CN100368463C - One-step synthesis of amphiphilic superparamagnetic submicron inorganic/polymer composite hollow spheres - Google Patents

Abstract

The present invention synthesizes ferrite/block polymer hybrid submicron hollow spheres in one step through solvothermal technology. The particle size of the superparamagnetic ferrite/block polymer hybrid submicron hollow spheres can be within 200 -800nm can be adjusted by simply controlling the reaction conditions (including reactant concentration and reaction time), and the particle size distribution is narrow, which can be dispersed in most polar and non-polar solvents. The resulting amphiphilic superparamagnetic ferrite/block polymer hybrid submicron hollow spheres have practical applications in microfluidic control, biological transplantation and separation, drug delivery, biosensing, clinical diagnosis and treatment, etc. Value. This method is simple and direct, low in cost, high in yield (>90%), non-toxic and readily available as a reaction raw material, and the product is a solid powder with stable properties and easy storage and transportation, and is suitable for industrial production.

Description

One-step synthesis of amphiphilic superparamagnetic submicron inorganic/polymer composite hollow spheres

technical field

The invention belongs to the field of preparation of magnetic materials, in particular to a preparation method of an inorganic substance/polymer composite material, in particular to a superparamagnetic ferrite/block polymer hybrid hybrid superparamagnetic ferrite with controllable particle size Preparation method of micron hollow spheres.

Background technique

Nanoscale to micron-scale hollow spheres with special structural, optical, magnetic and surface properties have become one of the hotspots of current scientific research because of their importance in scientific theory and potential application value in technology. Hollow structures are widely used in catalysts, fillers, cathode materials for lithium-ion batteries, biological transplantation and separation, drug delivery, sensing, and solar energy due to their special morphology and mechanical and chemical properties different from those of corresponding bulks. absorbent material, etc. Among them, the application in biological related fields is developing rapidly, including drug delivery, biological rapid separation technology and clinical diagnosis and treatment (especially cancer diagnosis and treatment). In the above-mentioned bio-related fields, the magnetic hollow spherical shells are required to be non-toxic, biocompatible, and capable of stably dispersing in liquid media, especially water, and most of them must be superparamagnetic. Among various magnetic hollow spherical shell materials, iron oxides (including Fe ₃ O ₄ and Y-Fe ₂ O ₃ ) and ferrite compounds MFe ₂ O ₄ (M=Co, Zn , Mn, Ni, etc.) hollow spherical shells have become a research hotspot because of their good stability and biocompatibility.

The traditional schemes for preparing hollow spherical shells are mainly divided into two categories: ①Using templates to prepare hollow structures ②Using self-assembly to prepare hollow structures. Scheme ① mostly uses "sacrificial" templates, including "hard" templates (such as polystyrene and silica microspheres) and "soft" templates (such as droplets, microemulsions, polymer capsules, and micelles) to prepare hollow ball). It specifically includes three steps: (1) preparing the required template with a certain surface modification by various methods; (2) coating the required spherical shell material on the prepared template by chemical deposition; (3) chemically engraving Etching, burning or other methods remove the template and give a hollow structure. Solution ② The method of preparing hollow structures by self-assembly is a very direct, effective, simple and economical method. However, there are not many methods for synthesizing hollow spherical shells, especially polymer/inorganic hollow spheres.

Among numerous nanometer and micrometer-scale hollow materials, inorganic/polymer composite hollow materials have wider application value than single inorganic or organic polymer hollow spherical shells. At present, the method of synthesizing inorganic/polymer composite hollow spherical shell materials mostly adopts the template method mentioned in scheme ①. Although this method is suitable for preparing hollow spherical shells with various chemical compositions, the experimental process is cumbersome, costly and The output is low, and some sophisticated equipment is sometimes required, which is not suitable for industrial production. A few of them prepare inorganic/polymer composite hollow spherical shells by self-assembly two-step method: one method is to prepare inorganic particles first and then self-assemble into hollow structures through specific surfactants or polymers: the other method is First, hollow polymer shells are formed by self-assembly, and then inorganic components are deposited on top. However, there are not many synthetic methods for preparing inorganic/polymer composite hollow spherical shells with specific functions (especially magnetic) conveniently and effectively and suitable for industrial production. Therefore, finding a method for preparing polymer/inorganic hollow spheres that is simple, high in yield, low in cost and suitable for industrial production has become an urgent problem to be solved.

