV circular dichroism and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS)results indicated original secondary structure and molecular weight of drugs after electrospraying.Generally speaking,our research proposed a modified hierarchically electrospraying technique to prepare sphere-in-sphere composite MS with two different drugs loaded,which could be applied in sequential,multi-modality therapy.展开更多
The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking ad...The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking advantages of the synergistic effects of the activated Si nanoparticles and conductive flower-like MXene microspheres with ample ion-diffusion pathways. Consequently,the intrinsic MXene nanosheets with intelligently regulated interlayer spacing can accommodate the volume change induced strain during cycling, and the strong interaction between the Si and MXene matrix greatly contributes to the robust structural stability. As expected, the Si/MXene composite architecture exhibits boosted sodium storage performance, in terms of an inspiring reversible capacity of 751 mAh·g^(-1)at 0.1 A·g^(-1), remarkable long-term cycling stability of 376 mAh·g^(-1)at 0.1 A·g^(-1) over 500 cycles, and outstanding rate capability(after one consecutive current density changing from 0.1 to 2.0 A·g^(-1), a large capacity of 275 mAh·g^(-1) is regained after suddenly returning the initial current density back to 0.1 A·g^(-1) and in the subsequent 200 cycles this composite architecture anode still delivers a capacity of 332 mAh·g^(-1)). The kinetics analysis indicates superior pseudocapacitive property, high electronic conductivity, and favorable sodium-ion adsorption and diffusion capability,confirming fast sodium storage performance. Impressively, ex-situ X-ray diffraction and selected area electron diffraction characterizations corroborate the formation of NaSi;as the main sodiation products during the reversible evolutions of cycled proceeding with sodium-ion insertion. This work sheds light on the elaborate design of silicon-based nanostructured anodes towards advanced high-performance sodium-ion batteries.展开更多
A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum ...A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment analysis.The GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release study.The results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in GPcM.The GPcM have a uniform particle size ranging from 395.1μm to 841.5μm.The drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,respectively.The bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 h.The results suggested that the GPcM may have potential application value in drug sustained and controlled release system.展开更多
Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeabil...Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability,which will lead to the distortion of the petroleum resources reserves assessment.Therefore,the hollow glass microspheres/epoxy resin(HGM/EP)composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring(ITP-Coring),and the physical,mechanical,and temperature preserved properties were evaluated.The results indicated that:As the HGM content increased,the density and mechanical properties of the composites gradually decreased,while the water absorption was deficient without hydrostatic pressure.For composites with 50 vol%HGM,when the hydrostatic pressure reached 60 MPa,the water absorption was above 30.19%,and the physical and mechanical properties of composites were weakened.When the hydrostatic pressure was lower than 40 MPa,the mechanical properties and thermal conductivity of composites were almost unchanged.Therefore,the composites with 50 vol%HGM can be used for ITPCoring operations in deep environments with the highest hydrostatic pressure of 40 MPa.Finally,to further understand the temperature preserved performance of composites in practical applications,the temperature preserved properties were measured.An unsteady-state heat transfer model was established based on the test results,then the theoretical change of the core temperature during the coring process was obtained.The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.展开更多
Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and ...Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and achieving fully accepted mechanism also have not been solved.Herein,the commensal composite microspheres withα-MnO_(2) nano-wires and carbon nanotubes were achieved and could effectively suppress ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O rampant crystallization.The electrode assembled with the microspheres delivered a high initial capacity at a current density of 0.05 A g^(-1) and maintained a significantly prominent capacity retention of 88%over 2500 cycles.Furthermore,a novel energy-storage mechanism,in which multivalent manganese oxides play a synergistic effect,was comprehen-sively investigated by the quantitative and qualitative analysis for ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O.The capacity contribution of multivalent manganese oxides and the crystal structure dissection in the transformed processes were completely identified.Therefore,our research could provide a novel strategy for designing improved electrode structure and a comprehensive understanding of the energy storage mechanism of α-MnO_(2) cathodes.展开更多
Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PSt-co-PAMPS) and poly(methylmethacrylate)-co-poly(glycidyl methacrylate) (PMMA-co-PGMA) microspheres with mean size of...Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PSt-co-PAMPS) and poly(methylmethacrylate)-co-poly(glycidyl methacrylate) (PMMA-co-PGMA) microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin (BSA) by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.展开更多
Hollow structure microspheres with composite polymeric-Laponite shells were prepared by electrostatic self-assembly of Laponite on the polymeric hollow microspheres in this work.The multilayer hydrophilic core/hydroph...Hollow structure microspheres with composite polymeric-Laponite shells were prepared by electrostatic self-assembly of Laponite on the polymeric hollow microspheres in this work.The multilayer hydrophilic core/hydrophobic shell polymer latex particles containing carboxyl groups inside were first synthesized via seeded emulsion polymerization,followed by alkali treatment,generating polymeric hollow microspheres.Then,polyethyleneimine(PEI) and Laponite were alternately electrostatic adsorbed on the prepared polymeric hollow microspheres to form polymeric-Laponite composite hollow microspheres.It was indicated that the morphology of alkali-treated microspheres could be tuned through simply altering the dosage of alkali used in the post-treatment process.Along with the increasing of the coating layers,the zeta potential of microspheres absorbed PEI or Laponite approximately tended to be constant respectively,and the thickness of Laponite layer around the hollow microspheres increased clearly,getting more uniform and homogenous.Furthermore,the corresponding polymeric-Laponite hollow microspheres showed high pressure resistance ability compared to the polymeric hollow microspheres.展开更多
A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe3O4 nanoparticles in PA6 domains of polystyrene (PS)...A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe3O4 nanoparticles in PA6 domains of polystyrene (PS)/polyamide 6 (PA6) immiscible blends. The morphology of PA6/Fe3O4 composite magnetic mierospheres was studied by scanning electronic microscopy (SEM). The composite magnetic mierospheres were spherical with a diameter range of 0.5-8 μm; the diameter was sharply decreased with a very narrow distribution by adding terminal maleic anhydride fimctionalized polystyrenes (FPS) for reactive blending. Transmission electron microscopy (TEM) and thermogravimetry analysis (TGA) results showed that most of Fe3O4 was located in the PA6 microspheres. Magnetization data revealed the magnetite content of PA6/Fe3O4 microspheres was about 32 wt% and the saturation magnetization could be up to 17.2 AmE/kg.展开更多
Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for n...Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for nanostructure are complicated,low-efficient and underperform for wide-scale applications.Herein,a novel hierarchical framework of hollow Ni/NiFe2O4-CNTs compositemicrosphere forcibly-assembled by zero-dimensional(OD)Ni/NiFo204 nanoparticle(<16 nm)and one-dimensional(1D)self-supporting CNTs was fabricated successfully.Benefitted from the unique nanostructure,such monohybrids can achieve remarkable oxygen evolution reaction(OER)performance in alkaline media with a low overpotential and superior durability,which exceeds most of the commercial catalysts based on IrO/RuO2 or other non-noble metal nanomaterials.The enhanced OER performance of Ni/NiFe2OA-CNTs composite is mainly ascribed to the increased catalytic activity and the optimized conductivity induced by the effects of strong hierarchical coupling and charge transfers between CNTs and Ni/NiFe204 nanoparticles.These effects are greatly boosted by the polarized heterojunction interfaces confirmed by electron holography.The density functional theory(DFT)calculation indicates the epitaxial Ni further enriches the intrinsic electrons contents of NiFe204 and thus accelerates absorption/desorption kinetics of OER intermediates.This work hereby paves a facile route to construct the hollow composite microsphere with excellent OER electrocatalytic activity based on non-noble metal oxide/CNTs.展开更多
The fabrication of raspberry-like poly(ethylene terephthalate)/polyacrylonitrile(PET/PAN) microspheres by g-ray radiation-induced polymerization of acrylonitrile on micron-sized PET microspheres were first reporte...The fabrication of raspberry-like poly(ethylene terephthalate)/polyacrylonitrile(PET/PAN) microspheres by g-ray radiation-induced polymerization of acrylonitrile on micron-sized PET microspheres were first reported in this work. A PET emulsion was firstly prepared by dispersing a PET solution with 1,1,2,2-tetrachloroethane/phenol mixture as the solvent into an aqueous solution of sodium dodecyl sulfate.Then, PET microspheres were formed by precipitating the PET emulsion droplets from ethanol. The influence of the PET solvent and the weight ratio of ethanol to PET emulsion on the morphology of the PET microspheres had been investigated. After the surface of the prepared PET microspheres was grafted with poly(acrylic acid), the grafting polymerization of AN also had been successfully initiated by g-ray radiation to form PAN microspheres with a size of about 100 nm on the PET microspheres. This work provides a new method to fabricate micron-sized PET microspheres, and further expands the functionalization of PET and its application fields.展开更多
基金National Natural Science Foundation of China(No.2275150)。
文摘To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.
