Magnetic polystyrene microspheres, and preparation method and application thereof

Abstract

The application provides a kind of magnetic polystyrene microspheres and its preparation method and application, the preparation raw material of the magnetic polystyrene microspheres includes the combination of oleic acid modified ferroferric oxide magnetic nanoparticle, compound emulsifier, initiator, crosslinking agent, styrene monomer, acrylic acid monomer and methyl methacrylate monomer;The magnetic polystyrene microspheres provided by the application are matched with each other by selecting the above raw materials, and the preparation process of microfluidic is selected, so that the magnetic polystyrene microspheres prepared have the advantages of adjustable particle size and superior monodispersity, can be used as the building unit for preparing photonic crystal materials, and have the characteristics of corresponding photonic crystal and magnetic driving performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer microsphere technology, specifically relating to a magnetic polystyrene microsphere, its preparation method, and its application. Background Technology

[0002] As we all know, materials are one of the three pillars of modern science and technology. Among them, polymer microspheres are a dynamic newcomer in the field of materials science. With their advantages of abundant raw material sources, diverse types, and wide range of functions, they have not only become special functional materials for developing high-tech new materials and meeting various special applications, but are also widely used in various fields of high-tech advanced technology, national defense construction, and the national economy, becoming an indispensable material in people's social life.

[0003] Polymer microspheres range in diameter from nanometers to micrometers and come in spherical or other geometric shapes, including solid, hollow, and porous forms. Different types of polymer microspheres can be selected according to actual needs. Polymer microspheres can serve not only as micro-storage devices and microreactors but also as micro-separators and microstructural units, endowing microsphere materials with different physical and chemical properties and expanding their application fields. Based on their function, polymer microspheres can be classified into microcapsules, composite microspheres, magnetic microspheres, and conductive microspheres. Among them, magnetic polymer microspheres not only possess many of the properties of polymer microspheres but also exhibit magnetic responsiveness, enabling rapid separation and localization under an applied magnetic field. Different functional groups are introduced onto the surface of polymer microspheres through polymerization reactions, endowing them with different functions. Magnetic polymer microspheres can bind to drugs, enzymes, antigens, antibodies, various target cells, DNA or RNA, metal particles, and organic matter. They are firmly bound to the surface of magnetic metal oxide crystals by van der Waals forces, hydrogen bonds, coordination bonds, and intermolecular electrostatic interactions, forming a solid spherical structure. Therefore, magnetic polymer microspheres have broad application prospects in targeted drugs, enzyme immobilization, rapid cell separation, and biomedicine.

[0004] Fe3O4 magnetic nanoparticles or magnetic fluids are preferred materials for magnetic polymer microspheres due to their simple preparation process, stable properties, strong magnetic responsiveness, high particle purity, and the fact that they do not cause poisoning when injected into the body. CN103223322A discloses a method for preparing magnetic microspheres co-modified with silver nanoparticles and thiol groups, including the following steps: (1) preparation of Fe3O4 magnetic microspheres; (2) preparation of Fe3O4 magnetic microspheres coated with SiO2; (3) preparation of Fe3O4 magnetic microspheres coated with thiol-modified SiO2; (4) preparation of Fe3O4 magnetic microspheres coated with silver nanoparticles and thiol-modified SiO2. This invention uses a silane coupling agent to coat nano-Fe3O4, utilizing the safety and stability of silicon dioxide to improve its stability and acid and alkali resistance; and introduces functional thiol groups on its surface through chemical reaction to obtain a novel modified magnetic nanoparticle. However, this preparation method is relatively complex, and the size of the microspheres obtained after further preparation is not adjustable and the dispersibility is poor, which is not conducive to rapid industrialization.

