CN1747078A - Modified water-base magnetic liquid of polymer and production thereof - Google Patents
Modified water-base magnetic liquid of polymer and production thereof Download PDFInfo
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Abstract
The water-base magnetic liquid modified with polymer is composed of nano magnetic particles, surface modifier and carrier liquid. The nano magnetic particles are of Fe3O4. The surface modifier is straight chain polyethylene imine (L-PIEI).The carrier liquid is water. The process for preparing the water-base magnetic liquid includes following steps: 1, synthesis of nano magnetic particle; 2, washing nano magnetic particle; 3, preparation of nano magnetic particle sol; 4, modification of nano magnetic particle; 5, purification of water-base magnetic liquid. The water-base magnetic liquid can be attached to DNA plasmids with 2.5-3.3 emu/g magnetizations. It has 10 nm average diameter, 50 nm average radius of hydrodynamic power, 3-11 pH value and 2.5-3.3 emu/g magnetizations.
Description
Technical Field
The invention relates to the field of nanotechnology, in particular to a polymer modified water-based magnetic liquid and a preparation method thereof.
Background
The magnetic liquid is a stable colloidal system in which the nano-magnetic particles having the surface modifier adsorbed thereon are highly dispersed in a carrier liquid. Mainly comprises three parts of nano magnetic particles, a surface modifier and a carrier liquid. The process technology can be described by the following points:
firstly, selecting and preparing nano magnetic particles: the commonly used magnetic materials include ferroferric oxide, iron, cobalt, ferrite, iron nitride and the like, and the magnetic material is nano Fe3O4The magnetic particles have the advantages of simple preparation, no toxicity, biocompatibility, biodegradability and the like, so the magnetic particles are widely adopted in medical water-based magnetic liquid. The preparation method of the nano magnetic particles mainly comprises a mechanical grinding method, a thermal decomposition method, a spark erosion method, a reduction method, a chemical coprecipitation method and the like, wherein the chemical coprecipitation method is an economical and effective method at present;
secondly, selecting carrier liquid: according to different carrier liquids, the magnetic liquid is mainly divided into two categories of oil base and water base, a magnetic liquid is prepared, one category of carrier liquid is selected according to the function and the working environment of the magnetic liquid, the oil base magnetic liquid has strong magnetic property, large viscosity and good thermal stability, and is suitable formechanical sealing, mechanical lubrication and the like under high strength, and the water base magnetic liquid is widely applied to the biological and medical fields in recent years, including magnetic thermal therapy, magnetic targeting, magnetic slow release and the like;
selecting a surface modifier: based on different carrier liquids, corresponding water-soluble or water-insoluble surface modifiers are required to be selected, and in addition, the surface modifiers can meet the basic conditions of no toxicity, biocompatibility, biodegradability and the like for the water-based magnetic liquid applied to the fields of biology and medicine. The current commonly used macromolecules such as polysaccharide, protein, polyacrylic acid and the like and micromolecules such as amino acid, citric acid, folic acid and the like, the former has the main defects of too thick coating layer and low magnetic property, and the latter has the defects of poor dispersibility and easy agglomeration of nano particles.
Disclosure of Invention
The invention aims to provide a polymer modified water-based magnetic liquid with strong magnetic property and uniform dispersion by changing a surface modifier aiming at the defects of the existing magnetic liquid.
The invention also aims to provide a preparation method of the polymer modified water-based magnetic liquid.
The magnetic liquid is a stable colloid system formed by highly dispersing nano magnetic particles adsorbed with a surface modifier in a carrier liquid. Mainly comprises three parts of nano magnetic particles, a surface modifier and a carrier liquid. The invention discloses a polymer modified water-based magnetic liquid, wherein the material of nano magnetic particles is Fe3O4The surface modifier is straight-chain polyethyleneimine (L-PEI), the carrier liquid is water, and the polyethyleneimine modified water-based Fe is prepared3O4A magnetic liquid. The invention adopts the straight-chain polyethyleneimine as a shell part of a core-shell type nano magnetic dispersion medium in magnetic liquid, so that a new product is expected to serve as a gene vector, and simultaneously, the functions of magnetic targeting and magnetic slow release are increased, and the application of the magnetic liquid in the field of biomedicine is also widened.
