Preparation method of Janus mesoporous microspheres

Abstract

The application relates to a preparation method of Janus mesoporous microspheres and belongs to the technical field of materials. The method comprises the following steps: step 1, mixing a silicon precursor and a second component precursor as an organic phase of microfluidics; step 2, dissolving a surfactant in water as an aqueous phase of microfluidics; step 3, forming a microsphere emulsion in a microfluidic system; step 4, passing through a curved pipeline to perform first heating treatment, so that the second component generates eccentric growth under the action of centrifugal force; step 5, collecting and then performing second heating treatment to make the silicon precursor generate mesoporous microsphere growth reaction; and step 6, obtaining Janus mesoporous microspheres through post-treatment. The Janus mesoporous microspheres prepared by the application are variable in component, controllable in structure and adjustable in size, can be applied to catalyze hydrogen peroxide decomposition to form microbubbles, can be used as micro-motors for directional migration under physiological or pathological conditions, and can be applied to the fields of disease diagnosis and treatment.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a method for preparing Janus mesoporous microspheres. Background Technology

[0002] Microsphere materials have been widely studied and applied in fields such as coatings, cosmetics, sensing, and biomedicine. Controlling the morphology and structure of microspheres has always been an important topic in materials science. Among them, anisotropic (Janus) microspheres and porous microspheres, due to their unique structures and integrated multiple properties, have become one of the research hotspots in materials science over the past two decades.

[0003] Janus materials are a special class of multiphase, multi-component functional composite materials with different chemical compositions and functional spatial partitioning characteristics. Janus mesoporous microspheres can efficiently stabilize interfaces and have well-defined orientation characteristics. The gaps between particles can provide channels for the transport of matter between two phases. With multiple properties and special microstructures, they have broad application prospects in fields such as microelectromechanical systems, bio-orientation, fluid mechanics, and disease diagnosis and treatment.

[0004] Currently, the main methods for preparing Janus nanoparticles include physical vapor deposition, electrochemical deposition, microfluidics, and self-assembly methods (such as Pickering emulsion method, transient nanoprecipitation method, and selective growth). However, existing methods generally suffer from high costs, complex processes, or the need for specialized equipment, making it difficult to achieve controllable synthesis and mass production. Furthermore, current self-driven research often uses spherical micro / nanoparticles, primarily due to their simple preparation and clear physical models; however, spherical particles cannot meet the demands for anisotropic structures and multifunctional integration.

[0005] Therefore, there is an urgent need to develop a method for preparing Janus mesoporous microspheres that can precisely control the anisotropic structure and mesoporous properties of microspheres, is easy to operate, low in cost, and suitable for large-scale production. Summary of the Invention

[0006] To address the technical problems of high cost, complex process, and difficulty in controllable synthesis and mass production of Janus microspheres in existing technologies, this invention provides a method for preparing Janus mesoporous microspheres. The aim is to achieve the controllable preparation of Janus mesoporous microspheres with variable composition, controllable structure, and adjustable size by coupling microfluidic technology with the centrifugal force field of curved flow channels.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing Janus mesoporous microspheres includes the following steps: Step 1: Mix the silicon precursor with the second component precursor to form the organic phase for microfluidic control; Step 2: Dissolve the surfactant in water to form the aqueous phase of the microfluidic system; Step 3: In the microfluidic system, the organic phase and the aqueous phase are brought into contact in the flow channel to form a microsphere emulsion; Step 4: Pass the obtained microsphere emulsion into a curved pipe for the first heating treatment, so that the second component will grow eccentrically under the action of centrifugal force; Step 5: Collect the microsphere emulsion after step 4 and perform a second heating treatment to induce the growth of mesoporous microspheres in the silicon precursor. Step 6: After the reaction is completed, post-processing is performed to obtain the Janus mesoporous microspheres.

[0008] The silicon precursor mentioned in step 1 is selected from one or any combination of tetraethyl orthosilicate (TEOS), bis(diethylamino)silane (BDEAS), bis(tert-butylamino)silane (BTBAS), and octamethylcyclotetrasiloxane (OMCTS). Preferably, the silicon precursor is tetraethyl orthosilicate.

[0009] In step 1, the second component is selected from gold (Au), platinum (Pt), silver (Ag), palladium (Pd), selenium (Se), or oxides. The precursor of the second component is selected from chloroauric acid, chloroplatinic acid, chloroplatinate, selenite, or metal ions. Preferably, the precursor of the second component is chloroplatinic acid.

