130results about How to "Monodisperse" patented technology

The invention belongs to the technical field of nano material preparation, and discloses a hollow nanosphere material as well as a preparation method and an application thereof. The hollow nanosphere material is obtained by stacking nanospheres, the BET specific surface area of the hollow nanosphere material is 44-1226m<2>g<-1>, the total pore volume of the hollow nanosphere material is 0.15-1.20cm<3>g<-1>; the nanosphere is of a micropore shell-hollow nano structure, the diameter of the hollow cavity is 80-260nm, the thickness of the shell layer is 5-85nm, single-dispersion coefficient is as low as 0.005, and shell layer material is a polymer or carbon. By utilizing a hyper-crosslinking method, the stable inheritance of the hollow cavity of the polymer nanosphere and grid micropores of the shell layer in the normal-pressure drying and high-temperature carbonization processes is achieved; the single-dispersion coefficient of the hollow nanosphere material is as low as 0.005, the specific surface area is as high as 1226m<2>g<-1>, and the total pore volume is as high as 1.20cm<3>g<-1>.

The invention discloses a method for preparing a mesoporous silicon dioxide microsphere with controllable aperture. The method takes a novel tetra-quaternary ammonium salt cation surface active agent as a structure-directing agent and synthesizes the mesoporous silicon dioxide microsphere in an ethanol water system under the alkaline condition by a sol-gel method. The method has the advantages that the prepared silicon dioxide is micron spherical particles and has good monodispersion and large specific surface area; the mesoporous microsphere with large aperture can be prepared without an expanding agent; and the silicon dioxide microsphere prepared by the method has stable performance and is suitable for high-efficiency liquid-phase chromatographic separation and analysis.

The invention discloses a new compound Fe3O4/Au magnetic compound Nami grain method, which is characterized in that: the invention utilizes supersonic chemical method to restore gold ion on a amino or hydrosulfuryl functional magnetic Nami grain to realize the preparation of the sample. The method doesn't need purifying product, which is quick and directviewing and is a novel compound method with simple and quick operation and high yield.

The invention relates to a preparation method for a core-shell structure nanocrystal, wherein a nanocrystal in the shape of a spot particle containing selenium compound is dissolved in a solvent added with an additive, then the oxygen contained in the solution is eliminated in an environment of inertia gas to obtain a solution 1, then sulfur and the precursor of 12th group of elements are respectively dissolved in solutions with the same solvent and mixed so as to obtain a solution 2, which is dripped into the solution 1, then the mixed solution is heated up to 120-280 DEG C to make the nanocrystal to grow, so as to obtain the core-shell structure nanocrystal with the nanocrystal containing the selenium compound as the core and with the sulfide as the shell; the additive is an organic amine or an organic acid, each of which contains the carbons not less than 10; and the solvent is a non-coordinate solvent with the boiling point no higher than 60 DEG C; and the molecular ratio between the sulfur and the 12th group of elements is 1:1-1.5. The invention is characterized in simplified procedures, easy operation, environment-friendly solvent, low cost which can be saved by more than 50percent, and great application value on both laboratorial and industrial synthesis.

The invention discloses a method for preparing melamine-formaldehyde resin fluorescent microspheres. The method comprises the following steps of: preparing soluble melamine-formaldehyde prepolymer by using melamine and formaldehyde as raw materials; adding fluorochrome into the prepared prepolymer solution, and adsorbing fluorochrome molecules to wrap the branched prepolymer molecules; and heating to perform further intramolecular and intermolecular polycondensation on the prepolymer to obtain monodisperse fluorescent microspheres of which the particle size can be controlled and which can wrap various fluorochromes. The fluorescent microspheres prepared by the method have the characteristics of stable fluorescence property, organic solvent resistance, high temperature resistance and the like, and have wide application prospect in the fields of tissue marking, immunological detection, correction of fluorescence optical equipment and the like.

The invention relates to carboxyl functionalized polyurethane coated magnetic microspheres and a preparation method thereof. The preparation method comprises the following steps: firstly, preparing cross-linked polystyrene microspheres; secondly, performing surface functionization on the cross-linked polystyrene microspheres, and modifying one of amino, carboxyl, sulfonyl, methoxyl or chloromethyl; magnetizing the microspheres, and coating the magnetized cross-linked polystyrene microspheres by a polyurethane coating; finally performing carboxyl functionalization on the microspheres. The carboxyl functionalized polyurethane coated magnetic microspheres prepared by using the method have the characteristics of single dispersion, high suspension, high biocompatibility and relatively intense magnetic response, and have good practical values and application prospects in enzyme immobilization, immunoassay, cell separation, environment heavy metal detection analysis, and the like.

