Polyacetimide magnetic nano-particles with core-shell structure and preparation method thereof
阅读说明：本技术 具有核壳结构的聚乙酰亚胺磁性纳米颗粒及其制备方法 (Polyacetimide magnetic nano-particles with core-shell structure and preparation method thereof ) 是由 赵磊 张堃 鲁昱 高明远 于 2021-07-26 设计创作，主要内容包括：本发明公开了一种具有核壳结构的聚乙酰亚胺磁性纳米颗粒,所述的磁性纳米颗粒以Fe-(3)O-(4)为核,SiO-(2)为壳,壳表面修饰材料为聚乙酰亚胺。其制备方法包括：用热分解法合成油溶性的磁性纳米颗粒；将合成的油溶性磁性纳米颗粒经表面活性剂处理后得到分散于水中的磁性纳米颗粒；将得到的分散于水中的磁性纳米颗粒表面包覆一层SiO-(2)壳层,得到分散于水中的Fe-(3)O-(4)@SiO-(2)磁性纳米颗粒；向Fe-(3)O-(4)@SiO-(2)磁性纳米颗粒中加入溶有聚乙酰亚胺的醇溶液,反应得到Fe-(3)O-(4)@SiO-(2)@PEI磁性纳米颗粒。本发明可将热分解所得的油溶性磁性纳米颗粒进行表面修饰,表面修饰后的磁性纳米颗粒基团表面有大量的氨基基团,在水中分散性好。(The invention discloses a polyacetylimine magnetic nanoparticle with a core-shell structure, wherein the magnetic nanoparticle is made of Fe 3 O 4 As a core, SiO 2 The shell is made of a surface modification material of polyacetyl imine. The preparation method comprises the following steps: synthesizing oil-soluble magnetic nanoparticles by a thermal decomposition method; treating the synthesized oil-soluble magnetic nanoparticles with a surfactant to obtain magnetic nanoparticles dispersed in water; coating a layer of SiO on the surface of the obtained magnetic nano particles dispersed in water 2 Shell layer of Fe dispersed in water 3 O 4 @SiO 2 Magnetic nanoparticles; to Fe 3 O 4 @SiO 2 Adding an alcoholic solution dissolved with the polyacetylimine into the magnetic nano particles, and reacting to obtain Fe 3 O 4 @SiO 2 @ PEI magnetic nanoparticles. The invention can carry out surface treatment on the oil-soluble magnetic nano-particles obtained by thermal decompositionAnd (3) modifying, wherein a large number of amino groups are arranged on the surface of the surface modified magnetic nanoparticle group, and the dispersibility in water is good.)
1. The magnetic polyimide nano-particles with the core-shell structure are characterized in that the magnetic nano-particles are made of Fe3O4As a core, SiO2The shell is made of a surface modification material of polyacetyl imine.
2. The method for preparing the magnetic nano-particles of the polyacetyl imine with the core-shell structure according to claim 1, which comprises the following steps:
synthesizing oil-soluble magnetic nanoparticles by a thermal decomposition method;
treating the synthesized oil-soluble magnetic nanoparticles with a surfactant to obtain magnetic nanoparticles dispersed in water;
coating a layer of SiO on the surface of the obtained magnetic nano particles dispersed in water2Shell layer of Fe dispersed in water3O4@SiO2Magnetic nanoparticles;
to Fe3O4@SiO2Adding an alcoholic solution dissolved with the polyacetylimine into the magnetic nano particles, and reacting to obtain Fe3O4@SiO2@ PEI magnetic nanoparticles.
3. The method for preparing the magnetic nanoparticle of polyacetyl imine with core-shell structure according to claim 2, wherein the thermal decomposition method for synthesizing the oil-soluble magnetic nanoparticle is specifically as follows: dissolving an iron precursor in a high-boiling-point solvent, then adding a high-boiling-point reducing agent, removing the low-boiling-point solvent at 110-150 ℃ under a nitrogen atmosphere, and then heating to a set temperature for refluxing to obtain the oil-soluble magnetic nanoparticles.
4. The method for preparing the magnetic nano-particles of polyacetyl imine with the core-shell structure as claimed in claim 3, wherein the precursor of iron is one or more of iron pentacarbonyl, iron acetylacetonate and iron oleate, the high boiling point solvent is one or more of toluene, eicosane, n-octadecane and octadecene, the high boiling point reducing agent is one or two of oleic acid and oleylamine, the reflux temperature is 220-330 ℃, the reflux time is 0.5-2h, and the molar ratio of the precursor of iron, the high boiling point solvent and the high boiling point reducing agent is 1: (10-80): (1-9).