Contents of the invention

The purpose of the present invention is to overcome the deficiency of the background technology and adopt a one-step method to synthesize submicron inorganic matter/block polymer composite hollow spheres with amphiphilicity and superparamagnetism.

In the present invention, ferric chloride and other metal chlorides and block polymers (PEO-PPO-PEO) are used as raw materials, and a compound with a hollow structure is synthesized in one step in an ethylene glycol system containing sodium acetate by solvothermal synthesis technology. Ferrite/block polymer hybrid submicron spheres.

The specific method of synthesizing ferrite/block polymer hybrid submicron hollow spheres is as follows:

1. Preparation of Fe3O4/block polymer hybrid submicron hollow spheres:

Dissolve ferric salt, sodium acetate (CH ₃ COONa), PEO-PPO-PEO (purchased from Aldrich Company) with a molecular weight between 1000 and 20000 in ethylene glycol solution and stir until uniform, ferric salt and acetic acid The molar ratio of sodium is 1:2~450, the concentration of ferric salt is 0.003~0.60M (mol/L), the concentration of PEO-PPO-PEO is 0.001~0.05M, and then put the solution into a stainless steel reaction kettle reaction at 200°C for 4 to 72 hours, and naturally cooled to room temperature; the obtained black product was separated by centrifugation or precipitation under the action of an external magnetic field, and then dispersed in absolute ethanol for cleaning, and this cycle was repeated 1 to 2 times, thereby Some ions, redundant polymers and other impurities on the surface are removed, and the obtained solid is vacuum-dried at room temperature to obtain ferric oxide/block polymer hybrid sub Black powder technique of micron hollow spheres.

2. Preparation of MFe ₂ O ₄ (M=Co, Mn)/block polymer hybrid submicron hollow spheres:

The preparation method is the same as the preparation method of ferric oxide/block polymer hybrid submicron hollow spheres, except that part of the ferric salt is replaced by a divalent salt of Co or Mn, and the ferric salt and the divalent salt of Co or Mn The molar ratio of the salt is 2:1, and the rest of the conditions are the same to obtain a black powder of MFe ₂ O ₄ (M=Co or Mn)/block polymer hybrid submicron hollow spheres with a particle size of 200-800 nm.

The preparation process of the present invention: for the preparation of ferric oxide/block polymer hybrid submicron hollow spheres, a part of ferric ions are reduced to ferrous ions in a reducing solvothermal system and combined with the remaining ferric ions Co-precipitation of iron ions produces ferric oxide nanoparticles, and the formed ferric oxide nanoparticles are self-assembled with block polymers to form hollow submicron spheres, and the two processes are carried out simultaneously. In the preparation of MFe ₂ O ₄ (M=Co, Mn)/block polymer hybrid submicron hollow spheres, divalent M ions directly co-precipitate with ferric ions to form MFe ₂ O ₄ nanoparticles, while MFe ₂ O ₄ Nanoparticles and block polymers self-assemble into hollow submicron spheres.

In the method of the present invention, the molecular weight of the block polymer used can be changed between 1000 and 20000; the ferric salt can be iron chloride (FeCl ₃ ·6H ₂ O), iron nitrate (Fe(NO ₃ ) ₃ 9H ₂ O) or iron sulfate (Fe ₂ (SO ₄ ) ₃ 6H ₂ O); the divalent salt of Co(Mn) can be cobalt dichloride (manganese dichloride), cobalt acetate (manganese acetate), Cobalt nitrate (manganese nitrate), cobalt sulfate (manganese sulfate).

