Ordered multilayer perforated mesoporous microsphere as well as preparation method and application thereof

Abstract

The invention discloses an ordered multilayer perforated mesoporous microsphere as well as a preparation method and application thereof. The ordered multilayer perforated mesoporous microsphere has a regular spherical geometric shape; a skeleton structure in the microsphere is in an onion-shaped concentric circle layered nested configuration and is composed of a plurality of independent layered structures which are wrapped in sequence; the interior of each independent layered structure comprises columnar through hole arrays which are arranged in a highly ordered manner and are symmetrically distributed in a hexagonal manner, and the columnar through holes form regular and periodic hexagonal honeycomb pore networks in the layered structures where the columnar through holes are located; the columnar through holes penetrate through the layered structures where the columnar through holes are located, and in a three-dimensional space, the columnar through holes between different layered structures and the columnar through holes in the same layered structure are communicated with one another, so that a three-dimensional communicated pore network penetrating through the interior of the whole microsphere is formed. The ordered multilayer perforated mesoporous microsphere is novel in structure and can be applied to the fields of precious metal recovery, precious metal ion targeted adsorption, energy storage and conversion devices and drug delivery.

Description

Technical Field

[0001] This invention belongs to the field of mesoporous materials technology, specifically relating to an ordered multilayer perforated mesoporous microsphere, its preparation method, and its application. Background Technology

[0002] Mesoporous microspheres are materials with excellent pore structure and high specific surface area, commonly used in applications such as adsorption and catalysis. However, to improve their application performance and expand their functions, researchers have begun to focus on how to achieve ordered bicontinuous structures and introduce them into mesoporous microspheres. The ordered periodic structure and three-dimensional interconnected network and pore channels of bicontinuous structures facilitate molecular diffusion into the material interior for sufficient mass transfer and reaction, thereby significantly improving mass transport efficiency. Their unique structural advantages and physical properties enable ordered bicontinuous mesoporous microspheres to exhibit excellent performance in energy storage and conversion, metamaterials, photonic crystals, drug control and release, nanoreactors, and biomolecule selection. Therefore, how to prepare bicontinuous mesoporous microspheres has become a major research hotspot in the field of mesoporous materials in recent years.

[0003] Self-assembly of amphiphilic block copolymers is a fundamental approach to preparing mesoporous microspheres. The hydrophobic effect during assembly is the key reason for the generation of polymer microspheres with different morphologies and structures. By selecting appropriate templates or surfactants and adjusting the packing parameter (ρ) of the block copolymer to make ρ greater than 1, it is beneficial to form an inverted structure. Currently, common ordered bicontinuous mesoporous microspheres include two morphologies: Cubosome cubic and Hexosome hexagonal. The bulk structure of Cubosome mesoporous microspheres includes three types: Im3m, Pn3m, and Ia3d, while the bulk structure of Hexosome hexagonal microspheres is P6mm. For example, Mai et al. utilized the block copolymer poly(ethylene oxide-b-polystyrene) (PEO) 45 -b-PS n ), where the volume fraction of PEO (f PEO The polystyrene (PS) content ranged from 5.1% to 9.7%, and ordered bicontinuous mesoporous microspheres of different morphologies were prepared by solvent exchange precipitation. With increasing water content, the morphology of the polymer microspheres changed from vesicles to large complex vesicles (LCVs) and bicontinuous mesoporous microspheres. As the degree of PS polymerization (n) increased (i.e., f decreased), the morphology of the polymer microspheres changed from vesicles to large complex vesicles (LCVs) and then to bicontinuous mesoporous microspheres. PEO Three different bicontinuous mesoporous microspheres with varying structures were observed: Im3m cubic, Pn3m cubic, and P6mm hexagonal. Notably, these bicontinuous mesoporous microspheres only appeared in f... PEOWithin a narrow window range of 5.1% to 7.9%. Additionally, Wu et al. used polymerization-induced self-assembly (PISA) to prepare Cubosome-type bicontinuous mesoporous microspheres composed of PDMA-bP (St-alt-PFS) through RAFT polymerization of poly(N,N-dimethylacrylamide) (PDMA), styrene (St), and pentafluorostyrene (PFS).