[0010] The surfactant mentioned in step 2 is selected from one or any combination of vitamin E polyethylene glycol succinate (VE-TPGS), sorbitan fatty acid ester (Span), polyoxyethylene-polyoxypropylene polymer (Pluronic), and hexadecyltrimethylammonium chloride (CTAB). Preferably, the surfactant is polyoxyethylene-polyoxypropylene polymer (Pluronic).

[0011] The content of the second component precursor in the organic phase in step 1 is 0.1 wt% to 99.9 wt%; the content of the surfactant in the aqueous phase in step 2 is 0.01 wt% to 5 wt%.

[0012] The length of the bent pipe in step 4 is 1 cm to 100 cm, the radius of curvature of the bent pipe is 0.5 cm to 50 cm, and the temperature of the first heat treatment is 30°C to 100°C.

[0013] In step 5, the temperature of the second heating treatment is 30°C to 100°C, and the time is 0.5 h to 5 h.

[0014] The Janus mesoporous microspheres have a particle size of 1 μm to 1000 μm.

[0015] The beneficial effects of this invention are: 1. This invention involves adding a second component precursor to a silicon precursor, forming a microsphere emulsion with uniform size using microfluidic technology, and then using the centrifugal force field in a curved channel to cause the second component to grow eccentrically, thereby obtaining Janus mesoporous microspheres with a well-defined composition, controllable structure, and narrow particle size distribution. 2. The present invention can achieve precise control over the component ratio, eccentric structure and particle size of Janus mesoporous microspheres by adjusting the content of the second component precursor in the organic phase in step 1, the geometric parameters (length and radius of curvature) of the curved pipe in step 4, and the heating temperature and other process conditions. 3. The Janus mesoporous microspheres prepared by this invention can form microbubbles during the process of catalytic decomposition of hydrogen peroxide to produce oxygen. Under physiological or pathological conditions, they can act as micromotors to migrate directionally under a concentration gradient, thereby realizing the diagnostic and therapeutic functions of diseases and playing an important role in promoting the biopharmaceutical industry. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the process for preparing Janus mesoporous microspheres according to the present invention; Figure 2 This is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-1 obtained in Example 1 of the present invention; Figure 3 This is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-2 obtained in Example 2 of the present invention; Figure 4 This is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-3 obtained in Example 3 of the present invention. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0019] Example 1 This embodiment provides a method for preparing Janus mesoporous microspheres (Janus-Pt@SiO2-1), specifically including the following steps: Step 1: Take 100 g of tetraethyl orthosilicate (TEOS) and mix it with 5 g of chloroplatinic acid. Stir well to form the organic phase for microfluidics. The content of chloroplatinic acid in the organic phase is 5 wt%.

[0020] Step 2: Take 100 mL of pure water, add 5 g of surfactant Pluronic, and stir until completely dissolved to form the aqueous phase for microfluidics; the content of surfactant Pluronic in the aqueous phase is 5 wt%.

[0021] Step 3: Inject the aqueous phase and organic phase into the microfluidic system, the flow channel of which has a diameter of 10 μm; the organic phase and the aqueous phase contact in the flow channel and form a uniformly sized microsphere emulsion under the shearing action of the continuous phase.

[0022] Step 4: The obtained microsphere emulsion is passed into a curved pipe for the first heating treatment; the curved pipe has a radius of curvature of 5 cm, a length of 50 cm, and a heating temperature of 65°C; during the movement in the curved channel, the microspheres are subjected to centrifugal force, and the second component (platinum) precursor in them undergoes eccentric migration.

[0023] Step 5: Collect the microsphere emulsion after step 4 and place it under 85°C for a second heating treatment for 2 hours to allow the silicon precursor to fully undergo the mesoporous microsphere growth reaction.

[0024] Step 6: After the reaction is complete, the product is centrifuged, washed with deionized water, and dried to obtain Janus mesoporous microspheres (Janus-Pt@SiO2-1).

[0025] The Janus-Pt@SiO2-1 prepared in this embodiment was characterized, and its microsphere particle size was 173±4 nm, with a platinum content of 2.7 wt%. See also Figure 2 The image shown is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-1 obtained in this embodiment. Figure 2 It can be clearly observed that the microspheres exhibit a regular spherical morphology and a distinct Janus structure. The platinum component (the dark area in the figure) is eccentrically distributed in the microspheres, indicating that the method of the present invention has successfully prepared Janus mesoporous microspheres with anisotropic structure.