5. The method for preparing the magnetic nanoparticle of polyacetyl imine with core-shell structure according to claim 2, wherein the specific method for preparing the magnetic nanoparticle dispersed in water is as follows: dissolving the prepared oil-soluble magnetic nanoparticles in a polar solvent, adding a surfactant aqueous solution with the mass fraction of 0.5% -5%, controlling the temperature to be 60-90 ℃, stirring under the nitrogen atmosphere, and drying the polar solvent by blowing to obtain the magnetic nanoparticles dispersed in water.
6. The method for preparing the magnetic nano particles of polyacetyl imine with the core-shell structure according to claim 5, wherein the polar solvent comprises one or more of trifluoroacetic acid, dimethyl sulfoxide, N-dimethylformamide, pyridine, acetone, tetrahydrofuran and chloroform; the surfactant aqueous solution is one or more of an aqueous solution of sodium dodecyl benzene sulfonate, an aqueous solution of sodium dodecyl sulfate and an aqueous solution of tween; the mass ratio of the oil-soluble magnetic nanoparticle solution to the polar solvent to the surfactant aqueous solution is 1: (10-30): (200-400).
7. The method for preparing the magnetic nano particles of the polyacetyl imine with the core-shell structure according to claim 2, wherein the surface is coated with SiO2The specific preparation method of the magnetic nanoparticles of the shell layer comprises the following steps: adding ethanol into magnetic nanoparticles dispersed in water to control the volume of ethanol to be 8-12 times of that of water, adding ammonia water to adjust the pH of the system to be alkaline, adding tetraethoxysilane, reacting at 0-20 ℃, washing and dispersing in an alcohol solution to obtain Fe3O4@SiO2An alcohol dispersion of magnetic nanoparticles.
8. The method for preparing the magnetic nano particles of polyacetyl imine with core-shell structure according to claim 7, wherein the alcohol solution comprises one or more of methanol, ethanol, n-butanol and isopropanol, and the volume ratio of the magnetic nano particles dispersed in water to ethyl orthosilicate is 1: (0.03-0.1).
9. The method for preparing the magnetic nanoparticle of polyacetyl imine with core-shell structure according to claim 2, wherein the Fe dispersed in water3O4@SiO2The mass fraction of the magnetic nano particles is 0.4-4%, the mass fraction of the polyacetimide in the alcohol solution dissolved with the polyacetimide is 0.1-1%, then an aldehyde solvent with the mass fraction of 1-10% is dripped, the mixture is refluxed for 1-4h at the temperature of 60-90 ℃, and Fe is obtained after washing3O4@SiO2@ PEI magnetic nanoparticles.
10. The method for preparing the magnetic nanoparticle of the polyacetyl imine with the core-shell structure according to claim 9, wherein the alcohol solution comprises one or more of methanol, ethanol, n-butanol and isopropanol; the aldehydes are one or more of formaldehyde, acetaldehyde, succinaldehyde and glutaraldehyde; the Fe dispersed in water3O4@SiO2The volume ratio of the magnetic nanoparticles to the alcohol solution dissolved with the polyacetyl imine to the aldehyde solvent is 1: (0.1-0.3): (10-30)。
Technical Field
The invention relates to a polyacetylimine magnetic nanoparticle with a core-shell structure and a preparation method thereof, belonging to the technical field of composite materials.
Background
The magnetic nano-particles have the characteristics of excellent magnetic property, high specific surface area and low toxicity due to easy synthesis and surface modification. After surface modification, the surface modified nano-particles can be widely applied to the biomedical fields of nuclear magnetic resonance imaging, tumor diagnosis, biological separation, cell tracing, construction of multi-modal molecular imaging probes and the like. In recent years, many methods for synthesizing magnetic nanoparticles are gradually developed and perfected, but the directly synthesized magnetic nanoparticles have the disadvantages of poor dispersibility, poor biocompatibility, easy oxidation and the like, and the subsequent application of the magnetic nanoparticles is greatly limited, so that the magnetic nanoparticles are usually subjected to surface modification to improve the performance of the magnetic nanoparticles.