The invention provides a method for preparing a three-dimensional ordered macroporous material by using a water-soluble colloidal crystal as a template. The method comprises the steps of preparing the colloidal crystal template by using the prepared water-soluble monodisperse polyacrylamide nanoparticles and removing the template by using water as the solvent to obtain the three-dimensional ordered macroporous material. The invention develops a new method for preparing three-dimensional ordered macroporous polymer. Comparing with the traditional hydrofluoric acid etching and calcining, the method provided by the invention can maintain the gloss and chemical structure of the polymer, and is also energy-saving and environment-friendly.

The invention discloses a preparation method of a high-performance gold-shell magnetic microsphere and surface enhanced Raman scattering (SERS) application of the high-performance gold-shell magnetic microsphere. A substrate uses a Fe3O4 microsphere of 100-1,000 nanometers as a core to provide magnetism, polymer polyethyleneimine (PEI) is used as a multi-functional sandwiched layer to improve the dispersibility of the magnetic microsphere and absorb gold seeds of 3-5 nanometers, and finally, a uniform and stable gold shell is prepared by a seed reduction method. The preparation method comprises the following steps of firstly, modifying Fe3O4 microsphere with the PEI to form a polymer protection layer, and absorbing the gold seeds of 3-5 nanometers by means of strong positive electricity of polyethyleneimine; secondly, rapidly reducing the uniform and stable gold shell under an ultrasonic condition by a seed growing method and by taking hydroxylamine hydrochloride as a reducing agent; thirdly, adding high-concentration povidone (PVP) to improve the dispersibility of particles; and finally, obtaining the high-performance gold-shell magnetic microsphere. The invention also discloses application of the gold-shell magnetic microsphere prepared by the method in SERS detection. The gold-shell magnetic microsphere is high in magnetic response, good in dispersibility and stable in structure, has excellent SERS performance and can be used for SERS detection and analysis on various pollutants, pesticide residue, pathogenic microorganism and the like in a solution.

The invention discloses a three-dimensional micro-nano material composed of nano CoFe2O4 and a preparation method thereof. The three-dimensional micro-nano material is of a double-hexagon flower dumbbell type opposite-connected structure and is obtained by the following steps: 1) adding tervalent iron salt and divalent cobalt salt in polyol, stirring to obtain transparent liquid, heating for reacting, and then cooling to room temperature and collecting precipitates; 2) centrifugally washing the precipitates with ethanol, and drying so as to obtain a yellow green cobalt ferrite precursor; and 3) firing the precursor so as to obtain the CoFe2O4 micro-nano structure with the double-hexagon flower dumbbell type opposite-connected structure. According to the invention, the process is simple and practicable, the distribution range of the obtain material particle is narrow, and the micro-nano material has the advantages of single dispersibility, single product phase and good reaction repeatability; and the synthesized material simultaneously has characteristics and advantages of a micro-nano structure and a nano structure.

The invention relates to the technical field of preparation of carbon nanomaterials and provides a preparation method of nitrogen-doped fluorescent carbon dots. The preparation method comprises the following steps: 1, a carbon source is broken, ground, sieved by a 200-mesh sieve and dried in an oven; 2, the carbon source dried by the oven is weighed and placed into a 50-ml beaker, then an organic solvent is added, and a mixture is stirred sufficiently and subjected to ultrasonic processing for 0.8-1.2 h; 3, the mixture prepared in the step 2 is placed in a 50-ml hydrothermal kettle to have a hydrothermal reaction for 2-12 h, and the temperature is controlled at 60-180 DEG C; 4, after step 3, a suspension is taken out and placed into a high-speed desk centrifuge, supernatant liquor is taken out after 10-20 min of centrifugation, and hydrosol of the fluorescent carbon dots is obtained; 5, the hydrosol, obtained in the step 4, of the fluorescent carbon dots is placed in rotary evaporation equipment, the organic solvent is removed, and the target product fluorescent carbon dots are prepared. The preparation method of the nitrogen-doped fluorescent carbon dots has the characteristics of green and environment-friendly reaction conditions, easiness in control and easiness in mass production and preparation and is expected to be widely applied to the fields of photoelectric devices, bio-imaging, detection, sensing and the like.