[0026] Example 2 This embodiment provides a method for preparing Janus mesoporous microspheres (Janus-Pt@SiO2-2), specifically including the following steps: Step 1: Take 100 g of tetraethyl orthosilicate (TEOS) and mix it with 4 g of chloroplatinic acid. Stir well to form the organic phase of the microfluidic system. The content of chloroplatinic acid in the organic phase is 4 wt%.

[0027] Step 2: Take 100 mL of pure water, add 5 g of surfactant Pluronic, and stir until completely dissolved to form the aqueous phase for microfluidics; the content of surfactant Pluronic in the aqueous phase is 5 wt%.

[0028] Step 3: Inject the aqueous phase and organic phase into the microfluidic system, the flow channel of which has a diameter of 20 μm; the organic phase and the aqueous phase contact in the flow channel and form a uniformly sized microsphere emulsion under the shearing action of the continuous phase.

[0029] Step 4: The obtained microsphere emulsion is passed into a curved pipe for the first heating treatment; the curved pipe has a radius of curvature of 5 cm, a length of 50 cm, and a heating temperature of 65°C; during the movement in the curved channel, the microspheres are subjected to centrifugal force, and the second component (platinum) precursor in them undergoes eccentric migration.

[0030] Step 5: Collect the microsphere emulsion after step 4 and place it under 85°C for a second heating treatment for 2 hours to allow the silicon precursor to fully undergo the mesoporous microsphere growth reaction.

[0031] Step 6: After the reaction is complete, the product is centrifuged, washed with deionized water, and dried to obtain Janus mesoporous microspheres (Janus-Pt@SiO2-2).

[0032] The Janus-Pt@SiO2-2 prepared in this embodiment was characterized, and its microsphere particle size was 185±6 nm, with a platinum content of 2.4 wt%. See also Figure 3 The image shown is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-2 obtained in this embodiment. Figure 3 It can be clearly observed that the microspheres exhibit a regular spherical morphology and a distinct Janus structure. The platinum component (the dark area in the figure) is eccentrically distributed in the microspheres, indicating that the method of the present invention has successfully prepared Janus mesoporous microspheres with anisotropic structure.

[0033] Example 3 This embodiment provides a method for preparing Janus mesoporous microspheres (Janus-Pt@SiO2-3), specifically including the following steps: Step 1: Take 100 g of tetraethyl orthosilicate (TEOS) and mix with 6 g of chloroplatinic acid, stir evenly, and use it as the organic phase of microfluidics; the content of chloroplatinic acid in the organic phase is 6 wt%.

[0034] Step 2: Take 100 mL of pure water, add 5 g of surfactant Pluronic, and stir until completely dissolved to form the aqueous phase for microfluidics; the content of surfactant Pluronic in the aqueous phase is 5 wt%.

[0035] Step 3: Inject the aqueous phase and organic phase into the microfluidic system, the flow channel of which has a diameter of 20 μm; the organic phase and the aqueous phase contact in the flow channel and form a uniformly sized microsphere emulsion under the shearing action of the continuous phase.

[0036] Step 4: The obtained microsphere emulsion is passed into a curved pipe for the first heating treatment; the curved pipe has a radius of curvature of 5 cm, a length of 50 cm, and a heating temperature of 65°C; during the movement in the curved channel, the microspheres are subjected to centrifugal force, and the second component (platinum) precursor in them undergoes eccentric migration.

[0037] Step 5: Collect the microsphere emulsion after step 4 and place it under 85°C for a second heating treatment for 2 hours to allow the silicon precursor to fully undergo the mesoporous microsphere growth reaction.

[0038] Step 6: After the reaction is complete, the product is centrifuged, washed with deionized water, and dried to obtain Janus mesoporous microspheres (Janus-Pt@SiO2-3).

[0039] The Janus-Pt@SiO2-3 prepared in this embodiment was characterized, and its microsphere particle size was 191±7 nm, with a platinum content of 2.9 wt%. See also Figure 4 The image shown is a transmission electron microscope (TEM) image of Janus-Pt@SiO2-3 obtained in this embodiment. Figure 4 It can be clearly observed that the microspheres exhibit a regular spherical morphology and a distinct Janus structure. The platinum component (the dark area in the figure) is eccentrically distributed in the microspheres, indicating that the method of the present invention has successfully prepared Janus mesoporous microspheres with anisotropic structure.

[0040] Performance Characterization The particle size and platinum content of the Janus mesoporous microspheres prepared in Examples 1-3 were characterized, and the results are shown in Table 1.