[0005] Therefore, developing a magnetic polystyrene microsphere with adjustable size and excellent monodispersity is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a magnetic polystyrene microsphere, its preparation method, and its application. Through the specific selection of raw materials and the microfluidic preparation process, the final magnetic polystyrene microspheres possess the characteristics of adjustable particle size and superior monodispersity. They can be used as building blocks for preparing photonic crystal materials and possess the characteristics and magnetic driving performance of corresponding photonic crystals.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a magnetic polystyrene microsphere, wherein the raw materials for preparing the magnetic polystyrene microsphere include oleic acid modified iron oxide magnetic nanoparticles, a compound emulsifier, an initiator, a crosslinking agent, a styrene monomer, an acrylic monomer, and a methyl methacrylate monomer.

[0009] The magnetic polystyrene microspheres provided by this invention are prepared from a combination of oleic acid-modified iron oxide magnetic nanoparticles, a compound emulsifier, an initiator, a crosslinking agent, styrene monomer, acrylic monomer, and methyl methacrylate monomer. By selecting the combination of the above-mentioned raw materials, the magnetic polystyrene microspheres prepared can have the characteristics of adjustable particle size and excellent monodispersity.

[0010] Preferably, the oleic acid-modified iron oxide magnetic nanoparticles have a particle size of 5–20 nm, such as 7 nm, 9 nm, 11 nm, 13 nm, 15 nm, 17 nm, or 19 nm.

[0011] Preferably, the compound emulsifier comprises a combination of sodium dodecylbenzenesulfonate and emulsifier CO897.

[0012] Preferably, the mass ratio of sodium dodecylbenzenesulfonate to emulsifier CO897 is (0.25-0.5):1, for example, 0.27:1, 0.29:1, 0.31:1, 0.33:1, 0.35:1, 0.37:1, 0.39:1, 0.41:1, 0.43:1, 0.45:1, or 0.47:1, etc.

[0013] As a preferred embodiment of the present invention, the advantage of selecting sodium dodecylbenzenesulfonate and emulsifier CO897 in a mass ratio of (0.25-0.5):1 is that this compound emulsifier establishes a balance between electrostatic force and diffusion force. Because latex particles carry an electric charge on their surface, there is an electrostatic repulsion between them, and the closer they are, the greater the repulsion, making it difficult for latex particles to approach and preventing aggregation, thus ensuring high stability of the emulsion. If only sodium dodecylbenzenesulfonate is selected as the emulsifier, this anionic emulsifier will cause the electrostatic force and diffusion force to be unable to reach a balance, resulting in reduced emulsion stability; similarly, if only emulsifier CO897 is selected as the emulsifier, it will also cause emulsion instability.

[0014] Preferably, the initiator comprises potassium persulfate.

[0015] Preferably, the crosslinking agent comprises N,N'-methylenebisacrylamide.

[0016] Preferably, the raw materials for preparing the magnetic polystyrene microspheres also include buffer solution and / or solvent.

[0017] Preferably, the buffer solution comprises sodium bicarbonate buffer solution.

[0018] Preferably, the solvent includes deionized water.

[0019] Preferably, the magnetic polystyrene microspheres have a particle size of 160–320 nm, such as 180 nm, 200 nm, 220 nm, 240 nm, 260 nm, 280 nm, or 300 nm.

[0020] In a second aspect, the present invention provides a method for preparing magnetic polystyrene microspheres as described in the first aspect, the method comprising the following steps:

[0021] (1) Oleic acid-modified iron oxide magnetic nanoparticles, compound emulsifier, initiator and optionally buffer solution are mixed in a solvent to obtain pre-emulsified solution A; initiator, crosslinking agent, styrene monomer, acrylic monomer and methyl methacrylate monomer are mixed in a solvent to obtain pre-emulsified solution B;

[0022] (2) The pre-emulsified solution A and pre-emulsified solution B obtained in step (1) are placed on a microfluidic pump and reacted step by step to obtain the magnetic polystyrene microspheres.

[0023] The preparation method provided by this invention first prepares pre-emulsion solution A and pre-emulsion solution B, respectively. Then, the obtained pre-emulsion solution A and pre-emulsion solution B are gradually brought into contact on a microfluidic pump to react. The flow rates of pre-emulsion solution A and pre-emulsion solution B can be effectively controlled, so that the two come into contact and react within a suitable range. Finally, magnetic polystyrene microspheres with adjustable size are prepared. The microfluidic emulsion polymerization method has the advantages of fast polymerization speed, good dispersibility, easy mixing and heat transfer, no need for nitrogen protection, water as solvent during polymerization, no pollution, and simple and convenient post-processing.