The invention relates to a graphene/ chitosan compound micro-capsule and preparation method thereof. The compound micro-capsule is regular in shape and uniform in granularity distribution; the mechanical performance of film wall is obviously improved; the compound micro-capsule is formed by in-situ introducing graphene into the film wall of a chitosan micro-capsule, wherein the compound micro-capsule is spherical and 300 to 1000 microns in size, and the granularity distribution coefficient is not greater than 6%. The preparation method of the compound micro-capsule comprises the steps of modifying graphene through chitosan quaternary ammonium salt to ensure that graphene can be stably dispersed in a chitosan solution; generating mixed micro drops of graphene/ chitosan in an independent micro-flow control device based on the air-liquid shearing effect; dropping into an anionic surfactant solution; performing compound flocculation to synchronously separate out chitosan quaternary ammonium salt modified graphene and chitosan to form micro-capsule film wall so as to obtain the graphene/ chitosan compound micro-capsule; graphene is in-situ introduced into the film wall of the micro-capsule. The method is simple to operate, mild in condition, and high in reproducibility.

The invention belongs to the technical field of high molecular materials and analysis and relates to a monodisperse core-shell structure polymer nano particle as well as preparation and application thereof. The polymer nano particle is a core-shell type copolymer of an acrylic acid cross-linking agent and a monoene phenylboronic acid functional monomer; and the polymer nano particle is prepared by using a one-pot method, that is, precipitation polymerization with the combination of in-situ package strategy. Synthesis steps of the conventional core-shell structure polymer particles are simplified, and the polymer nano particle has the characteristics of rapidness, convenience and easiness, low cost, multiple boric acid functional monomers on the surface, and the like. The polymer nano particle can be used for separating or enriching glycoprotein with a 1,2-cis-glycol structure, and has good practical values and application prospects in the fields of proteomics and the like.

The invention relates to phase-change microcapsules with a solid-solid phase transition core material, and a preparation method thereof. The preparation method provided by the invention adopts a first coating and then in-situ polymerization method. A comb-type polymer with large amount of long-chain alkyl side-chain grafted on a main chain, such as polyacrylate, is adopted as a phase-change microcapsule core material; and a heat-resistant high-molecular material is adopted as a capsule wall for coating the core material, such that the phase-change microcapsule material is prepared. The phase-change microcapsule material is composed of a phase-change core material with polyacrylate with solid-solid phase transition property and with C12-C20 alkyl chain contained in the side-chain, and a melamine resin wall material with good heat resistance. The content of polyacrylate in the phase-change microcapsules is 5-80wt%. The phase-change microcapsules provided by the invention have good dimension controllability, and are in a monodisperse state. The heat resistance of the microcapsules is better than that of traditional phase-change microcapsules with small-molecular long-chain alkane as the core material. Therefore, application requirements by fields with higher requirements on heat resistance can be satisfied.

The invention discloses mono-disperse gallium oxide powder and a method for preparing high-density ceramic targets from the mono-disperse gallium oxide powder. The method includes dissolving metal gallium materials with the purity higher than 99.99% in acid and preparing clear gallium salt solution; adding precipitants into the clear gallium salt solution to generate precipitates; washing, filtering, drying and calcining the obtained precipitates to obtain the mono-disperse ultrafine gallium oxide powder; carrying out compression molding and cold isostatic pressing strengthening on the synthesized mono-disperse gallium oxide powder to obtain gallium oxide green bodies; sintering the green bodies in high-temperature furnaces to obtain the high-density gallium oxide ceramic targets with uniform microscopic structures. The mono-disperse gallium oxide powder and the method have the advantages of simple process, convenience in operation, high yield, applicability to industrial production and the like.

The invention discloses an oil-soluble monodisperse nano cerium dioxide catalyst as well as a preparation method and application thereof. The cerium dioxide catalyst comprises nano cerium dioxide particles and a low-polarity liquid-phase medium, wherein the surfaces of the nano cerium dioxide particles are coated with a surfactant layer, and the nano cerium dioxide particles coated with the surfactant layer are uniformly dispersed in a low-polarity liquid-phase medium to form a transparent dispersion. The solid content of the transparent dispersion of the nano cerium dioxide catalyst providedby the invention is 5wt.%-60wt.%; the cerium dioxide crystal is small in particle size, and the one-dimensional size of the cerium dioxide crystal is 1-10 nm; monodispersity is achieved, particle sizedistribution is uniform, and dispersity is good; the product has high transmittance, high purity and high stability, and is still transparent and free of sedimentation after standing for more than orequal to 6 months.