The commonly used preparation method of the magnetic nanoparticles is a chemical synthesis method, and mainly comprises a thermal decomposition method, a coprecipitation method, a solvothermal method and the like. The magnetic nanoparticles synthesized by the coprecipitation method or the solvothermal method have the defects of large particle size, poor monodispersity, poor crystallization effect and the like. The magnetic nano-particles synthesized by the method have large particle size and poorer monodispersity after surface modification. Magnetic nanoparticles synthesized by a thermal decomposition method have the advantages of small particle size, good monodispersity and high crystallinity, and most of the magnetic nanoparticles synthesized by the existing method are oil-soluble magnetic nanoparticles, so that the surface modification is difficult to perform, and the application of the magnetic nanoparticles is limited to a certain extent.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects of the prior art, and provide a method for synthesizing oil-soluble magnetic nanoparticles by a thermal decomposition method, coating a silicon dioxide shell layer by post-treatment, and then performing surface modification by using polyacetyl imine, wherein a large number of amino groups are arranged on the surface of the surface-modified magnetic nanoparticle group, and the dispersibility in water is good.
In order to solve the technical problems, the invention provides a polyacetylimine magnetic nanoparticle with a core-shell structure, and the magnetic nanoparticle is made of Fe3O4As a core, SiO2Is a shell, a shell surfaceThe modifying material is polyacetyl imine.
The invention provides a preparation method of a polyacetyl imine magnetic nano particle with a core-shell structure, which comprises the following steps:
synthesizing oil-soluble magnetic nanoparticles by a thermal decomposition method;
treating the synthesized oil-soluble magnetic nanoparticles with a surfactant to obtain magnetic nanoparticles dispersed in water;
coating a layer of SiO on the surface of the obtained magnetic nano particles dispersed in water2Shell layer of Fe dispersed in water3O4@SiO2Magnetic nanoparticles;
to Fe3O4@SiO2Adding an alcoholic solution dissolved with the polyacetylimine into the magnetic nano particles, and reacting to obtain Fe3O4@SiO2@ PEI magnetic nanoparticles.
Further, the thermal decomposition method for synthesizing the oil-soluble magnetic nanoparticles specifically comprises the following steps: dissolving an iron precursor in a high-boiling-point solvent, then adding a high-boiling-point reducing agent, removing the low-boiling-point solvent at 110-150 ℃ under a nitrogen atmosphere, and then heating to a set temperature for refluxing to obtain the oil-soluble magnetic nanoparticles.
Further, the precursor of iron is one or more of iron pentacarbonyl, iron acetylacetonate and iron oleate, the high-boiling point solvent is one or more of toluene, eicosane, n-octadecane and octadecene, the high-boiling point reducing agent is one or two of oleic acid and oleylamine, the reflux temperature is 220-330 ℃, the reflux time is 0.5-2h, and the molar ratio of the precursor of iron to the high-boiling point solvent to the high-boiling point reducing agent is 1: (10-80): (1-9).
Further, the specific preparation method of the magnetic nanoparticles dispersed in water comprises the following steps: dissolving the prepared oil-soluble magnetic nanoparticles in a polar solvent, adding a surfactant aqueous solution with the mass fraction of 0.5% -5%, controlling the temperature to be 60-90 ℃, stirring under the nitrogen atmosphere, and drying the polar solvent by blowing to obtain the magnetic nanoparticles dispersed in water.
Further, the polar solvent comprises one or more of trifluoroacetic acid, dimethyl sulfoxide, N-dimethylformamide, pyridine, acetone, tetrahydrofuran and chloroform; the surfactant aqueous solution is one or more of an aqueous solution of sodium dodecyl benzene sulfonate, an aqueous solution of sodium dodecyl sulfate and an aqueous solution of tween; the mass ratio of the oil-soluble magnetic nanoparticle solution to the polar solvent to the surfactant aqueous solution is 1: (10-30): (200-400).
Further, the surface is coated with SiO2The specific preparation method of the magnetic nanoparticles of the shell layer comprises the following steps: adding ethanol into magnetic nanoparticles dispersed in water to control the volume of ethanol to be 8-12 times of that of water, adding ammonia water to adjust the pH of the system to be alkaline, adding tetraethoxysilane, reacting at 0-20 ℃, washing and dispersing in an alcohol solution to obtain Fe3O4@SiO2An alcohol dispersion of magnetic nanoparticles.