[0024] Preferably, the oleic acid modified iron oxide magnetic nanoparticles in the pre-emulsified solution A in step (1) have a mass percentage content of 0.5% to 1%, such as 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, or 0.95%.

[0025] Preferably, the mass percentage of the compound emulsifier in the pre-emulsified solution A in step (1) is 0.1% to 0.3%, for example, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, or 0.28%.

[0026] Preferably, the mass percentage of the initiator in the pre-emulsified solution A in step (1) is 0.05-0.15%, for example, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, or 0.14%.

[0027] Preferably, the mass percentage of buffer solution in the pre-emulsified solution A in step (1) is 0.3-0.5%, for example, 0.32%, 0.34%, 0.36%, 0.38%, 0.4%, 0.42%, 0.44%, 0.46%, or 0.48%.

[0028] Preferably, the oleic acid-modified iron oxide magnetic nanoparticles, compound emulsifier, initiator, and optionally buffer solution are mixed in a solvent under ultrasonic conditions.

[0029] Preferably, the ultrasound duration is 30 to 60 minutes, such as 35 minutes, 40 minutes, 45 minutes, 50 minutes, or 55 minutes.

[0030] Preferably, the pre-emulsified solution A in step (1) is placed in syringe A for later use.

[0031] Preferably, the volume of syringe A is 100-150 mL, such as 105 mL, 110 mL, 115 mL, 120 mL, 125 mL, 130 mL, 135 mL, 140 mL or 145 mL.

[0032] Preferably, the initiator in the pre-emulsified solution B in step (1) has a mass percentage content of 0.5% to 1%, such as 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9% or 0.95%.

[0033] Preferably, the mass percentage of the crosslinking agent in the pre-emulsified solution B in step (1) is 0.1% to 0.2%, for example, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, or 0.19%.

[0034] Preferably, the mass percentage of styrene monomer in the pre-emulsified solution B in step (1) is 70-90%, such as 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, or 88%.

[0035] Preferably, the mass percentage of acrylic monomer in the pre-emulsified solution B in step (1) is 5% to 15%, such as 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, or 14%.

[0036] Preferably, the mass percentage of methyl methacrylate monomer in the pre-emulsified solution B in step (1) is 5% to 15%, such as 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, or 14%.

[0037] Preferably, step (1) involves mixing the initiator, crosslinking agent, styrene monomer, acrylic monomer, and methyl methacrylate monomer in a solvent under stirring conditions.

[0038] Preferably, the stirring time is 6 to 8 hours, such as 6.2 hours, 6.4 hours, 6.6 hours, 6.8 hours, 7 hours, 7.2 hours, 7.4 hours, 7.6 hours, or 7.8 hours.

[0039] Preferably, the pre-emulsified solution B described in step (1) is placed in syringe B for later use.

[0040] Preferably, the volume of syringe B is 10-20 mL, such as 11 mL, 12 mL, 13 mL, 14 mL, 15 mL, 16 mL, 17 mL, 18 mL or 19 mL.

[0041] Preferably, the reaction temperature in step (2) is 70-80°C, for example 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C or 79°C.

[0042] Preferably, the reaction time in step (2) is 2 to 5 minutes, such as 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes or 4.5 minutes.

[0043] Preferably, the reaction in step (2) specifically includes: connecting syringe A containing pre-emulsified solution A and syringe B containing pre-emulsified solution B to the two inlets of the Y-type microfluidic chip of the microfluidic pump through pipes, and connecting the outlet of the Y-type microfluidic chip through pipes, adjusting the flow rates of pre-emulsified solution A and pre-emulsified solution B so that they come into contact and react to obtain the magnetic polystyrene microspheres.

[0044] Preferably, the pipe is a polytetrafluoroethylene (PTFE) pipe.

[0045] Preferably, the inner diameter of the polytetrafluoroethylene pipe is 0.5 to 1 mm, such as 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm or 0.95 mm.