文摘Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them suitable for preparing microspheres.Inorganic materials(mainly inorganic minerals)have excellent mechanical properties and are inexpensive and easy to obtain.Through the coupling and hybridization of natural polymers and inorganic materials,they can complement each other's advantages and synergistically enhance efficiency,resulting in many excellent physical and chemical properties.Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking,solution mixing,in-situ synthesis,extrusion,etc.The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects,is safe and non-toxic,and the cost of carrier materials is relatively low,which has certain significance for the development of new drug carriers.This article reviews the recent research on the preparation,drug loading and release properties of inorganic material/natural polymer composite microspheres,analyzes the advantages and disadvantages of commonly used preparation methods,and looks forward to the development direction of composite microspheres.
基金Project (21107032) supported by the National Natural Science Foundation of ChinaProjects (Y406469,Y4110606) supported by Natural Science Foundation of Zhejiang Province, China+1 种基金Projects (2008AY2018,2011AY1048-5,2011AY1030) supported by the Science Foundation of Jiaxing Science and Technology Bureau,ChinaProject (2009C21003) supported by Science and Technology Department of Zhejiang Province,China
文摘Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer (PLAA) with D, L-lactide (D, L-LA) and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.
文摘Using the technique of microemulsion polymerization with nano-reactor, dysprosium ferrite/polyacrylamide magnetic composite microsphere was prepared by one-step method in a single inverse microemulsion. The structure, average particle size, morphology of composite microsphere were characterized by FTIR, XRD, TEM and TGA. The magnetic responsibility of composite microsphere was also investigated. The results indicate that the magnetic composite microsphere possess high magnetic responsibility and suspension stability.
基金Supported by the National Natural Science Foundation of China(No. 2 99730 2 6 and 2 0 0 75 0 2 8) ,K.C.Wang Post-Doctoral Research Award Fund of Chinese Academ y of Sciences,and China Postdoctoral Science Foundation
文摘Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.
基金supported by National Natural Science Foundation of China(grant No.22005275).
文摘Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the binder.The influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation performance.The results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size uniformity.The microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good dispersibility.The ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems.
基金supported by National Natural Science Foundation of China(nos.31771056,81671827 and 51572144).
文摘Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to control drugs releases.Electrospray has been proven an effective technique to prepare MS with uniform particle size and high drug-loading rate.In this study,we applied electrospray to simply and hierarchically fabricate sphere-in-sphere composite microspheres,with smaller poly(lactic-co-glycolic acid)MS(~8-10 lm in diameter)embedded in a larger chitosan MS(~250-300 lm in diameter).The scanning electron microscopy images revealed highly uniform MS that can be accurately controlled by adjusting the nozzle diameter or voltage.Two kinds of model drugs,bovine serum albumin and chlorhexidine acetate,were encapsulated in the microspheres.The fluorescence-labeled rhodamine-fluoresceine isothiocyanate(Rho-FITC)and ultraviolet(UV)spectrophotometry results suggested that loaded drugs got excellent distribution in microspheres,as well as sustained,slow release in vitro.In addition,far-UV circular dichroism and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS)results indicated original secondary structure and molecular weight of drugs after electrospraying.Generally speaking,our research proposed a modified hierarchically electrospraying technique to prepare sphere-in-sphere composite MS with two different drugs loaded,which could be applied in sequential,multi-modality therapy.
基金the National Natural Science Foundation of China(No.21703209)Shanxi Province Science Foundation(No.201901D211270)+1 种基金Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi,Key Research and Development(R&D)Projects of Shanxi Province(No.201803D121037)the Specialized Research Fund for Sanjin Scholars Program of Shanxi Province and the Graduate Student Education Innovation Projects of Shanxi Province。
文摘The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking advantages of the synergistic effects of the activated Si nanoparticles and conductive flower-like MXene microspheres with ample ion-diffusion pathways. Consequently,the intrinsic MXene nanosheets with intelligently regulated interlayer spacing can accommodate the volume change induced strain during cycling, and the strong interaction between the Si and MXene matrix greatly contributes to the robust structural stability. As expected, the Si/MXene composite architecture exhibits boosted sodium storage performance, in terms of an inspiring reversible capacity of 751 mAh·g^(-1)at 0.1 A·g^(-1), remarkable long-term cycling stability of 376 mAh·g^(-1)at 0.1 A·g^(-1) over 500 cycles, and outstanding rate capability(after one consecutive current density changing from 0.1 to 2.0 A·g^(-1), a large capacity of 275 mAh·g^(-1) is regained after suddenly returning the initial current density back to 0.1 A·g^(-1) and in the subsequent 200 cycles this composite architecture anode still delivers a capacity of 332 mAh·g^(-1)). The kinetics analysis indicates superior pseudocapacitive property, high electronic conductivity, and favorable sodium-ion adsorption and diffusion capability,confirming fast sodium storage performance. Impressively, ex-situ X-ray diffraction and selected area electron diffraction characterizations corroborate the formation of NaSi;as the main sodiation products during the reversible evolutions of cycled proceeding with sodium-ion insertion. This work sheds light on the elaborate design of silicon-based nanostructured anodes towards advanced high-performance sodium-ion batteries.