[0004] The commonly seen Cubosome-type cubes and Hexosome-type hexagons all contain corresponding bulk bicontinuous structures. However, in the field of bicontinuous structures, there exists another type of bulk-ordered bicontinuous structure: the perforated layer structure. While novel in structure, related reports are relatively rare. In two-dimensional polymer films, researchers have prepared bicontinuous films with perforated layered structures based on the bulk self-assembly of block copolymers. However, due to the narrow "phase" window, the assembly conditions and control parameters are highly demanding, requiring very precise adjustments. This makes it difficult to obtain perforated layered structures using traditional assembly methods, especially for three-dimensional mesoporous microspheres. Therefore, experimental studies on such perforated layered mesoporous microspheres have not yet been reported. Based on this, how to prepare mesoporous microspheres with perforated layered structures presents both new opportunities and challenges for the field of mesoporous materials science. The introduction of perforated layered structures not only improves the stability of polymer microspheres but also enhances the utilization rate of active sites and mass transport efficiency, resulting in higher functionalizability. This expands the application fields of mesoporous microspheres and provides more possibilities for material design, demonstrating broad application value in areas such as precious metal recycling and environmental remediation, energy conversion, and biomedicine. Therefore, there is an urgent need to develop a mesoporous microsphere with a perforated layered structure and its preparation method. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide an ordered multilayer perforated mesoporous microsphere, its preparation method and application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides an ordered multilayer perforated mesoporous microsphere, wherein the microsphere has a regular spherical geometric shape;

[0007] The internal skeletal structure of the microspheres presents an onion-like concentric layered nested configuration, consisting of multiple independent, sequentially wrapped layered structures;

[0008] Each of the independent layered structures contains a highly ordered array of columnar through-holes distributed in a hexagonal phase P6mm symmetry. The columnar through-holes form a regular and periodic hexagonal honeycomb-like channel network within their respective layered structures.

[0009] The columnar through-holes penetrate the layered structure in which they are located, and in three-dimensional space, the columnar through-holes between different layered structures and the columnar through-holes within the same layered structure are interconnected to form a three-dimensional interconnected pore network that runs through the entire interior of the microsphere.

[0010] Furthermore, the ordered multilayer perforated mesoporous microspheres have a particle size of 0.02–10 μm, the columnar pores all have the same pore size of 2–100 nm, the layered structure has a thickness of 5–100 nm, and the columnar pores have a period of 5–100 nm.

[0011] Furthermore, the particle size of the ordered multilayer perforated mesoporous microspheres is 0.05–1 μm.

[0012] Furthermore, the diameter of the columnar through-hole is 5–50 nm.

[0013] Furthermore, the number of layers in the ordered multilayer perforated mesoporous microsphere layered structure is adjustable, ranging from 1 to 20 layers; the number of columnar through-holes in the ordered multilayer perforated mesoporous microsphere is adjustable, ranging from 1 to 2000.

[0014] Furthermore, when the ordered multilayer perforated mesoporous microsphere layered structure has 1 layer, the number of columnar through-holes in the ordered multilayer perforated mesoporous microsphere is 1 to 9, and the number of columnar through-holes in the ordered multilayer perforated mesoporous microsphere increases with the increase of the microsphere size.

[0015] Furthermore, the framework surface of the ordered multilayer perforated mesoporous microspheres is loaded with active groups, and the framework surface of the ordered multilayer perforated mesoporous microspheres includes the outer surface of the ordered multilayer perforated mesoporous microspheres, the interlayer interface, and the inner surface of all columnar through-holes.

[0016] Preferably, the active group is a pyridine group.

[0017] The active groups can interact with metal ions, metal nanoparticles or inorganic oxides, as well as with precursors of metal nanoparticles or inorganic oxides.

[0018] On the other hand, the present invention provides a method for preparing any of the above-described ordered multilayer perforated mesoporous microspheres, comprising the following steps:

[0019] (1) Dissolve the diblock copolymer in an organic solvent that is insoluble in water to obtain a diblock copolymer solution, and dissolve the small alkane molecules that are insoluble in water in an organic solvent that is insoluble in water to obtain a small alkane molecule solution; mix the diblock copolymer solution and the small alkane molecule solution and stir for a period of time to obtain a comb-like supramolecular block copolymer solution based on hydrogen bonds.

[0020] (2) The comb-shaped supramolecular block copolymer solution prepared in step (1) is mixed with a haloalkane crosslinking agent and crosslinked after stirring for a period of time to obtain a composite supramolecular block copolymer solution.

[0021] (3) Using the emulsion-solvent evaporation method, a spherical polymer microsphere solution with an internal layered structure is prepared using the composite supramolecular block copolymer solution obtained in step (2);

[0022] (4) The spherical polymer microsphere solution prepared in step (3) is mixed with ethanol, and the ordered multilayer perforated mesoporous microspheres are obtained after centrifugation and purification.