The obtained product can be uniformly dispersed in most solvents, such as hexane, toluene, chloroform, methanol, acetonitrile, dimethyl sulfoxide, water, etc. A stable black suspension can be obtained in some solvents, such as ethanol, water and carbon disulfide, which can be stored stably for one week without precipitation. The solid powder obtained by drying the obtained solid under vacuum at room temperature can also be dispersed in most solvents without obvious agglomeration.

The invention synthesizes the ferrite/block polymer hybrid submicron hollow spheres in one step through the solvothermal technology. By simply controlling the reaction conditions (including reactant concentration and reaction time), the particle size of this superparamagnetic ferrite/block polymer hybrid submicron hollow sphere can be adjusted between 200-800nm, Moreover, the particle size distribution is narrow, and it can be dispersed in most polar and non-polar solvents. The method has the advantages of simplicity and directness, low cost, high yield (>90%), non-toxic and easy-to-obtain reaction raw materials, and the product is solid powder with stable properties and easy storage and transportation, and is suitable for industrial production. Moreover, the obtained amphiphilic superparamagnetic ferrite/block polymer hybrid submicron hollow spheres have great potential in microfluidic control, biological transplantation and separation, drug delivery, biosensing, clinical diagnosis and treatment, etc. practical application value.

Description of drawings

Figure 1: Scanning electron micrograph of cobalt ferrite/block polymer hybrid submicron hollow spheres;

Figure 2: Transmission electron micrograph of cobalt ferrite/block polymer hybrid submicron hollow spheres;

Figure 3: Powder X-ray diffraction spectrum of cobalt ferrite/block polymer hybrid submicron hollow spheres;

Figure 4: Hysteresis loops of cobalt ferrite/block polymer hybrid submicron hollow spheres at 4K and 300K;

Figure 5: Photographs of cobalt ferrite/block polymer hybrid submicron hollow spheres dispersed in various solvents.

Detailed ways

The present invention is further elaborated below in conjunction with embodiment.

Example 1:

35 mL of an ethylene glycol solution with a molar concentration of 0.57M FeCl ₃ ·6H ₂ O, 1.25M CH ₃ COONa and 0.0024M PEO-PPO-PEO (Aldrich, molecular weight: 14600) was stirred until homogeneous. Then put the solution into a 50 mL stainless steel reaction kettle with a polytetrafluoroethylene liner, react in an oven at 200° C. for 8 hours, and cool to room temperature naturally. The resulting black product can be separated by centrifugation (4000rpm) or precipitated and separated under the action of an external magnetic field (permanent magnet), and then dispersed in absolute ethanol for cleaning, so that it can be circulated for 1-2 times to remove some ions and excess polymerization on the surface. and other impurities were removed, and the resulting solid was vacuum-dried at room temperature to obtain a black powder of ferric oxide/block polymer hybrid submicron hollow spheres, with an average particle size of 400nm.

Example 2:

The experimental method is the same as in Example 1, except that the reaction ratio is different, and the concentration of FeCl ₃ 6H ₂ O is changed to 0.086M, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle size of 350nm .

Example 3:

The experimental method is the same as in Example 1, except that the reaction ratio is different, and the concentration of FeCl ₃ 6H ₂ O is changed to 0.029M, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle size of 300nm .

Example 4:

The experimental method was the same as that in Example 1, except that the concentration of FeCl ₃ ·6H ₂ O was changed to 0.003M, and ferric oxide/block polymer hybrid submicron hollow spheres were also obtained, with an average particle size of 250 nm.

Example 5:

The experimental method is the same as in Example 1, except that the molecular weight of PEO-PPO-PEO is changed from 14600 to 1900, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle size of 400nm.

Embodiment 6:

The experimental method is the same as in Example 1, except that the molecular weight of PEO-PPO-PEO is changed from 14600 to 5800, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle size of 400nm.