基金by National Natural Science Foundation of China(81560737,31860250)Natural Science Foundation of Gansu Province(18JR3RA148)+1 种基金Guangxi Provincial Natural Science Fund of China(2016GXNSFAA380234)Fundamental Research Funds for Key Laboratory of Drug Screening and Deep Processing for Traditional Chinese and Tibetan Medicine of Gansu Province(20180801).
文摘A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment analysis.The GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release study.The results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in GPcM.The GPcM have a uniform particle size ranging from 395.1μm to 841.5μm.The drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,respectively.The bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 h.The results suggested that the GPcM may have potential application value in drug sustained and controlled release system.
基金National Natural Science Foundation of China(grant number 51827901)funded by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams(No.2019ZT08G315)Shenzhen Basic Research Program(General Program)(No.JCYJ20190808153416970)
文摘Deep petroleum resources are in a high-temperature environment.However,the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability,which will lead to the distortion of the petroleum resources reserves assessment.Therefore,the hollow glass microspheres/epoxy resin(HGM/EP)composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring(ITP-Coring),and the physical,mechanical,and temperature preserved properties were evaluated.The results indicated that:As the HGM content increased,the density and mechanical properties of the composites gradually decreased,while the water absorption was deficient without hydrostatic pressure.For composites with 50 vol%HGM,when the hydrostatic pressure reached 60 MPa,the water absorption was above 30.19%,and the physical and mechanical properties of composites were weakened.When the hydrostatic pressure was lower than 40 MPa,the mechanical properties and thermal conductivity of composites were almost unchanged.Therefore,the composites with 50 vol%HGM can be used for ITPCoring operations in deep environments with the highest hydrostatic pressure of 40 MPa.Finally,to further understand the temperature preserved performance of composites in practical applications,the temperature preserved properties were measured.An unsteady-state heat transfer model was established based on the test results,then the theoretical change of the core temperature during the coring process was obtained.The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.
基金This work is supported by the National Nature Science Foundation of China(51972108,52171200)Changsha Special Project(kh2301006)the Education Department of Hunan Province(19C0576).
文摘Aqueous zinc-ion batteries have been regarded as the most potential candidate to substitute lithium-ion batteries.However,many serious challenges such as suppressing zinc dendrite growth and undesirable reactions,and achieving fully accepted mechanism also have not been solved.Herein,the commensal composite microspheres withα-MnO_(2) nano-wires and carbon nanotubes were achieved and could effectively suppress ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O rampant crystallization.The electrode assembled with the microspheres delivered a high initial capacity at a current density of 0.05 A g^(-1) and maintained a significantly prominent capacity retention of 88%over 2500 cycles.Furthermore,a novel energy-storage mechanism,in which multivalent manganese oxides play a synergistic effect,was comprehen-sively investigated by the quantitative and qualitative analysis for ZnSO_(4)·3Zn(OH)_(2)·nH_(2)O.The capacity contribution of multivalent manganese oxides and the crystal structure dissection in the transformed processes were completely identified.Therefore,our research could provide a novel strategy for designing improved electrode structure and a comprehensive understanding of the energy storage mechanism of α-MnO_(2) cathodes.
基金Funded by the National Natural Science Foundation of China (20876070)Technology Innovation Team of Universities Funded Project of Jiangsu Province (2007-5)
文摘Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PSt-co-PAMPS) and poly(methylmethacrylate)-co-poly(glycidyl methacrylate) (PMMA-co-PGMA) microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles. The structures, morphologies, diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07 emu/g, respectively. The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin (BSA) by physical interaction and covalent interaction respectively. The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min, while on PSt-co-PAMPS microspheres was 59.62 mg/g microspheres in 120 min.
