Monodisperse superparamagnetic nano crystal colloidal core-shell composite particles and preparation method thereof

A technology of composite particles and nanocrystals, which is applied in the direction of nanotechnology, nanotechnology, nanotechnology, etc. for materials and surface science, can solve problems such as the reduction of repulsive force distance, the influence of ionic strength and pH value, and improve the resistance Ability, high chemical and colloidal stability, wide color range effect

Active Publication Date: 2013-10-09
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is: for existing magnetic photonic crystals relying on electrostatic repulsion as long-range repulsion force, thus the distance of action of repulsion force decreases significantly as the polarity of the solvent decreases and is easily affected by ionic strength and pH value Shortcomings, providing a method for preparing superparamagnetic colloidal particles with stable steric hindrance to solve the above problems

Method used

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  • Monodisperse superparamagnetic nano crystal colloidal core-shell composite particles and preparation method thereof
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  • Monodisperse superparamagnetic nano crystal colloidal core-shell composite particles and preparation method thereof

Examples

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Effect test

Embodiment 1

[0048]Add glucose and polyvinylpyrrolidone to ethylene glycol to prepare a uniform mixed solution, the concentration of glucose is 10g / L, and the concentration of polyvinylpyrrolidone is 100g / L. Add ferric chloride hexahydrate into the mixed solution, stir until completely dissolved, the concentration of ferric ion in the solution is 4.6g / L, add an appropriate amount of anhydrous sodium acetate to adjust the pH of the system to 8.0. Then put it into a reaction kettle, seal it and heat it to 200°C, keep it warm for 12 hours, cool it down to room temperature, wash and separate it with ethanol for 2-3 times, and dry the solid in vacuum to get the product.

[0049] according to figure 1 From the field emission scanning electron microscope image of the product of this example, it can be known that the obtained product is 150 nm monodisperse colloidal particles. Depend on figure 1 The transmission electron microscope image of a single particle in the lower right corner shows that ...

Embodiment 2

[0051] Add glucose derivatives gluconic acid and polyvinylpyrrolidone to ethylene glycol to prepare a uniform mixed solution, the concentration of gluconic acid is 9g / L or 13.3g / L, and the concentration of polyvinylpyrrolidone is 100g / L. Then add ferric chloride hexahydrate into the mixed solution, stir until completely dissolved, and the concentration of ferric ion in the solution is 4.6g / L. Finally, sodium hydroxide was added to adjust the pH to 9.0. Then put it into a reaction kettle, seal it and heat it to 220°C, and keep it warm for 12 hours, then cool it down to room temperature, wash and separate it with ethanol for 2 to 3 times, and dry the solid in vacuum to obtain the product. 9g / L and 12g / L the scanning electron microscope morphology of glucose concentration gained product is as follows Figure 7 (9g / L) and Figure 8 (13.3g / L), the particle sizes are 100nm and 220nm respectively.

Embodiment 3

[0053] Add tannic acid and polyvinylpyrrolidone to ethylene glycol to prepare a uniform mixed solution, the concentration of tannic acid is 3.33g / L, and the concentration of polyvinylpyrrolidone is 400g / L. Then add ferric chloride hexahydrate into the mixed solution, stir until completely dissolved, and the concentration of ferric ion in the solution is 4.1g / L or 8.6g / L. Finally, anhydrous sodium acetate was added to adjust the pH to 9.0. Then put it into a reaction kettle, seal it and heat it to 200°C, and keep it warm for 24 hours, then cool it down to room temperature, wash and separate it with ethanol for 2 to 3 times, and dry the solid in vacuum to obtain the product. 4.1g / L and 8.6g / L the scanning electron microscope morphology of the product obtained by ferric ion concentration is as follows Figure 9 (4.1g / L) and Figure 10 (8.6g / L), the particle sizes are 90nm and 230nm respectively.

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Abstract

The invention discloses monodisperse superparamagnetic nano crystal colloidal core-shell composite particles, which are monodisperse superparamagnetic nano cluster particles which are gathered by ferroferric oxide nanocrystalline. The surfaces of the particles are coated by polyvinylpyrrolidone. The preparation method of the composite particles comprises the following steps: adding trivalent iron salt to polyol mixture solution of polyvinylpyrrolidone and polyhydroxy compounds; agitating until the trivalent iron salt is completely dissolved; adjusting the pH value to 8.0-10.0, then carrying out enclosed heating to 180-240 DEG C, and carrying out heat preservation for 6-48 hours. The monodisperse superparamagnetic nano crystal colloidal core-shell composite particles disclosed by the invention can be assembled into different colors of photonic crystal in a magnetic control manner; the dependency level of the magnetic photonic crystal on the solvent polarity, the ion strength and the pH value can be reduced.

Description

technical field [0001] The invention relates to the field of preparation of magnetic nanometer materials, in particular to a monodisperse superparamagnetic iron tetraoxide / polyvinylpyrrolidone nanocrystal cluster colloidal core-shell composite particle and a preparation method thereof. Background technique [0002] Magnetically responsive photonic crystals refer to a responsive photonic crystal material whose color can be controlled by changing the strength of an applied magnetic field. It has a wide range of uses in civilian fields such as sensing, display technology, mirrors, and energy saving. Significant progress has been made in the research of magnetically responsive photonic crystals based on iron ferric oxide submicron spheres. American "advanced materials" magazine (Adv.Mater.2001, volume 13, page 1681) reported a superparamagnetic PS colloidal microsphere containing 17% ferrite, but the magnetic component in the colloidal unit The content is too low, so the adjus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G49/08B82Y30/00H01F1/10
Inventor 官建国罗巍马会茹牟方志
Owner WUHAN UNIV OF TECH
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