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73 results about "Ostwald ripening" patented technology

Ostwald ripening is a phenomenon observed in solid solutions or liquid sols that describes the change of an inhomogeneous structure over time, i.e., small crystals or sol particles dissolve, and redeposit onto larger crystals or sol particles.

Tri-metal nano particle with asymmetric structure, preparation method and application thereof

The invention discloses a tri-metal nano particle with an asymmetric structure, a preparation method and application thereof. The preparation method comprises the steps: utilizing a golden rod as a seed and a silver nitrate solution as a metal precursor, utilizing a seed growing method to prepare rod-like template nano particles with core-shell structures and with silver coated outside the golden rod, centrifugally dispersing the particles in ultrapure water; utilizing a modified electric displacement reaction and a common reduction reaction, adding chloropalladic acid to the obtained aqueous solution containing template nano particles, utilizing ascorbic acid as a reducing agent and standing at room temperature; adjusting the molar ratio of silver nitrate and chloropalladic acid and the amount of surfactant and ascorbic acid, and obtaining dandelion-shaped nano particles under the action of Oswald ripening effect, wherein the brace is of a golden rod structure; one end of the golden rod is coated with spherical silver-palladium alloy with a branch-like structure and the other end is a pure golden rod. In the organic reaction using palladium as a catalyst, the palladium can be used as the catalyst with good activity and can be used as the tracking and detection for Raman spectrum signals.
Owner:SUZHOU UNIV

Synthesis method of superfine nanorod-baculariate SnO2 nano-materials

The invention relates to a synthesis method of superfine nanorod-baculariate SnO2 nano-materials, which belongs to the technical field of materials. According to invention, technically, by taking simple water-alcohol which is a mixed solution friendly to the environment and human bodies as a solvent, a superfine nanorod-baculariate SnO2 one-dimensional nano-material is synthesized by using a hydrothermal reaction, and in the process of reaction, any toxic, harmful and volatile organic solvents such as acids, alkalis, surfactants, molding templates, catalysts and the like are not added as auxiliary solvents, therefore, the method has the characteristics of environmental friendliness, and harmlessness to the human body; and the principle of the method is implemented by that parameters such as the volume fraction of the water-alcohol, the concentration of a precursor solution, and the like are adjusted so as to form specific thermodynamic reaction conditions, and then a SnO2 nanocrystal, according to the self growth rule of the nanocrystal, and through a synergistic action process of an Ostwald ripening mechanism and directional assembling, generates a SnO2 nanorod one-dimensional nano-structured crystal. A superfine nanorod-baculariate SnO2 nano-material prepared according to the invention has good sensitivity to isopropyl alcohol, ethanol, acetone, methanol and formaldehyde gas, and according to the method, gas sensors can be manufactured.
Owner:YUNNAN UNIV

Method for purifying ultrafine silver nanowires

The invention provides a method for purifying ultrafine silver nanowires. The method comprises the following steps that firstly, the unpurified ultrafine silver nanowires are prepared; and secondly, the unpurified ultrafine silver nanowires prepared in the step 1 are taken and washed with a solvent, then the unpurified ultrafine silver nanowires are dissolved through a solvent, then aqueous ammonia is dropped in, still standing is conducted, bottom precipitate is removed, and thus a purified ultrafine silver nanowire solution is obtained. The aqueous ammonia is added to the unpurified ultrafine silver nanowire solution, Ostwald ripening of silver nanoparticles in the unpurified ultrafine silver nanowire solution is assisted by the aqueous ammonia, growth of the silver nanoparticles is induced, and then the grown silver nanoparticles can be separated from the silver nanowires through a still standing process without other complicated purifying processes, and the ultrafine silver nanowires with the mass percent being 60% to 85% and the diameter being 20 nm to 30 nm are obtained.
Owner:SHAANXI COAL & CHEM TECH INST +1

Microfluid reactor based nano-particle preparation and particle controlled preparation process