The invention relates to a method for preparing Au and Agx (Au) 1-x nano-crystals through organic phases. Stable organic gold salts of AuPPh3Cl serve as a precursor of gold to prepare Au and Agx (Au) 1-x nano-crystals. Avoiding current international seed growing methods by which water phases are used for synthesizing Au and Agx (Au) 1-x nano-crystals of large sizes, the method is simple in experiment processes and uses oleyamine as a reductant, a stabilizer and a dissolvent of Au. Prepared Au nano-crystal sizes are in a range of 5 nm to 100 nm, nanorod sizes range from 60 nm to 100 nm, nano cube sizes range from 6 nm to 15 nm, and absorption peaks are in a range of 530 nm to 560 nm. Prepared Agx (Au) 1-x nano-crystal sizes are in a range of 6 nm to 15 nm, and absorption peaks are in a range of 450 nm to 510 nm. Au and Agx (Au) 1-x nano-crystals prepared by the method can be transferred to water phases and can exist stably. According to the method, the method is simple and efficient, the reaction condition is mild, reagents are easy to obtain, the method is repeatable, and the synthesizing of Au nano-crystals with widely distributed sizes is controllable.

The invention provides a preparation method of high-purity superfine cobalt oxalate powder, which comprises the following steps: adding a certain amount of additive into a cobalt salt solution with a certain concentration, adding a certain amount of ammonia water into an ammonium oxalate solution with a certain concentration, and adding the two solutions into a reaction kettle to react according to a certain mole ratio in a parallel-flow uniform speed spray mode while controlling the reaction temperature at 15-55 DEG C, the pH value of the reaction solution at 6-7 and the stirring rate at 10-100 rpm/minute; and after finishing feeding, aging, washing, carrying out solid-liquid separation, and drying to finally obtain the high-purity superfine cobalt oxalate powder body. The cobalt oxalate powder prepared by the preparation method has the advantages of fewer impurities, high purity and high flowability, the average particle size is 0.5-1.5 micrometers, the particle size distribution is uniform, and the shape is subsphaeroidal. The preparation method has the advantages of simple and controllable technique, high production efficiency and stable product quality, and is suitable for large-scale industrial production.

The invention relates to a preparation method for high-crystallinity silver powder. The preparation method is characterized by comprising the following steps of: firstly, synthesizing a silver carbonate precursor; uniformly coating the silver carbonate precursor by using a coating agent; and performing low-temperature crystal water removing, high-temperature thermal decomposition, densification sintering and washing on the coated silver carbonate precursor to obtain high-crystallinity silver powder. Due to the adoption of the method disclosed by the invention, high-crystallinity silver powder of which the particle diameter is 0.1-5 mu m and the tap density is 3.0-7.0 g/cm<3> can be finally obtained; the silver powder can be used for preparing silver slurry or silver paste for fine threads and high-accuracy printed galvanic circles; the silver powder has the advantages of high dispersity, high crystallinity, superior degree of sphericity, uniform particle size distribution, easiness for dispersing in silver slurry or silver paste and high filling characteristic, so that high-accuracy fine thread printing can be realized; and meanwhile, an obtained silver thick film has low sintering concentration rate and low bulk resistivity.

The invention provides a preparation method of micron-sized spherical silver powder. The preparation method comprises the following steps: S1, preparing a silver nitrate solution, adding trisodium citrate into the silver nitrate solution, and uniformly mixing to obtain a precursor solution; S2, preparing an ascorbic acid solution, and adding Arabic gum, polyvinylpyrrolidone and polyethylene glycol into the ascorbic acid solution to obtain a reducing agent solution; and S3, at the temperature of 20-60 DEG C and under the dark condition, rapidly pouring the precursor solution into the reducing agent solution, conducting continuous stirring till the reaction is completed, and obtaining the micron-sized spherical silver powder. The silver powder is high in sphericity degree and free of irregular shapes such as flakes and dendrites.