[0046] Preferably, the outer diameter of the polytetrafluoroethylene pipe is 0.8 to 1.3 mm, such as 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm or 1.25 mm.

[0047] Preferably, the inner diameter of the channel in the Y-shaped microfluidic chip is 0.3 to 0.6 mm, such as 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm or 0.55 mm.

[0048] Preferably, the outer diameter of the channel inside the Y-shaped microfluidic chip is 0.5 to 1 mm, such as 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, or 0.95 mm.

[0049] Preferably, the flow rate of the pre-emulsified solution A is 10-15 mL / h, for example, 10.5 mL / h, 11 mL / h, 11.5 mL / h, 12 mL / h, 12.5 mL / h, 13 mL / h, 13.5 mL / h, 14 mL / h or 14.5 mL / h.

[0050] Preferably, the flow rate of the pre-emulsified solution B is 1 to 2 mL / h, for example, 1.1 mL / h, 1.2 mL / h, 1.3 mL / h, 1.4 mL / h, 1.5 mL / h, 1.6 mL / h, 1.7 mL / h, 1.8 mL / h or 1.9 mL / h.

[0051] Preferably, the flow rate of the preemulsified solution A is 7.5 to 10 times that of the preemulsified solution B, for example, 7.7 times, 7.9 times, 8.1 times, 8.3 times, 8.5 times, 8.7 times, 8.9 times, 9.1 times, 9.3 times, 9.5 times, or 9.7 times.

[0052] As a preferred technical solution of the present invention, limiting the flow rate of pre-emulsified solution A to 7.5 to 10 times that of pre-emulsified solution B has the advantage of ensuring that pre-emulsified solutions A and B react completely, and that the solutions prepared by A and B finish reacting simultaneously. This also ensures that monomers react gently with an appropriate amount of initiator, avoiding the characteristics of rapid polymerization. On the one hand, if the flow rate of pre-emulsified solution A is relatively fast, a large portion of the liquid in pre-emulsified solution A will not have time to react completely with pre-emulsified solution B, resulting in low reaction efficiency. On the other hand, if the flow rate of pre-emulsified solution A is relatively slow, the initiator in phase B may exacerbate the reaction process, potentially leading to rapid polymerization and emulsion aggregation. Therefore, this reaction results in an emulsion with good stability, low viscosity, easy heat dissipation, and easy control of the reaction process.

[0053] Preferably, after the reaction in step (2) is completed, the steps of cooling and washing are also included.

[0054] Preferably, the cooling temperature is room temperature.

[0055] Preferably, the washing includes a combination of hydrochloric acid solution washing and centrifugal washing.

[0056] Preferably, the washing time with hydrochloric acid solution is 24 to 48 hours, such as 27 hours, 30 hours, 33 hours, 36 hours, 39 hours, 42 hours, or 45 hours.

[0057] Preferably, the molar concentration of hydrochloric acid in the hydrochloric acid solution is 0.5 to 1.5 mol / L, such as 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, or 1.4 mol / L.

[0058] Preferably, the centrifugal washing speed is 10000-14000 rad / min, such as 10500 rad / min, 11000 rad / min, 11500 rad / min, 12000 rad / min, 12500 rad / min, 13000 rad / min or 13500 rad / min.

[0059] Preferably, the centrifugal washing is performed 3 to 5 times, for example, 4 times.

[0060] Preferably, the centrifugal washing includes a combination of centrifugal washing with anhydrous ethanol and centrifugal washing with deionized water.

[0061] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0062] (1) Under ultrasonic conditions, oleic acid modified iron oxide magnetic nanoparticles, compound emulsifier, initiator and optional buffer are mixed in a solvent for 30-60 min to obtain pre-emulsion solution A. The obtained pre-emulsion solution A is placed in syringe A with a volume of 100-150 mL for later use. Under stirring conditions, initiator, crosslinking agent, styrene monomer, acrylic monomer and methyl methacrylate monomer are mixed in a solvent for 6-8 h to obtain pre-emulsion solution B. The obtained pre-emulsion solution B is placed in syringe B with a volume of 10-20 mL for later use.