Further, the alcohol solution comprises one or more of methanol, ethanol, n-butanol and isopropanol, and the volume ratio of the magnetic nanoparticles dispersed in water to ethyl orthosilicate is 1: (0.03-0.1).
Further, the Fe dispersed in water3O4@SiO2The mass fraction of the magnetic nano particles is 0.4-4%, the mass fraction of the polyacetimide in the alcohol solution dissolved with the polyacetimide is 0.1-1%, then an aldehyde solvent with the mass fraction of 1-10% is dripped, the mixture is refluxed for 1-4h at the temperature of 60-90 ℃, and Fe is obtained after washing3O4@SiO2@ PEI magnetic nanoparticles.
Further, the alcohol solution comprises one or more of methanol, ethanol, n-butanol and isopropanol; the aldehydes are one or more of formaldehyde, acetaldehyde, succinaldehyde and glutaraldehyde; the Fe dispersed in water3O4@SiO2The volume ratio of the magnetic nanoparticles to the alcohol solution dissolved with the polyacetyl imine to the aldehyde solvent is 1: (0.1-0.3): (10-30).
The invention achieves the following beneficial effects:
(1) the invention is in magnetic nanometerThe surface of the particle is coated with a layer of SiO2Shell layer of SiO2As an excellent magnetic nano-particle inorganic surface modifier, the magnetic nano-particle inorganic surface modifier has the advantages of improving the biocompatibility, the dispersibility, the hydrophilicity and the like of the magnetic nano-particles. And because the self has stronger negative charge, the subsequent group is easy to further modify.
(2) The magnetic nano-particles prepared by the thermal decomposition method have the characteristics of good monodispersity and controllable particle size, but are mostly oil-soluble. The invention can carry out surface modification on oil-soluble magnetic nano particles obtained by thermal decomposition, and the specific method comprises the steps of treating the oil-soluble magnetic nano particles by a surfactant to change the oil-soluble magnetic nano particles from hydrophobicity to hydrophilicity, then coating a silicon dioxide shell layer on the surfaces of the oil-soluble magnetic nano particles, modifying the polyacetyl imine by adopting an electrostatic adsorption mode because the silicon dioxide surfaces have stronger negative charges, and leading the surfaces of the magnetic nano particle groups after surface modification to have a large number of amino groups and to have good dispersibility in water. The preparation method is simple, effective and good in repeatability.
Drawings
FIG. 1 shows oil-soluble Fe synthesized in example 13O4Transmission electron microscopy of magnetic nanoparticles;
FIG. 2 shows oil-soluble Fe synthesized in example 13O4A particle size distribution map of the magnetic nanoparticles;
FIG. 3 shows Fe synthesized in example 13O4@SiO2Transmission electron microscopy of magnetic nanoparticles;
FIG. 4 shows Fe synthesized in example 13O4@SiO2A particle size distribution map of the magnetic nanoparticles;
FIG. 5 shows Fe synthesized in example 13O4@SiO2A transmission electron micrograph of the @ PEI magnetic nanoparticles;
FIG. 6 shows Fe synthesized in example 13O4@SiO2The particle size distribution of the @ PEI magnetic nanoparticles.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Example 1:
1. preparation of oil soluble Fe by high temperature thermal decomposition method3O4Magnetic nanoparticles
Adding 26.4g of octadecene and 2.1g of oleic acid into 9.0g of iron oleate solid, stirring for half an hour under the nitrogen atmosphere, rapidly heating to 330 ℃, refluxing for 0.5h, collecting a product, and washing with ethanol for several times to obtain oil-soluble Fe3O4Magnetic nanoparticles. FIG. 1 shows oil-soluble Fe synthesized in this example3O4Transmission electron microscopy of magnetic nanoparticles. FIG. 2 shows the oil-soluble Fe synthesized in this example3O4The particle size distribution diagram of the magnetic nanoparticles is 4.98nm, and the coefficient of variation is 20.35%.
2. Increase of Fe3O4Dispersibility of magnetic nanoparticles
500mg of the oil-soluble Fe3O4Magnetic nanoparticles 5mL of tetrahydrofuran was added, and after stirring to dissolve, 150mL of an aqueous solution of sodium dodecyl sulfate (2.5% w/v) was added. Mechanically stirring after uniform ultrasonic dispersion, introducing nitrogen, heating to 60 ℃, collecting the residual liquid after opening the mouth for 5 hours, centrifuging for several times by using ethanol and deionized water, and dispersing in 5mL of deionized water to obtain uniformly dispersed Fe3O4An aqueous dispersion of magnetic nanoparticles.