The invention discloses a microfluid reactor based nano-particle preparation and a particle controlled preparation process. The particle controlled preparation process is characterized in that technological parameters of particles in different generation steps are regulated and controlled in a nanoliter or smaller scale by a microfluid control technology, particles quickly mix and react to form cores on line, evenly grow up and are quenched to stop growing at low temperature so as to regulate and control the size, the shape, the crystal structure and the surface performance of the particles on line, and the hierarchical structure of the particles can be regulated and controlled. The method effectively inhibits widened size distribution and crystal lattice defect caused by Ostwald ripening and directional binding during nano-particle formation. Compared with a tank stirred reactor which is unable to respectively control the technological parameters of nano-particles in different generation steps, the microfluid reactor can increase the stability of the crystal structure and the physical performance of the particles, and the structure and the performance at least can be stabilized above three months to one year according to the types of the particles. The nano-particle output of the process can reach above 300ml/hour, and the process is an environment-friendly type nano-material continuous scale production process.
Owner:宋玉军

Method for preparing two-dimensional ordered mesoporous nanosheet by inorganic salt interface induced assembling

ActiveCN110127661AImprove bindingPromotes slow nucleationMaterial nanotechnologySilicaFiltrationSolvent
The invention belongs to the technical field of nanoporous materials, and concretely relates to a method for preparing a two-dimensional ordered mesoporous nanosheet by inorganic salt interface induced assembling. The method comprises the following steps: uniform diffusion and transfer of a target precursor solution in the crystal interface of an inorganic salt are achieved by vacuum suction filtration or low-speed centrifugation with the soluble inorganic salt as a substrate and an amphiphilic block copolymer as a template; a highly ordered monolayer mesoporous structure is formed by a solvent volatilization induced co-assembling technology; and gradient temperature-controlled Ostwald ripening promotes organic solvent volatilization and induces molding, and the template is removed under the protection of N2 to obtain the highly ordered monolayer two-dimensional mesoporous nanosheet material. The assembled nanosheet material has a large pore size and regular and ordered spherical porechannels; and the type of the precursor can be changed to synthesize a plurality of mesoporous metal oxides, metal simple substances and inorganic nonmetal nanosheets. The method of the invention hasthe advantages of simplicity, easily available raw material, universality to nanomaterials, and suitableness for amplified production.
Owner:FUDAN UNIV

Preparation method for carboxyl and polypeptide modified AIE polymer nanoparticle

ActiveCN110156923AModulating abilityTuning particle characteristicsLuminescent compositionsFunctional monomerOil phase
The invention provides a preparation method for a carboxyl and polypeptide modified AIE polymer nanoparticle. The preparation method comprises the following steps: 1) preparing an emulsifier aqueous solution; 2) dissolving an AIE molecule, an Ostwald ripening effect inhibitor and an oil-soluble initiator into a mixed solution of a carboxyl functional monomer and a hydrophobic monomer so as to obtain an oil-phase solution; 3) adding the emulsifier aqueous solution into the oil-phase solution, carrying out pre-emulsification under stirring so as to obtain a crude emulsion, carrying out ultrasonic treatment so as to prepare a monomer fine emulsion, and introducing nitrogen to remove oxygen so as to prepare a carboxyl modified AIE polymer nanoparticle emulsion; 4) dissolving a carbodiimide condensing agent into an acidic pH buffer solution, adding an obtained solution into the emulsion prepared in the step 3), and carrying out an activation reaction; 5) dissolving omega-aminomaleimide intoan alkaline pH buffer solution; 6) adding an omega-aminomaleimide solution into an emulsion prepared in the step 4), and carrying out a reaction; and 7) adding a polypeptide aqueous solution with theterminal containing a cysteine sequence unit into an emulsion prepared in the step 6), and carrying out a reaction so as to prepare the carboxyl and polypeptide modified AIE polymer nanoparticle.
Owner:ZHEJIANG SCI-TECH UNIV

Three-dimensional hollow titanium dioxide assembled from (001) surfaces, and preparation method and application thereof