[0063] (2) The pre-emulsified solution A and pre-emulsified solution B obtained in step (1) are respectively connected to the two inlets of the Y-type microfluidic chip of the microfluidic pump through polytetrafluoroethylene (PTFE) pipes, and the outlet end of the Y-type microfluidic chip is connected with PTFE pipes. The flow rate of pre-emulsified solution A is adjusted to 10-15 mL / h and the flow rate of pre-emulsified solution B is adjusted to 1-2 mL / h. The two are brought into contact and reacted at 70-80℃ for 2-5 min. After cooling to room temperature, the solution is washed with hydrochloric acid solution with a molar concentration of 0.5-1.5 mol / L for 24-48 h. The solution is then centrifuged with anhydrous ethanol at a speed of 10000-14000 rad / min and centrifuged with deionized water at a speed of 10000-14000 rad / min to obtain the magnetic polystyrene microspheres.

[0064] Thirdly, the present invention provides an application of magnetic polystyrene microspheres as described in the first aspect in biomedicine.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The raw materials for preparing magnetic polystyrene microspheres provided by the present invention include oleic acid modified iron oxide magnetic nanoparticles, compound emulsifiers, initiators, crosslinking agents, styrene monomers, acrylic monomers and methyl methacrylate monomers. By selecting the above raw materials for preparation and matching, the magnetic polystyrene microspheres prepared have the characteristics of adjustable particle size and excellent monodispersity. They can be used as building blocks for preparing photonic crystal materials and have the characteristics of corresponding photonic crystals and magnetic driving performance.

[0067] (2) The present invention prepares magnetic polystyrene microspheres by selecting a microfluidic preparation process. The preparation method uses simple equipment, is easy to operate, does not require nitrogen protection, has good repeatability, and the product surface is clean and does not require complicated post-processing. Attached Figure Description

[0068] Figure 1 The image is a scanning electron microscope image of the magnetic polystyrene microspheres prepared in Example 1 at 20K, with a scale bar of 500 nm.

[0069] Figure 2 The image shows a scanning electron microscope image of the magnetic polystyrene microspheres prepared in Example 1 at 40K, with a scale bar of 200 nm. Detailed Implementation

[0070] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0071] Example 1

[0072] A magnetic polystyrene microsphere is prepared by the following steps:

[0073] (1) Place 0.5g of oleic acid modified iron(III) oxide (Fe3O4) magnetic nanoparticles (average particle size of 5nm), 0.02g of emulsifier sodium dodecylbenzenesulfonate (SDBS), 0.08g of emulsifier CO897, 0.3g of sodium bicarbonate, 0.05g of potassium persulfate (KPS) and 99.05g of distilled water into a beaker and ultrasonically disperse for 30min to form a pre-emulsion solution A. Then inject the pre-emulsion solution A into a 100mL syringe and remove the air from the syringe A for later use. Dissolve 0.05g of KPS, 0.01g of N,N'-methylenebisacrylamide (MBA), 7g of monomer styrene (St), 1.5g of monomer acrylic acid (AA) and 1.5g of monomer methyl methacrylate (MMA) by magnetic stirring for 7h to obtain a pre-emulsion solution B. Inject the pre-emulsion solution B into a 10mL syringe B and remove the air from the syringe for later use.