3、Fe3O4Coating of magnetic nano particle surface silicon dioxide shell layer
Taking the Fe dispersed in deionized water3O4Adding 250mL of ethanol and 5mL of deionized water into magnetic nanoparticles, mechanically stirring in an ice-water bath, adding ammonia water to adjust the pH value of a system to be between 8 and 9, stirring for half an hour, adding 0.5mL of tetraethoxysilane, stirring for 2 hours, adding 0.5mL of tetraethoxysilane, stirring at normal temperature for 12 hours, collecting the obtained product, centrifuging for several times by using ethanol and deionized water, and dispersing in 5mL of methanol to obtain Fe3O4@SiO2A methanol dispersion of magnetic nanoparticles. FIG. 3 shows Fe synthesized in this example3O4@SiO2Transmission of magnetic nanoparticlesMirror image. FIG. 4 shows Fe synthesized in this example3O4@SiO2The particle size distribution diagram of the magnetic nanoparticles is 9.74nm, and the coefficient of variation is 9.39%.
4、 Fe3O4@SiO2Modification of magnetic nanoparticle surface polyacetyl imine
5mL of the above Fe3O4@SiO2Adding 25mL of a methanol solution (3% w/v) of polyimide into the methanol dispersion liquid of the magnetic nanoparticles, heating to 70 ℃, then dropwise adding 50mL of a methanol solution (3% w/v) of formaldehyde, refluxing for 4 hours, repeatedly centrifuging and washing the mixture by using methanol until the upper layer liquid is colorless and transparent, and drying the liquid in vacuum and then dispersing the liquid in water. FIG. 5 shows Fe synthesized in this example3O4@SiO2Transmission electron microscopy of @ PEI magnetic nanoparticles. FIG. 6 shows Fe synthesized in this example3O4@SiO2The particle size distribution diagram of the @ PEI magnetic nanoparticles is 11.98nm, and the coefficient of variation is 5.81%.
Example 2:
1. preparation of oil soluble Fe by high temperature thermal decomposition method3O4Magnetic nanoparticles
Taking 4.5g of iron acetylacetonate solid, adding 25.3g of toluene, 4.0g of oleic acid and 4.5g of oleylamine, stirring for half an hour under the nitrogen atmosphere, rapidly heating to 270 ℃, refluxing for 2 hours, collecting a product, washing the product with ethanol until the upper layer is colorless and transparent, and obtaining oil-soluble Fe3O4Magnetic nanoparticles.
2. Increase of Fe3O4Dispersibility of magnetic nanoparticles
500mg of the oil-soluble Fe obtained above was taken3O4The magnetic nanoparticles were dissolved in 5mL of chloroform and 50mL of an aqueous solution of Tween-80 (1% w/v) was added. Heating to 90 ℃ while stirring, collecting liquid after 1h of opening, centrifuging for a plurality of times by using ethanol and deionized water, and dispersing in 5mL of deionized water to obtain Fe3O4An aqueous dispersion of magnetic nanoparticles.
3、Fe3O4Coating of magnetic nano particle surface silicon dioxide shell layer
To the dispersion obtained aboveAnd (3) adding ethanol and deionized water into the solution in sequence, wherein the ratio of the ethanol to the water is 9: 1, after uniformly stirring, adding 1.5mL of ammonia water, stirring for half an hour at 20 ℃, adding 1mL of tetraethoxysilane for five times at intervals of 10min, collecting the obtained product after stirring for 12h, centrifugally washing the product by using ethanol and deionized water at a low rotating speed (1000 rpm) until no white particles exist, and dispersing the product in 5mL of ethanol to obtain Fe3O4@SiO2An ethanol dispersion of magnetic nanoparticles.
4、Fe3O4@SiO2Modification of magnetic nanoparticle surface polyacetyl imine
5mL of the above Fe3O4@SiO2Adding 5mL of an ethanol solution (3% w/v) of polyimide into the ethanol dispersion liquid of the magnetic nanoparticles, stirring until the mixture is uniformly mixed, heating to 80 ℃, dropwise adding 50mL of an aqueous solution (3% w/v) of glutaraldehyde, continuously refluxing for 1h after all the liquid is dropwise added, centrifugally washing the mixture by using ethanol and water until the upper layer liquid is colorless and transparent, and volatilizing the liquid and dispersing the liquid in water.