The invention adopts a two-step method to prepare the water-based magnetic liquid, namely, the chemical coprecipitation method is firstly used for synthesizing the nano Fe3O4Magnetic particles, then adding straight-chain polyethyleneimine for modification, and preparing nano Fe by chemical coprecipitation method3O4The ion reaction equation for magnetic particles is:
the specific preparation scheme of the polymer modified water-based magnetic liquid is as follows:
(1) synthesis of nano-magnetic particles
Mixing Fe2+、Fe3+、OH-Solution mixing reaction, Fe2+、Fe3+、OH-The molar ratio of the Fe to the Fe is 1: 1.5-2: 8-16, stirring is carried out, the reaction temperature is 40-90 ℃, and the reaction time is 10-60 minutes, so that the nano Fe can be obtained3O4Magnetic particles;
(2) washing of nano-magnetic particles
Nano Fe obtained by the reaction in the step (1)3O4Repeatedly washing the magnetic particles with distilled water until the conductivity sigma of the washing liquid is less than or equal to 30 mu s/cm;
(3) preparation of nano magnetic particle sol
Adding distilled water into the nano Fe obtained by washing in the step (2)3O4Stirring and placing the magnetic particles in an ultrasonic disperser for ultrasonic dispersion for 5-10 min, then placing the magnetic particles on a magnetic seat for standing for 5-10 min, and collecting upper-layer stable sol; continuously adding distilled water, and repeating the steps to collect the sol until stable sol with stronger magnetism can not be obtained;
(4) modification of nano-magnetic particles
Taking nano Fe3O4Adjusting the pH value of a system to 8.5-10, adding straight-chain polyethyleneimine according to the molar ratio of N to Fe of 1-6: 1, stirring for 30-60 min, and reacting in a water bath at 50-90 ℃ to obtain the water-based magnetic liquid.
(5) Purification of water-based magnetic liquids
Washing the water-based magnetic liquid with distilled water, separating waste liquid from a product by using a magnetic base, placing the obtained water-based magnetic liquid in an ultrasonic disperser for re-ultrasonic dispersion for 20-30 min, and then performing centrifugal treatment (1000r/min, 30-60 min), wherein the upper-layer stable liquid is purified magnetic liquid;
the stirring speed in the step (1) is controlled to be 300-600 r/min, and the stirring speed in the step (4) is controlled to be 200-300 r/min.
The nano Fe obtained by the reaction in the step (1) can be obtained in the step (2)3O4The magnetic particles were washed with acetone solution and then with distilled water.
The preparation method also comprises a sixth step of concentrating the magnetic liquid, wherein the concentration is as follows: and (3) placing the magnetic liquid on a magnetic seat for sedimentation for 10-20 min, pouring out the supernatant, and then placing the magnetic liquid in an ultrasonic disperser for ultrasonic dispersion for 10-20 min to obtain the concentrated magnetic liquid.
Compared with the prior art, the invention has the following effects: the magnetic liquid prepared by the invention can be connected with DNA plasmids, and the saturation magnetization intensity can be measured by adopting a vibration sample magnetometer and can reach 2.5-3.3 emu/g; measuring the particle size of the magnetic particles by adopting TEM and XRD, wherein the average particle size of the magnetic particles is about 10 nm; the hydrodynamic radius is measured by using a laser light scattering instrument (PCS), the average hydrodynamic radius is about 50nm, and the hydrodynamic radius can be stabilized in a relatively large pH value range (3-11) and sufficiently meets the application condition of serving as a targeted gene vector. Meanwhile, the preparation method is simple and low in cost.
Drawings
FIG. 1 shows polyethyleneimine in nano Fe3O4Schematic diagram of adsorption structure on the surface of the particle;
FIG. 2 is a transmission electron micrograph of a magnetic liquid;
FIG. 3 is a hysteresis chart of a magnetic liquid;
fig. 4 is an infrared absorption spectrum of the magnetic liquid.