[0074] (2) Fix syringe A containing pre-emulsified solution A and syringe B containing pre-emulsified solution B obtained in step (1) onto a microfluidic pump. Then, connect the two syringes to the two inlets of a Y-shaped serpentine channel microfluidic chip with dimensions of 6×4×2.5cm, an inner channel size of 0.3mm, and an outer channel size of 0.5mm, respectively, through a polytetrafluoroethylene tube with an inner diameter of 0.5mm and an outer diameter of 0.8mm. Then, connect the outlet end of the Y-shaped chip with a polytetrafluoroethylene tube of the same inner diameter. Finally, place the microfluidic chip in an oil bath at 70℃ and adjust the flow rate of pre-emulsified solution A to 10mL / h. The flow rate of emulsion solution B was adjusted to 1 mL / h to allow the two pre-emulsion solutions to mix thoroughly and uniformly within the Y-shaped serpentine channel chip and undergo emulsion polymerization for 2 min. After the emulsification reaction was completed, the obtained magnetic polystyrene microsphere emulsion was cooled to room temperature. Then, the magnetic polystyrene microsphere emulsion was poured into a 0.5 mol / L hydrochloric acid solution and washed for 24 h to remove uncoated magnetic nanoparticles. The microspheres were then washed three times by centrifugation with anhydrous ethanol and distilled water, respectively, at a speed of 14000 rad / min. Finally, pure magnetic polystyrene microspheres with an average particle size of 210 nm were obtained.

[0075] Example 2

[0076] A magnetic polystyrene microsphere is prepared by the following steps:

[0077] (1) Place 0.75g of oleic acid modified Fe3O4 magnetic nanoparticles (average particle size of 10nm), 0.06g of SDBS, 0.14g of emulsifier CO897, 0.5g of sodium bicarbonate, 0.1g of KPS and 98.45g of distilled water into a beaker and ultrasonically disperse for 45min to form a pre-emulsion solution A. Then inject the pre-emulsion solution A into a 150mL syringe A and remove the air from the syringe A for later use. Dissolve 0.075g of KPS, 0.015g of MBA, 15g of monomer St, 2.5g of monomer AA and 2.5g of monomer MMA by magnetic stirring for 8h to obtain a pre-emulsion solution B. Inject the dissolved pre-emulsion solution B into a 20mL syringe B and remove the air from the syringe for later use.

[0078] (2) Fix syringe A containing pre-emulsified solution A and syringe B containing pre-emulsified solution B obtained in step (1) onto a microfluidic pump. Then, connect the two syringes to the two inlets of a Y-shaped serpentine channel microfluidic chip with an inner diameter of 0.75 mm and an outer diameter of 1 mm through a polytetrafluoroethylene tube. The two syringes are 6×4×2.5 cm in size, with an inner channel size of 0.5 mm and an outer channel size of 0.7 mm. Then, connect the outlet end of the Y-shaped chip with a polytetrafluoroethylene tube of the same inner diameter. Finally, place the serpentine channel microfluidic chip in an oil bath at 75°C and adjust the flow rate of pre-emulsified solution A to 12 mL. The flow rate of pre-emulsified solution B was adjusted to 1.5 mL / h, allowing the two pre-emulsified solutions to mix thoroughly and uniformly within the Y-shaped serpentine channel chip and undergo emulsion polymerization for 4 min. After the emulsification reaction was completed, the obtained magnetic polystyrene microsphere emulsion was cooled to room temperature. Then, the magnetic polystyrene microsphere emulsion was poured into a 1 mol / L hydrochloric acid solution and washed for 30 h to remove uncoated magnetic nanoparticles. The microspheres were then washed four times by centrifugation with anhydrous ethanol and distilled water, respectively, at a speed of 10000 rad / min. Finally, pure magnetic polystyrene microspheres with an average particle size of 260 nm were obtained.

[0079] Example 3

[0080] A magnetic polystyrene microsphere is prepared by the following steps:

[0081] (1) 1g of oleic acid modified Fe3O4 magnetic nanoparticles (average particle size of 20nm), 0.1g of SDBS, 0.2g of emulsifier CO897, 0.5g of buffer sodium bicarbonate, 0.15g of KPS and 98.05g of distilled water were placed in a beaker and ultrasonically dispersed for 60min to form a pre-emulsion solution A. The pre-emulsion solution A was then injected into a 150mL syringe A and the air in syringe A was purged for later use. 0.1g of KPS, 0.02g of MBA, 9g of monomer St, 0.5g of monomer AA and 0.5g of monomer MMA were fully dissolved by magnetic stirring for 6h to obtain an emulsion solution B. The dissolved pre-emulsion solution B was injected into a 20mL syringe B and the air in syringe was purged for later use.