[0023] Further, the diblock copolymer in step (1) includes a polymer constituting the dispersed phase and a polymer constituting the continuous phase; the polymer constituting the dispersed phase is poly(styrene), poly(isoprene), poly(acrylate), or poly(butadiene), and the polymer constituting the continuous phase is poly(2-vinylpyridine) or poly(4-vinylpyridine); the molecular weight of the hydrophobic segment constituting the dispersed phase in the diblock copolymer is 5,000 to 100,000, and the molecular weight of the hydrophilic segment constituting the continuous phase in the diblock copolymer is 5,000 to 100,000; the ratio of the molecular weight of the hydrophobic polymer constituting the dispersed phase to the molecular weight of the hydrophilic polymer constituting the continuous phase in the diblock copolymer is 2.8 to 3.2.

[0024] It should be noted that the purpose of using a molecular weight ratio of 2.8 to 3.2 for hydrophobic segments to hydrophilic segments is to increase the effective volume fraction of the hydrophobic segments, thereby changing the packing parameters of the block copolymer. This is beneficial for adjusting the packing parameters to a value greater than 1, which is conducive to the formation of a bicontinuous structure with multilayer perforation.

[0025] Preferably, the diblock copolymer is poly(styrene)-b-poly(4-vinylpyridine) (PS-b-P4VP). For example, the diblock copolymer can be: PS 51k -b-P4VP 18k PS 61k -b-P4VP 21k PS 30k -b-P4VP 10k PS 45 -b-P4VP 15k wait.

[0026] Further, the organic solvent mentioned in step (1) is at least one of toluene, dichloromethane, and chloroform.

[0027] Furthermore, the alkane molecule mentioned in step (1) is 3-pentadecanylphenol.

[0028] Further, in step (1), the molar ratio of the diblock copolymer to the alkane small molecule is 1:(1.1~1.3), and the molar amount of the diblock copolymer is the molar amount of the pyridine group.

[0029] Alkane small molecules can form hydrogen bonds with the pyridine groups of diblock copolymers, forming comb-like supramolecular block copolymers. This alters the volume fraction of hydrophilic segments in the diblock copolymer, thus controlling the microphase separation structure and assembly morphology. When using the emulsion-solvent evaporation method for the three-dimensional confined assembly of block copolymers, the morphology of the resulting polymer microspheres changes with the amount of alkane small molecules added, until the hydrogen bonds formed between the pyridine groups and the alkane small molecules reach saturation. When the amount of alkane small molecules added is small, onion-like layered microspheres without perforation are produced. When the amount of alkane small molecules added is large, mesoporous microspheres with a hexosome-type inverted columnar structure are produced.

[0030] Furthermore, the stirring temperature in step (1) is 10–35°C, and the stirring time is 12–48 h.

[0031] Further, the concentration of the diblock copolymer solution in step (1) is 1 to 20.0 mg / mL, and the concentration of the alkane small molecule solution in step (1) is 1 to 20.0 mg / mL.

[0032] Further, the haloalkane mentioned in step (2) is a dihaloalkane containing a halogen element at each end of the carbon chain; preferably, the halogen element contained in the haloalkane is at least one of bromine and iodine; preferably, the haloalkane is 1,2-diiodomethane, 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane or 1,8-dibromooctane.

[0033] Further, the molar ratio of the diblock copolymer in step (1) to the haloalkane in step (2) is 1:(0.3-0.8), and the molar amount of the diblock copolymer is the molar amount of the pyridine group.

[0034] The amount of dihaloalkane crosslinking agent added should not be too high or too low. If the amount is too low, onion-like layered microspheres with no pore structure will form, preventing the formation of multilayered perforated mesoporous microspheres. If the amount is too high, the diblock copolymer becomes too hydrophilic, causing the pyridine groups to be highly protonated, thus altering the phase separation structure of the polymer microspheres and preventing the formation of ordered multilayered perforated mesoporous microspheres.