Detailed Description
Example 1
1. Preparation of Nano Fe3O4Magnetic particle sol
FeCl is added3Solution, FeCl2Mixing solution and strong ammonia water for reaction, Fe2+、Fe3+、OH-The mol ratio of the three is 1: 2: 16, stirring is carried out at the speed of 400r/min, the reaction temperature is stabilized at 60 ℃, and the reaction is carried out for 20 minutes to obtain the nano Fe3O4Magnetic particles; nano Fe obtained by the reaction3O4Washing the magnetic particles with a small amount of acetone solution for 1 time, and then repeatedly washing with distilled water until the conductivity sigma of the washing solution is 30 mus/cm; adding a certain amount of distilled water into the washed nano Fe3O4Stirring and placing the magnetic particles in an ultrasonic disperser for ultrasonic dispersion for 5 minutes, then placing the magnetic particles on a magnetic seat for standing for 6 minutes, and collecting upper-layer stable sol; continuously adding a certain amount of distilled waterRepeating the above steps to collect the sol until stable sol with stronger magnetism can not be obtained;
2. synthesis of magnetic liquids
Taking a certain volume of nano Fe with a certain mass concentration3O4And (2) adjusting the pH value to 9, placing the magnetic particle sol in a water bath kettle at 65 ℃, slowly adding 10% by mass of polyethyleneimine aqueous solution according to the molar ratio of N to Fe being 2 under the condition of stirring speed of 200r/min, reacting for 30min, washing the obtained magnetic liquid for 2 times, pouring off waste liquid, adding 30ml of water for dissolving, ultrasonically dispersing for 30min, centrifuging for 30min at 1000r/min, collecting the upper layer, namely the stable magnetic liquid, measuring the iron content of the stable magnetic liquid to be 5.134mg/ml, and measuring the saturationmagnetization to be 0.62 emu/g. L-PEI in nano Fe3O4The schematic diagram of the surface adsorption structure of the magnetic particles is shown in FIG. 1; the transmission electron micrograph of the magnetic liquid is shown in FIG. 2; fig. 3 and 4 are a hysteresis chart and an infrared spectrum of the magnetic liquid, respectively.
Example 2
1. Preparation of Nano Fe3O4Magnetic particle sol
FeCl is added3Solution, FeCl2Mixing solution and strong ammonia water for reaction, Fe2+、Fe3+、OH-The mol ratio of the three is 1: 1.5: 8, stirring is carried out at the speed of 300r/min, the reaction temperature is stabilized at 50 ℃, and the reaction is carried out for 40 minutes to obtain the nano Fe3O4Magnetic particles; nano Fe obtained by the reaction3O4Washing the magnetic particles with a small amount of acetone solution for 1 time, and then repeatedly washing with distilled water until the conductivity sigma of the washing solution is 25 mus/cm; adding a certain amount of distilled water into the washed nano Fe3O4Stirring and placing the magnetic particles in an ultrasonic disperser for ultrasonic dispersion for 10 minutes, then placing the magnetic particles on a magnetic seat for standing for 8 minutes, and collecting upper-layer stable sol; continuously adding a certain amount of distilled water, and repeating the steps to collect the sol until stable sol with stronger magnetism can not be obtained;
2. synthesis of magnetic liquids
Taking a certain volume of nano Fe with a certain mass concentration3O4Adjusting pH to 9.5, and mixing with magnetic particle solPlacing in a water bath kettle at about 65 ℃, slowly adding 10% polyethyleneimine water solution according to the molar ratio of N to Fe of 6: 1 under the condition of stirring speed of 200r/min, reacting for 30min, washing the obtained magnetic liquid for 2 times, pouring off the waste liquid, adding 30ml of water for dissolving, ultrasonically dispersing for 20min, centrifuging for 30min at 1000r/min, collecting the upper layer which is stable magnetic liquid, measuring the iron content of 5.435mg/ml, and the saturation magnetization of 0.67 emu/g.