InactiveCN105133013AEffective control of the hydrolysis processPromote selective growthMaterial nanotechnologyPolycrystalline material growthMicro nanoDischarge efficiency
The invention discloses a three-dimensional hollow titanium dioxide assembled from (001) surfaces, and a preparation method and application thereof. The three-dimensional hollow titanium dioxide can be applied to the field of manufacturing of positive electrode materials of lithium batteries. According to the invention, a hydro-thermal method is employed for preparation of titanium dioxide, and under the co-action of hydrofluoric acid and hydrogen peroxide, the hydrolysis process of a reaction intermediate peroxotitanic acid is effectively regulated and controlled. The formation process of a hollow structure is related to an Ostwald ripening mechanism, fluoride ions promote preferential growth of a crystal along [001] direction, and finally, the three-dimensional hollow product is formed. The method has the advantages of low cost, simple and controllable process, mild reaction, obtainment of the pure product and a high exposure rate of the (001) surfaces; and the titanium dioxide material prepared by using the method has the high-exposure (001) surfaces, is of a hollow micro-nano structure, can be applied to preparation of positive pole pieces of the lithium battery, shortens a diffusion path of lithium ions, facilitates intercalation/deintercalation behavior of lithium ions and alleviates volume expansion of the material during charging and discharging, and thus, the lithium battery has improved charging and discharging efficiency and prolonged cycle life.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE

Vanadium nitride material and preparation method and application thereof

The invention relates to a vanadium nitride material. The vanadium nitride material is assembled from porous vanadium nitride nanosheets and is in a spherical structure. The spherical structure comprises hollow cavities formed by the porous vanadium nitride nanosheets through separation. A vanadate solution and a zinc salt solution are mixed according to certain proportion, Zn3(OH)2(V2O7)(H2O)2 is obtained thorough Ostwald ripening, and the vanadium nitride material is obtained after reduction and nitration. The obtained vanadium nitride material has a multi-level micro-nano structure, the pore size distribution is even and reasonable, the specific surface area is up to 18-50 m<2> / g, the vanadium nitride material is good in dispersity, and is an excellent catalyst carrier. The vanadium nitride material shows higher catalytic activity and stability when being applied to catalyzing the methanol oxidation reaction as a noble metal based catalyst carrier, and the vanadium nitride material has an excellent application prospect in the fields of low-temperature fuel cells.
Owner:INST OF PROCESS ENG CHINESE ACAD OF SCI

Preparation method of polyacrylic ester emulsion modified by hollow zinc oxide microspheres with shell layers adopting sheet structures

The invention relates to a preparation method of a polyacrylic ester emulsion modified by hollow zinc oxide microspheres with shell layers adopting sheet structures. The preparation method comprises the following steps: firstly, preparing the hollow zinc oxide microspheres with the shell layers adopting the sheet structures according to the alkaline etching mechanism and the Ostwald ripening mechanism; secondly, modifying a polyacrylic ester emulsion with the hollow zinc oxide microspheres by a physical blending method. The hollow zinc oxide microspheres with the shell layers adopting the sheet structures are formed through the prior etching of ammonia water or sodium hydroxide to the zinc hydroxide in zinc hydroxide/zinc oxide composite microspheres and the self-assembly process of oriented adsorption growth of zinc oxide nano particles, the preparation technology is simple, the reaction condition is moderate, and the operability and productivity are high, the prepared hollow zinc oxide microspheres with the shell layers adopting the sheet structures have uniform appearances. Compared with a pure polyacrylic ester coating, a polyacrylic ester emulsion coating modified by the method provided by the invention has the advantages that the moisture permeability is increased by 51%, the water tolerance is increased by 11.61%, and the tensile strength is increased by 60.26%.
Owner:SHAANXI UNIV OF SCI & TECH

Method for preparing amino acid-and-polypeptide-modified AIE polymer nanoparticles

A method for preparing amino acid-and-polypeptide-modified AIE polymer nanoparticles comprises the following steps: (1) dissolving an emulsifier and an amino functional monomer in water to obtain an aqueous solution; (2) dissolving an AIE molecule, an Ostwald ripening effect inhibitor and an oil-soluble initiator in a hydrophobic monomer to obtain an oil phase solution; (3) adding the aqueous solution to the oil phase solution, stirring and pre-emulsifying the obtained mixture to obtain a crude emulsion, carrying out ultrasonic treatment to obtain a fine monomer emulsion, introducing nitrogento remove oxygen, and carrying out a reaction to produce an amino-modified AIE polymer nanoparticle emulsion; (4) dissolving omega-maleimido alkyl acid and a carbodiimide condensing agent in an acidicpH buffer solution, and performing activation to obtain an activated intermediate solution; (5) adding the activated intermediate solution to the emulsion prepared in step (3), and carrying out a reaction to obtain a maleimide-modified AIE polymer nanoparticle emulsion; and (6) adding an aqueous solution of a polypeptide containing a cysteine sequence unit at the end to the emulsion prepared in step (5), and carrying out a reaction to produce the amino acid-and-polypeptide-modified AIE polymer nanoparticles.
Owner:ZHEJIANG SCI-TECH UNIV