Embodiment 7:

The experimental method is the same as in Example 1, only the concentration of FeCl ₃ 6H ₂ O is changed to 0.4M, and the reaction time is changed to 72 hours, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 800nm.

Embodiment 8:

The experimental method is the same as in Example 1, only the concentration of FeCl ₃ 6H ₂ O is changed to 0.4M, and the reaction time is changed to 48 hours, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 680nm.

Embodiment 9:

The experimental method is the same as that in Example 1, only the concentration of FeCl ₃ 6H ₂ O is changed to 0.4M, and the reaction time is changed to 24 hours, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 600nm.

Example 10:

The experimental method is the same as that in Example 1, only the concentration of FeCl ₃ 6H ₂ O is changed to 0.4M, and the reaction time is changed to 12 hours, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 550nm.

Example 11:

The experimental method is the same as that in Example 1, only the concentration of FeCl ₃ 6H ₂ O is changed to 0.086M, and the reaction time is changed to 4 hours, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 200nm.

Example 12:

The experimental method is the same as that in Example 1, except that FeCl ₃ 6H ₂ O is replaced by Fe(NO ₃ ) ₃ 9H ₂ O, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 400nm.

Example 13:

The experimental method is the same as in Example 1, except that FeCl ₃ 6H ₂ O is replaced by Fe ₂ (SO ₄ ) ₃ 6H ₂ O, and ferric oxide/block polymer hybrid submicron hollow spheres are also obtained, with an average particle diameter of 400nm.

Example 14:

35 mL molar concentrations of 0.14M FeCl ₃ 6H ₂ O, 0.07M CoCl ₂ 4H ₂ O, 1.25M CH ₃ COONa and 0.0024M PEO-PPO-PEO (Aldrich, molecular weight: 1900) in B The diol solution was stirred until homogeneous. Then put the solution into a 50 mL stainless steel reaction kettle with a polytetrafluoroethylene liner, react in an oven at 200° C. for 8 hours, and cool to room temperature naturally. The resulting black product can be separated by centrifugation or precipitation under the action of an external magnetic field, and then dispersed in absolute ethanol for cleaning. This cycle is repeated 1-2 times to remove some ions, excess polymers and other impurities on the surface, and The resulting solid was vacuum dried at room temperature to obtain a solid powder.

The structures and properties of the cobalt ferrite/block polymer hybrid submicron hollow spheres prepared in this example were characterized. The scanning electron microscope characterization of cobalt ferrite/block polymer hybrid submicron hollow spheres is shown in Figure 1, and the transmission electron microscope characterization of cobalt ferrite/block polymer hybrid submicron hollow spheres is shown in Figure 2. 1 and Figure 2, it can be confirmed that the obtained ball is a hollow spherical shell with an average particle size of 200nm, and the particle size is almost monodisperse, and the spherical shell is formed by embedding inorganic nanoparticles in a block polymer. The inorganic composition in the spherical shell of cobalt ferrite/block polymer hybrid submicron hollow spheres can be determined as CoFe ₂ O ₄ (JCPDS 03-0864) by its powder X-ray diffraction spectrum, and in the characteristic peak diffraction peak (30.0°, 35.4°, 43.0°, 53.4°, 56.9°, and 62.5°) have obvious broadening, indicating that the particles are very small and are nanoscale, as shown in Figure 3. The magnetic characterization of the cobalt ferrite/block polymer hybrid submicron hollow spheres is shown in Figure 4, and the hysteresis loops at temperatures of 4K and 300K can be determined to be superparamagnetic. Figure 5 is the ultrasonic diffusion of solid powder of cobalt ferrite/block polymer hybrid submicron hollow spheres in (from left to right) n-hexane, toluene, chloroform, methanol, acetonitrile, dimethyl sulfoxide, water , this phenomenon of being well dispersed in both water and oil phase indicates that the product has good amphiphilic properties and excellent dispersibility.