Example 3
1. Preparation of Nano Fe3O4Magnetic particle sol
FeCl is added3Solution, FeCl2Mixing solution and strong ammonia water for reaction, Fe2+、Fe3+、OH-The mol ratio of the three is 1: 1.8: 10, stirring is carried out at the speed of 600r/min, the reaction temperature is stabilized at 90 ℃, and the reaction is carried out for 60 minutes to obtain the nano Fe3O4Magnetic particles; nano Fe obtained by the reaction3O4Washing the magnetic particles for 2 times by using a small amount of acetone solution, and then repeatedly washing by using distilled water until the conductivity sigma of the washing solution is 10 mu s/cm; adding a certain amount of distilled water into the washed nano Fe3O4Stirring and placing the magnetic particles in an ultrasonic disperser for ultrasonic dispersion for 8 minutes, then placing the magnetic particles on a magnetic seat for standing for 6 minutes, and collecting upper-layer stable sol; continuously adding a certain amount of distilled water, and repeating the steps to collect the sol until stable sol with stronger magnetism can not be obtained;
2. synthesis of magnetic liquids
Taking a certain volume of nano Fe with a certain mass concentration3O4The magnetic particle sol is adjusted to pH 10, and is placed in a water bath kettle at about 65 ℃, under the condition of stirring speed of 200r/min, polyethyleneimine water solution with the mass concentration of 10% is slowly added according to the molar ratio of N to Fe of 5: 1, after reaction for 60min, the obtained magnetic liquid is washed for 2 times, waste liquid is poured out, 30ml of water is added for dissolving, ultrasonic dispersion is carried out for 30min, centrifugation is carried out for 30min at 1000r/min, the upper layer is collected to be stable magnetic liquid, the iron content is measured to be 4.963mg/ml, and the saturation magnetization is 0.58emu/g。
Example 4
1. Preparation of Nano Fe3O4Magnetic particle sol
FeCl is added3Solution, FeCl2Mixing solution and strong ammonia water for reaction, Fe2+、Fe3+、OH-The mol ratio of the three is 1: 1.8: 10, stirring is carried out at the speed of 600r/min, the reaction temperature is stabilized at 90 ℃, and the reaction is carried out for 60 minutes to obtain the nano Fe3O4Magnetic particles; nano Fe obtained by the reaction3O4Washing the magnetic particles for 2 times by using a small amount of acetone solution, and then repeatedly washing by using distilled water until the conductivity sigma of the washing solution is 10 mu s/cm; adding a certain amount of distilled water into the washed nano Fe3O4Stirring and putting the magnetic particles in ultrasonic wavesUltrasonically dispersing for 8 minutes in a disperser, then placing on a magnetic seat, standing for 6 minutes, and collecting upper-layer stable sol; continuously adding a certain amount of distilled water, and repeating the steps to collect the sol until stable sol with stronger magnetism can not be obtained;
2.synthesis of magnetic liquids
Taking a certain volume of nano Fe with a certain mass concentration3O4And (2) adjusting the pH value of the magnetic particle sol to 10, placing the magnetic particle sol in a water bath kettle at about 65 ℃, slowly adding 10% by mass of polyethyleneimine aqueous solution according to the molar ratio of N to Fe of 5 to 1 under the condition of stirring speed of 200r/min, reacting for 60min, washing the obtained magnetic liquid for 2 times, pouring off waste liquid, adding 30ml of water for dissolving, ultrasonically dispersing for 30min, centrifuging for 30min at 1000r/min, collecting the upper layer, namely the stable magnetic liquid, measuring the iron content of the stable magnetic liquid to be 5.608mg/ml, and measuring the saturation magnetization to be 0.73 emu/g. And (3) placing the magnetic liquid on a magnetic seat for 20min, pouring out supernatant, and then placing the magnetic liquid in an ultrasonic disperser for ultrasonic dispersion for 30min to obtain the magnetic liquid with the iron content of 20mg/ml and the saturation magnetization of 3.3 emu/g.
Claims (7)
1. A polymer modified water-based magnetic liquid comprises nano magnetic particles, a surface modifier and a carrier liquid, and is characterized in that the surface modifier is straight-chain polyethyleneimine.
2. The polymer-modified water-based magnetic liquid as claimed in claim 1, wherein the nano-magnetic particles are nano-Fe3O4Magnetic particles, the carrier liquid being water.
3. A method for preparing the polymer modified water-based magnetic liquid as claimed in claim 1 or 2, which is characterized in that the method comprises the steps of preparing nano magnetic particle sol by a chemical coprecipitation method, and then carrying out surface modification by using straight-chain polyethyleneimine to obtain the polymer modified water-based magnetic liquid.