Example 3:
1. preparation of oil soluble Fe by high temperature thermal decomposition method3O4Magnetic nanoparticles
Adding 37.9g of diethylene glycol and 1.4g of oleylamine into 2.3g of iron pentacarbonyl solid, stirring for half an hour under the nitrogen atmosphere, rapidly heating to 240 ℃, refluxing for 1h, collecting a product, washing the product with n-hexane and ethanol for several times to obtain oil-soluble Fe3O4Magnetic nanoparticles.
2. Increase of Fe3O4Dispersibility of magnetic nanoparticles
500mg of the oil-soluble Fe obtained above was taken3O4The magnetic nanoparticles were dissolved in 5mL of tetrahydrofuran, and 100mL of an aqueous solution of sodium dodecylbenzenesulfonate (2.5% w/v) and 50mL of an aqueous solution of Tween-80 (1% w/v) were added. Heating to 80 ℃ while stirring, collecting liquid after 1h of opening, centrifuging for a plurality of times by using ethanol and deionized water, and dispersing in 5mL of deionized water to obtain Fe3O4An aqueous dispersion of magnetic nanoparticles.
3、Fe3O4Coating of magnetic nano particle surface silicon dioxide shell layer
Taking 250mL of ethanol and 5mL of deionized water, stirring and adding the obtained dispersion, adding 7.5mL of ammonia water, adding 1.5mL of ethyl orthosilicate, stirring for 12 hours, collecting the obtained product, centrifugally washing the product by using ethanol and deionized water until the upper layer is colorless and transparent, and dispersing the product in 5mL of isopropanol to obtain Fe3O4@SiO2An isopropanol dispersion of magnetic nanoparticles.
4、Fe3O4@SiO2Modification of magnetic nanoparticle surface polyacetyl imine
5mL of the above Fe3O4@SiO2Adding 25mL of an isopropanol solution (3% w/v) of polyimide into the isopropanol dispersion liquid of the magnetic nanoparticles, heating to 70 ℃, then dropwise adding 50mL of an aqueous solution (3% w/v) of glutaraldehyde, then continuously refluxing for 1h, centrifugally washing the mixture by using ethanol until the upper layer liquid is colorless and transparent, and volatilizing the liquid and then dispersing in water.
Comparative example:
500mg of the oil-soluble Fe synthesized in example 1 were taken3O4And adding 5mL of tetrahydrofuran into the magnetic nanoparticles, performing ultrasonic dispersion uniformly, then mechanically stirring, and introducing nitrogen. Adding 250mL of ethanol and 5mL of deionized water, mechanically stirring in an ice-water bath, adding ammonia water to adjust the pH value of the system to be between 8 and 9, stirring for half an hour, adding 0.5mL of tetraethoxysilane, stirring for 2 hours, adding 0.5mL of tetraethoxysilane, stirring for 12 hours at normal temperature, and collecting the obtained product, wherein a black bulk solid floats on the liquid surface of the reaction system, and a milky solid exists at the bottom. The black solid floating on the liquid surface is oil-soluble Fe3O4The magnetic nano-particles and the milky white solid at the bottom are hydrolysis products of the tetraethoxysilane. Oil soluble Fe3O4The surface of the magnetic nano-particles is not coated with SiO2And (4) shell layer.
In contrast, in example 1, the oil-soluble magnetic nanoparticles were treated with a surfactant to change them from hydrophobic to hydrophilic, thereby facilitating the coating of SiO on the surfaces thereof2And (4) shell layer. SiO 22As an excellent magnetic nano-particle inorganic surface modifier, the magnetic nano-particle inorganic surface modifier has the advantages of improving the biocompatibility, the dispersibility, the hydrophilicity and the like of the magnetic nano-particles. And isBecause the self has stronger negative charge, the subsequent group can be easily further modified. SiO 22The surface of the magnetic nano particle has stronger negative charges, the polyimide can be modified in an electrostatic adsorption mode, and the surface of the magnetic nano particle after surface modification has a large number of amino groups, so that the magnetic nano particle has good dispersibility in water.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.