[0082] (2) Fix syringe A containing pre-emulsified solution A and syringe B containing pre-emulsified solution B obtained in step (1) onto a microfluidic pump. Then, connect the two syringes to the two inlets of a Y-shaped serpentine channel microfluidic chip with an inner diameter of 1 mm and an outer diameter of 1.3 mm, respectively, through a polytetrafluoroethylene tube. The chip has a size of 6×4×2.5 cm, an inner channel size of 0.6 mm, and an outer channel size of 1 mm. Then, connect the outlet end of the Y-shaped chip with a polytetrafluoroethylene tube of the same inner diameter. Finally, place the serpentine channel microfluidic chip in an oil bath at 80°C and adjust the flow rate of pre-emulsified solution A to 15 mL / h. The flow rate of pre-emulsified solution B was adjusted to 2 mL / h to allow the two pre-emulsified solutions to mix thoroughly and uniformly within the Y-shaped serpentine channel chip and undergo emulsion polymerization for 5 min. After the emulsification reaction was completed, the obtained magnetic polystyrene microsphere emulsion was cooled to room temperature. Then, the magnetic polystyrene microsphere emulsion was poured into a 1.5 mol / L hydrochloric acid solution and washed for 48 h to remove uncoated magnetic nanoparticles. The microspheres were then washed five times by centrifugation with anhydrous ethanol and distilled water at a speed of 10,000 rad / min. Finally, pure magnetic polystyrene microspheres with an average particle size of 320 nm were obtained.

[0083] Example 4

[0084] A magnetic polystyrene microsphere differs from Example 1 only in that the amount of sodium dodecylbenzenesulfonate added is 0.03g and the amount of emulsifier CO897 added is 0.07g. The other components, amounts, and preparation methods are the same as in Example 1.

[0085] Example 5

[0086] A magnetic polystyrene microsphere differs from Example 1 only in that the amount of sodium dodecylbenzenesulfonate added is 0.04 g and the amount of emulsifier CO897 added is 0.06 g, while the other components, amounts, and preparation methods are the same as in Example 1.

[0087] Comparative Example 1

[0088] A magnetic polystyrene microsphere, differing from Example 1 only in that Example 1 uses microfluidic emulsion polymerization, while this Comparative Example 1 uses conventional emulsion polymerization with a polymerization reaction time of 6 hours, but without nitrogen gas; its specific preparation method includes the following steps:

[0089] (1) 0.5g of oleic acid modified iron(III) oxide (Fe3O4) magnetic nanoparticles (average particle size of 5nm), 0.02g of emulsifier sodium dodecylbenzenesulfonate (SDBS), 0.08g of emulsifier CO897, 0.3g of buffer sodium bicarbonate, 0.05g of potassium persulfate (KPS) and 99.05g of distilled water were placed in a beaker and ultrasonically dispersed for 30min to form a pre-emulsion solution A; 0.05g of KPS, 0.01g of N,N'-methylenebisacrylamide (MBA), 7g of monomer styrene (St), 1.5g of monomer acrylic acid (AA) and 1.5g of monomer methyl methacrylate (MMA) were fully dissolved by magnetic stirring for 7h to obtain a pre-emulsion solution B;

[0090] (2) The pre-emulsified solution A and pre-emulsified solution B obtained in step (1) were directly and uniformly mixed and placed into a four-necked flask and emulsion polymerization was carried out for 6 hours without nitrogen gas. After the emulsification reaction was completed, the obtained magnetic polystyrene microsphere emulsion was cooled to room temperature. Then, the magnetic polystyrene microsphere emulsion was poured into a 0.5 mol / L hydrochloric acid solution and washed for 24 hours to remove uncoated magnetic nanoparticles. The emulsion was then centrifuged three times with anhydrous ethanol and distilled water. The centrifugation speed was adjusted to 14000 rad / min. In the end, pure magnetic polystyrene microspheres were not obtained, only a milky white liquid.