4. The method of claim 3, comprising the steps of:
(1) synthesis of nano-magnetic particles
Mixing Fe2+、Fe3+、OH-Solution mixing reaction, Fe2+、Fe3+、OH-The molar ratio of the Fe to the Fe is 1: 1.5-2: 8-16, stirring is carried out, the reaction temperature is 40-90 ℃, and the reaction time is 10-60 minutes, so that the nano Fe can be obtained3O4Magnetic particles;
(2) washing of nano-magnetic particles
Nano Fe obtained by the reaction in the step (1)3O4Repeatedly washing the magnetic particles with distilled water until the conductivity sigma of the washing liquid is less than or equal to 30 mu s/cm;
(3) preparation of nano magnetic particle sol
Adding distilled water into the nano Fe obtained by washing in the step (2)3O4Stirring and placing the magnetic particles in an ultrasonic disperser for ultrasonic dispersion for 5-10 min, then placing the magnetic particles on a magnetic seat for standing for 5-10 min, and collecting upper-layer stable sol; continuously adding distilled water, and repeating the steps to collect the sol until stable sol with stronger magnetism can not be obtained;
(4) modification of nano-magnetic particles
Taking nano Fe3O4Magnetic particle sol, adjusting system pHAnd (3) when the ratio is 8.5-10, adding straight-chain polyethyleneimine according to the molarratio of N to Fe of 1-6: 1, stirring for 30-60 min, and reacting in a water bath at 50-90 ℃ to obtain the water-based magnetic liquid.
(5) Purification of water-based magnetic liquids
Washing the water-based magnetic liquid with distilled water, separating waste liquid from a product by using a magnetic base, placing the obtained water-based magnetic liquid in an ultrasonic disperser for re-ultrasonic dispersion for 20-30 min, and then performing centrifugal treatment (1000r/min, 30-60 min), wherein the upper-layer stable liquid is purified magnetic liquid;
5. the process according to claim 4, wherein the stirring speed in the step (1) is controlled to 300 to 600r/min and the stirring speed in the step (4) is controlled to 200 to 300 r/min.
6. The method according to claim 4, wherein the nano Fe obtained by the reaction in step (1) is reacted in step (2)3O4The magnetic particles were washed with acetone solution and then with distilled water.
7. The method according to claim 4, 5 or 6, wherein the method further comprises concentrating the magnetic liquid, wherein the concentration is: and (3) placing the magnetic liquid on a magnetic seat for sedimentation for 10-20 min, pouring out the supernatant, and then placing the magnetic liquid in an ultrasonic disperser for ultrasonic dispersion for 10-20 min to obtain the concentrated magnetic liquid.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100449659C (en) * | 2006-07-28 | 2009-01-07 | 中国科学院广州能源研究所 | Water-based magnetic liquid of surface group rich, high stability and its preparation method |
| CN102502879A (en) * | 2011-11-02 | 2012-06-20 | 华东师范大学 | Fe3O4 nano-microsphere and preparation method thereof |
| CN103342392A (en) * | 2013-06-25 | 2013-10-09 | 升华集团德清华源颜料有限公司 | Magnetic black iron oxide |
| CN103426586A (en) * | 2013-07-31 | 2013-12-04 | 上海理工大学 | Method for preparing zinc ferrite water-based nanometer magnetic fluid |
| CN113299475A (en) * | 2021-05-31 | 2021-08-24 | 华中科技大学 | Water-based magnetofluid and in-situ growth preparation method and application thereof |
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2005
- 2005-10-14 CN CN 200510100277 patent/CN1747078A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100449659C (en) * | 2006-07-28 | 2009-01-07 | 中国科学院广州能源研究所 | Water-based magnetic liquid of surface group rich, high stability and its preparation method |
| CN102502879A (en) * | 2011-11-02 | 2012-06-20 | 华东师范大学 | Fe3O4 nano-microsphere and preparation method thereof |
| CN103342392A (en) * | 2013-06-25 | 2013-10-09 | 升华集团德清华源颜料有限公司 | Magnetic black iron oxide |
| CN103342392B (en) * | 2013-06-25 | 2015-11-18 | 升华集团德清华源颜料有限公司 | A kind of magnetic oxygenated iron oxide black |
| CN103426586A (en) * | 2013-07-31 | 2013-12-04 | 上海理工大学 | Method for preparing zinc ferrite water-based nanometer magnetic fluid |
| CN113299475A (en) * | 2021-05-31 | 2021-08-24 | 华中科技大学 | Water-based magnetofluid and in-situ growth preparation method and application thereof |
| CN113299475B (en) * | 2021-05-31 | 2022-05-31 | 华中科技大学 | Water-based magnetofluid and in-situ growth preparation method and application thereof |
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