Example 15:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M Co(CH ₃ COO) ₂ ·4H ₂ O, and the cobalt ferrite/block polymer hetero Submicron hollow spheres with an average particle size of 200nm.

Example 16:

The experimental method is the same as in Example 12, except that CoCl ₂ ·4H ₂ O with a concentration of 0.07M is replaced with Co(NO ₃ ) ₂ ·6H ₂ O with a concentration of 0.07M, and cobalt ferrite/block polymer hybrid Submicron hollow spheres with an average particle size of 200nm.

Example 17:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M CoSO ₄ ·7H ₂ O, and cobalt ferrite/block polymer hybrid submicron hollow spheres are also obtained , the average particle size is 200nm.

Example 18:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M MnCl ₂ ·4H ₂ O, and manganese ferrite/block polymer hybrid submicron hollow spheres are also obtained , the average particle size is 400nm.

Example 19:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M Mn(CH ₃ COO) ₂ ·4H ₂ O, and the manganese ferrite/block polymer hetero Submicron hollow spheres with an average particle size of 400nm.

Example 20:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M Mn(NO ₃ ) ₂ ·6H ₂ O, and the manganese ferrite/block polymer hybrid Submicron hollow spheres with an average particle size of 400nm.

Example 21:

The experimental method is the same as in Example 12, except that the concentration of 0.07M CoCl ₂ ·4H ₂ O is replaced by the concentration of 0.07M MnSO ₄ ·H ₂ O, and manganese ferrite/block polymer hybrid submicron hollow spheres are also obtained , the average particle size is 400nm.

Claims (5)

1. One-step method for synthesizing amphiphilic superparamagnetic submicron inorganic/polymer composite hollow spheres, the steps are: dissolving ferric salt, sodium acetate, and PEO-PPO-PEO with a molecular weight between 1000 and 20000 Stir in ethylene glycol solution until uniform, the molar ratio of ferric salt and sodium acetate is 1:2~450, the concentration of ferric salt is 0.003~0.60mol/L, and the concentration of PEO-PPO-PEO is 0.001 ~0.05mol/L, then put the solution into a stainless steel reactor, react at 200°C for 4-72 hours, and cool to room temperature naturally; the obtained black product is separated by centrifugation or precipitation under the action of an external magnetic field, and then dispersed in Wash in absolute ethanol, and cycle like this for 1 to 2 times, so as to remove some ions, redundant polymers and other impurities on the surface, and dry the obtained solid in vacuum at room temperature to obtain a particle size of 200-800nm Black powder between Fe3O4/block polymer hybrid submicron hollow spheres. 2. The method for synthesizing amphiphilic superparamagnetic submicron inorganic matter/polymer composite hollow spheres in one step as claimed in claim 1, wherein the ferric salt is ferric chloride, ferric nitrate or ferric sulfate. 3. the method for the submicron inorganic substance/polymer composite hollow sphere of amphiphilic superparamagnetic synthesis of one-step method as claimed in claim 1, it is characterized in that: replace part ferric salt with the divalent salt of Co or Mn, make The molar ratio of the ferric salt to the divalent salt of Co or Mn is 2:1, and the black powder of MFe ₂ O ₄ /block polymer hybrid submicron hollow spheres with a particle size of 200-800nm is obtained, wherein M is Co or Mn. 4. the method for synthesizing the submicron inorganic substance/polymer composite hollow sphere of amphiphile superparamagnetic in one step as claimed in claim 3, it is characterized in that: the divalent salt of Co is cobalt dichloride, cobalt acetate, cobalt nitrate or cobalt sulfate. 5. the method for synthesizing the submicron inorganic matter/polymer composite hollow sphere of amphiphile superparamagnetic in one step as claimed in claim 3, it is characterized in that: the divalent salt of Mn is manganese dichloride, manganese acetate, manganese nitrate or manganese sulfate.

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