[0041] Table 1 Performance parameters of Janus mesoporous microspheres prepared in Examples 1-3 See Figures 2 to 4The images show transmission electron microscope (TEM) images of Janus-Pt@SiO2-1, Janus-Pt@SiO2-2, and Janus-Pt@SiO2-3 prepared in Examples 1-3, respectively. As can be clearly seen from the images, all samples exhibit a regular spherical morphology and a distinct Janus structure. The platinum component (the darker area in the image) is eccentrically distributed within the microspheres, confirming that the method of this invention successfully prepared Janus mesoporous microspheres with anisotropic structures.

[0042] Furthermore, as shown in Table 1, by adjusting the amount of chloroplatinic acid added to the organic phase in step 1 (5 wt%, 4 wt%, and 6 wt% in Examples 1-3, respectively), the platinum content in the final Janus mesoporous microspheres can be controlled (2.7 wt%, 2.4 wt%, and 2.9 wt%, respectively). Simultaneously, by adjusting the channel diameter of the microfluidic system in step 3 (10 μm in Example 1, and 20 μm in Examples 2 and 3), the particle size of the microspheres can be controlled to a certain extent. These results demonstrate that the method of the present invention has good controllability in both composition and size.

[0043] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing Janus mesoporous microspheres, characterized in that, Includes the following steps: Step 1: Mix the silicon precursor with the second component precursor to form the organic phase for microfluidic control; Step 2: Dissolve the surfactant in water to form the aqueous phase of the microfluidic system; Step 3: In the microfluidic system, the organic phase and the aqueous phase are brought into contact in the flow channel to form a microsphere emulsion; Step 4: Pass the obtained microsphere emulsion into a curved pipe for the first heating treatment, so that the second component will grow eccentrically under the action of centrifugal force; Step 5: Collect the microsphere emulsion after step 4 and perform a second heating treatment to induce the growth of mesoporous microspheres in the silicon precursor. Step 6: After the reaction is completed, post-processing is performed to obtain the Janus mesoporous microspheres.

2. The preparation method according to claim 1, characterized in that, The silicon precursor mentioned in step 1 is selected from one or any combination of tetraethyl orthosilicate, bis(diethylamino)silane, bis(tert-butylamino)silane, and octamethylcyclotetrasiloxane.

3. The preparation method according to claim 1, characterized in that, In step 1, the second component is selected from gold, platinum, silver, palladium, selenium, or oxides; the precursor of the second component is selected from chloroauric acid, chloroplatinic acid, chloroplatinate, selenite, or metal ions.

4. The preparation method according to claim 1, characterized in that, The surfactant mentioned in step 2 is selected from one or any combination of vitamin E polyethylene glycol succinate, sorbitan fatty acid ester, polyoxyethylene-polyoxypropylene polymer, and hexadecyltrimethylammonium chloride.

5. The preparation method according to claim 1, characterized in that, The content of the second component precursor in the organic phase in step 1 is 0.1 wt% to 99.9 wt%; the content of the surfactant in the aqueous phase in step 2 is 0.01 wt% to 5 wt%.

6. The preparation method according to claim 1, characterized in that, The length of the bent pipe in step 4 is 1 cm to 100 cm, the radius of curvature of the bent pipe is 0.5 cm to 50 cm, and the temperature of the first heat treatment is 30°C to 100°C.

7. The preparation method according to claim 1, characterized in that, In step 5, the temperature of the second heating treatment is 30°C to 100°C, and the time is 0.5 h to 5 h.

8. The preparation method according to claim 1, characterized in that, The Janus mesoporous microspheres have a particle size of 1 μm to 1000 μm.

9. The preparation method according to claim 1, characterized in that, In step 1, the silicon precursor is tetraethyl orthosilicate, and the second component precursor is chloroplatinic acid, with the content of chloroplatinic acid in the organic phase being 5 wt%; in step 2, the surfactant is a polyoxyethylene-polyoxypropylene polymer, with the content of polyoxyethylene-polyoxypropylene polymer in the aqueous phase being 1 wt%; in step 4, the radius of curvature of the curved pipe is 5 cm, the length is 50 cm, and the temperature of the first heat treatment is 65°C; in step 5, the temperature of the second heat treatment is 85°C, and the time is 2 h.

10. Janus mesoporous microspheres prepared by the method according to any one of claims 1 to 9, characterized in that, The Janus mesoporous microspheres are mesoporous silica microspheres, and the second component is eccentrically distributed in the microspheres.

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