基金supported by Heilongjiang Provincial Natural Science Foundation for Youth, China (No. QC2014C052)Fund of Key Laboratory of Advanced materials of Ministry of Education (No. 2016AML06)the training project for innovation and entrepreneurship of the Harbin University of Science and Technology, China (2016)
文摘Hollow structure microspheres with composite polymeric-Laponite shells were prepared by electrostatic self-assembly of Laponite on the polymeric hollow microspheres in this work.The multilayer hydrophilic core/hydrophobic shell polymer latex particles containing carboxyl groups inside were first synthesized via seeded emulsion polymerization,followed by alkali treatment,generating polymeric hollow microspheres.Then,polyethyleneimine(PEI) and Laponite were alternately electrostatic adsorbed on the prepared polymeric hollow microspheres to form polymeric-Laponite composite hollow microspheres.It was indicated that the morphology of alkali-treated microspheres could be tuned through simply altering the dosage of alkali used in the post-treatment process.Along with the increasing of the coating layers,the zeta potential of microspheres absorbed PEI or Laponite approximately tended to be constant respectively,and the thickness of Laponite layer around the hollow microspheres increased clearly,getting more uniform and homogenous.Furthermore,the corresponding polymeric-Laponite hollow microspheres showed high pressure resistance ability compared to the polymeric hollow microspheres.
基金financially supported by the National Natural Science Foundation of China(Nos.50873033,20974033)
文摘A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe3O4 nanoparticles in PA6 domains of polystyrene (PS)/polyamide 6 (PA6) immiscible blends. The morphology of PA6/Fe3O4 composite magnetic mierospheres was studied by scanning electronic microscopy (SEM). The composite magnetic mierospheres were spherical with a diameter range of 0.5-8 μm; the diameter was sharply decreased with a very narrow distribution by adding terminal maleic anhydride fimctionalized polystyrenes (FPS) for reactive blending. Transmission electron microscopy (TEM) and thermogravimetry analysis (TGA) results showed that most of Fe3O4 was located in the PA6 microspheres. Magnetization data revealed the magnetite content of PA6/Fe3O4 microspheres was about 32 wt% and the saturation magnetization could be up to 17.2 AmE/kg.
基金This work was supported by the Ministry of Science and Technology of China(973 Project)(No.2018YFA0209102)the National Natural Science Foundation of China(Nos.11727807,51725101,51672050,and 61790581)。
文摘Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for nanostructure are complicated,low-efficient and underperform for wide-scale applications.Herein,a novel hierarchical framework of hollow Ni/NiFe2O4-CNTs compositemicrosphere forcibly-assembled by zero-dimensional(OD)Ni/NiFo204 nanoparticle(<16 nm)and one-dimensional(1D)self-supporting CNTs was fabricated successfully.Benefitted from the unique nanostructure,such monohybrids can achieve remarkable oxygen evolution reaction(OER)performance in alkaline media with a low overpotential and superior durability,which exceeds most of the commercial catalysts based on IrO/RuO2 or other non-noble metal nanomaterials.The enhanced OER performance of Ni/NiFe2OA-CNTs composite is mainly ascribed to the increased catalytic activity and the optimized conductivity induced by the effects of strong hierarchical coupling and charge transfers between CNTs and Ni/NiFe204 nanoparticles.These effects are greatly boosted by the polarized heterojunction interfaces confirmed by electron holography.The density functional theory(DFT)calculation indicates the epitaxial Ni further enriches the intrinsic electrons contents of NiFe204 and thus accelerates absorption/desorption kinetics of OER intermediates.This work hereby paves a facile route to construct the hollow composite microsphere with excellent OER electrocatalytic activity based on non-noble metal oxide/CNTs.
基金the National Natural Science Foundation of China (Nos. 51573174, 51473172, 51173175, 51073146 and 51103143)Foshan Scientific and Technological Innovation Team Project (No. 2013IT100041)the Fundamental Research Funds for the Central Universities (Nos. WK2060200012 and WK3450000001)
文摘The fabrication of raspberry-like poly(ethylene terephthalate)/polyacrylonitrile(PET/PAN) microspheres by g-ray radiation-induced polymerization of acrylonitrile on micron-sized PET microspheres were first reported in this work. A PET emulsion was firstly prepared by dispersing a PET solution with 1,1,2,2-tetrachloroethane/phenol mixture as the solvent into an aqueous solution of sodium dodecyl sulfate.Then, PET microspheres were formed by precipitating the PET emulsion droplets from ethanol. The influence of the PET solvent and the weight ratio of ethanol to PET emulsion on the morphology of the PET microspheres had been investigated. After the surface of the prepared PET microspheres was grafted with poly(acrylic acid), the grafting polymerization of AN also had been successfully initiated by g-ray radiation to form PAN microspheres with a size of about 100 nm on the PET microspheres. This work provides a new method to fabricate micron-sized PET microspheres, and further expands the functionalization of PET and its application fields.