High-efficiency catalyst for growing carbon nanotubes, and preparation method and use method thereof

The invention belongs to the technical field of preparation processes and application of nano materials, and relates to a high-efficiency catalyst for growing carbon nanotubes, and a preparation method and a use method thereof. The catalyst is composed of cobalt, iron, dysprosium metal, molybdenum oxide and aluminum oxide, and all the components are evenly distributed; due to introduction of dysprosium, aggregation, growth and deactivation caused by Ostwald ripening of the catalyst can be effectively inhibited, and the efficiency of the catalyst for growing the carbon nanotubes is greatly improved. Carbon-containing gas is used as a carbon source, the catalyst is flatly laid in a quartz boat, a chemical vapor deposition reaction is carried out in a horizontal tubular furnace to prepare thecarbon nanotubes, and the yield can reach 6000% or above (the ratio of a post-growth product to a pre-growth catalyst). The dysprosium metal doped catalyst with uniform components can be prepared andused for efficiently growing the carbon nanotubes, the preparation process is simple, convenient and feasible, the cost of the raw materials is low, the purity and graphitization degree of the growncarbon nanotubes are high, and the catalyst has great significance in promoting industrial production and application of high-quality carbon nanotubes.
Owner:JIANGXI COPPER TECHNOLOGY RESEARCH INSTITUTE CO LTD

W/O vaccine oil adjuvant formulation and preparation method thereof

The invention relates to a W / O vaccine oil adjuvant formulation and a preparation method thereof. The formulation is a W / O emulsion, which comprises an aqueous phase containing a solution of antigen and an oil phase containing white oil, an emulsifier, and a stabilizing agent. The W / O emulsion has the average particle size in a range of 0.1-8.22 [mu]m and the coefficient of dispersion less than 0.1. The preparation method comprises: transferring a pre-emulsion into a storage tank for quick membrane emulsification, and allowing the obtained product to pass through a microporous membrane under the pressure in a range of 0.1-2.5 MPa to obtain the W / O vaccine oil adjuvant formulation. The W / O vaccine oil adjuvant formulation is uniform and controllable in size. The improved uniformity of the emulsion benefits enhancement of stability of emulsion droplets. Compared with an emulsion prepared through a conventional process, the emulsion in the invention is slower in the Ostwald ripening, so that when the formulation is injected into a human body, the burst release of antigen is at a low speed, and antigen can be continuously released later, thereby inducing a quick, efficient and continuous immune response level.
Owner:INST OF PROCESS ENG CHINESE ACAD OF SCI

Preparation method of rare earth hollow nanocrystal

The invention discloses a preparation method of a rare earth hollow nanocrystal, wherein the preparation method comprises the following steps: preparing a rare earth soluble salt aqueous solution of rare earth ions La and Eu; preparing a lithium ion soluble salt aqueous solution; preparing a transparent solution from polyvinylpyrrolidone; dropwise adding the rare earth soluble salt aqueous solution and the lithium ion soluble salt aqueous solution into the obtained solution, to obtain a transparent solution; preparing an NH4F aqueous solution, slowly dropwise adding the NH4F aqueous solution to the obtained solution, to obtain a white colloidal solution; and pouring the obtained colloidal solution into a hydrothermal kettle, centrifuging, putting the obtained white product into a baking oven, and thus obtaining a rare earth hollow nanocrystalline powder. The LaF3:Eu<3+> hollow nanocrystal is formed by using self weight crystallization and localized Ostwald ripening; by doping Li<+> ions, the red luminescence intensity of the nanocrystal is greatly enhanced. The prepared rare earth hollow nanocrystal has the advantages of uniform size, good dispersion, high water solubility and fluorescence intensity and the like, and has highly important research and application significance in the aspects of biological fluorescence imaging, kinetics diagnosis and treatment, photocatalysis and the like.
Owner:FOSHAN UNIVERSITY
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