[0091] Performance testing:

[0092] (1) Morphological observation: The magnetic polystyrene microspheres obtained in Example 1 were observed using a HITACHI S-4800 scanning electron microscope. The 20K scanning electron microscope image of the magnetic polystyrene microspheres obtained in Example 1 is shown below. Figure 1 The scanning electron microscope image of the magnetic polystyrene microspheres obtained in Example 1 at 40K is shown below. Figure 2 As shown, from Figure 1 and Figure 2 It is clearly visible that the iron oxide nanoparticles are encapsulated on the polystyrene microspheres.

[0093] (2) Dispersibility test: The monodispersity and particle size of the magnetic polystyrene microspheres obtained in Example 1 were characterized using a Malvern Zetasizer 3000 dynamic light scattering particle size analyzer (DLS). Figure 2The prepared magnetic polystyrene microspheres exhibit excellent monodispersity.

[0094] The magnetic polystyrene microspheres obtained in Examples 1-5 and Comparative Example 1 were tested according to the above test results. The test results are shown in Table 1.

[0095] Table 1

[0096] Monodispersity (PDI) Particle size / nm Example 1 0.005 210 Example 2 0.017 260 Example 3 0.024 320 Example 4 0.006 238 Example 5 0.006 211 Comparative Example 1 / /

[0097] According to the data in Table 1, the monodispersity of the magnetic polystyrene microspheres provided by this invention is 0.005-0.024, and the particle size is 210-320 nm. However, the method in Comparative Example 1 (conventional emulsion polymerization under nitrogen-free conditions) failed to synthesize the magnetic polystyrene nanospheres and was not successfully synthesized.

[0098] The applicant declares that this invention illustrates a magnetic polystyrene microsphere, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A magnetic polystyrene microsphere, characterized in that, Its preparation method includes the following steps: (1) Place 0.5 g of oleic acid modified iron oxide magnetic nanoparticles with an average particle size of 5 nm, 0.02 g of emulsifier sodium dodecylbenzenesulfonate, 0.08 g of emulsifier CO897, 0.3 g of sodium bicarbonate, 0.05 g of potassium persulfate and 99.05 g of distilled water into a beaker and ultrasonically disperse for 30 min to form a pre-emulsion solution A. Then inject the pre-emulsion solution A into a 100 mL syringe and remove the air from the syringe A for later use. Dissolve 0.05 g of KPS, 0.01 g of N,N'-methylenebisacrylamide, 7 g of styrene monomer, 1.5 g of acrylic acid monomer and 1.5 g of methyl methacrylate monomer by magnetic stirring for 7 h to obtain a pre-emulsion solution B. Inject the pre-emulsion solution B into a 10 mL syringe B and remove the air from the syringe for later use. (2) Fix syringe A containing pre-emulsified solution A and syringe B containing pre-emulsified solution B obtained in step (1) onto a microfluidic pump. Then, connect the two syringes to the two inlets of a Y-shaped serpentine channel microfluidic chip with a size of 6×4×2.5 cm, an inner channel size of 0.3 mm, and an outer channel size of 0.5 mm, respectively, through a polytetrafluoroethylene tube with an inner diameter of 0.5 mm and an outer diameter of 0.8 mm. Then, connect the outlet end of the Y-shaped chip with a polytetrafluoroethylene tube of the same inner diameter. Finally, place the microfluidic chip in an oil bath at 70°C, and adjust the flow rate of pre-emulsified solution A to 10 mL / h and the flow rate of pre-emulsified solution B to 1 mL / h, so that the two pre-emulsified solutions are fully and uniformly mixed in the Y-shaped serpentine channel chip and undergo emulsion polymerization reaction for 2 min. After the emulsification reaction is completed, cool the obtained magnetic polystyrene microsphere emulsion to room temperature, and then pour the magnetic polystyrene microsphere emulsion into a 0.5% concentration. The uncoated magnetic nanoparticles were washed in mol / L hydrochloric acid solution for 24 h to remove them. Then, they were washed three times by centrifugation with anhydrous ethanol and distilled water, respectively, with the centrifugation speed adjusted to 14000 rad / min. Finally, magnetic polystyrene microspheres with an average particle size of 210 nm were obtained.

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