[0035] It should be noted that the crosslinking of diblock copolymers with dihaloalkanes is a unique advantage of the emulsion-solvent evaporation method used in this invention. The dihaloalkanes serve three purposes: First, they act as crosslinking agents, effectively crosslinking the hydrophilic segments of the diblock copolymer, reducing its effective cross-sectional area, and thus altering the packing parameters of the copolymer. This facilitates the adjustment of the packing parameters to a range greater than 1, forming a multilayered, perforated, bicontinuous structure. Second, they regulate interfacial interactions. The halogens in the dihaloalkanes can undergo quaternization with pyridine groups, enhancing the hydrophilicity of the diblock copolymer and altering the oil-water interface interaction at the emulsion droplet surface. Because the antiphase bicontinuous structure has a narrow "phase" window, the requirements for assembly conditions and control parameters are extremely stringent. The introduction of dihaloalkanes can effectively and more precisely adjust the volume fraction of the block copolymer and interfacial interactions, thus facilitating the acquisition of a perforated layered structure. Third, they enhance the solvent resistance and stability of the mesoporous microspheres, ensuring that the microspheres retain their structural integrity after ethanol impregnation without disassembly, which is beneficial for further functionalization.

[0036] Furthermore, the stirring temperature in step (2) is 10–35°C, and the stirring time is 4–48 h.

[0037] Further, step (3) specifically involves mixing the composite supramolecular block copolymer solution prepared in step (2) with an aqueous solution of a surfactant, then emulsifying it to obtain an emulsion. The emulsion is then placed in an open environment at 20–35°C for evaporation. Once the organic solvent has completely evaporated, a spherical polymer microsphere solution with an internal layered structure can be obtained.

[0038] Furthermore, the surfactant is polyvinyl alcohol;

[0039] Further, the concentration of the aqueous solution of the surfactant is 1.0 to 10.0 mg / mL, and the volume ratio of the composite supramolecular block copolymer solution to the aqueous solution of the surfactant is 1:(5 to 15).

[0040] Furthermore, the device used for emulsification is a membrane emulsification device, the membrane pore size used for emulsification is 0.45μm, 0.20μm or 1.0μm, and the number of membrane passes for emulsification is 2 to 50.

[0041] Further, the volume ratio of ethanol and spherical polymer microsphere solution in step (4) is (1.6-3):1.

[0042] The purpose of washing the spherical polymer microspheres with an internal layered structure with ethanol is to dissolve the water-insoluble alkane molecules present in the microspheres, which helps to release more space inside the microspheres and thus form a three-dimensional interconnected porous structure.

[0043] On the other hand, the present invention provides an application of ordered multilayer perforated mesoporous microspheres as described above or ordered multilayer perforated mesoporous microspheres prepared by any of the above preparation methods in noble metal recovery, targeted adsorption of noble metal ions, energy storage and conversion devices, and drug delivery.

[0044] Precious metal recovery: Ordered multilayer perforated mesoporous microspheres are used as selective adsorbents to separate and recover precious metal elements from solutions or waste liquids.

[0045] Targeted adsorption of noble metal ions: Ordered multilayer perforated mesoporous microspheres achieve highly selective adsorption of specific noble metal ions based on the coordination of surface-active groups.

[0046] Energy storage and conversion devices: Ordered multilayer perforated mesoporous microspheres are used as electrode materials, catalyst supports or ion conduction media.

[0047] Drug delivery: Ordered multilayer perforated mesoporous microspheres serve as carriers for controllable loading and release of active substances.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] (1) The mesoporous microspheres provided by this invention have a novel structure with an ordered multilayered perforated structure. The microsphere skeleton has an onion-like layered structure, and each layer contains a highly ordered array of columnar through-holes distributed with hexagonal phase P6mm symmetry. The columnar through-holes form a regular and periodic hexagonal honeycomb-like pore network within their respective layered structures, and the pores of the columnar through-holes are three-dimensionally interconnected. This three-dimensionally interconnected multilayered perforated structure improves the utilization rate of active sites and the efficiency of material diffusion and transport. Existing experimental studies only focus on two-dimensional thin films with perforated layered structures, but no experimental studies on three-dimensional mesoporous microspheres with perforated layered structures have been reported. Therefore, this invention provides a reference experimental research demonstration for the preparation of three-dimensional perforated layered mesoporous microspheres.

[0050] (2) The method for preparing mesoporous microspheres provided by this invention is simple, mild, and easy to control. To prepare ordered multilayer perforated mesoporous microspheres, this invention first prepares comb-shaped supramolecular block copolymers and crosslinks the hydrophilic segments with dihaloalkanes. Then, polymer microspheres are obtained using an emulsion-solvent evaporation method, followed by washing with ethanol to obtain ordered multilayer perforated mesoporous microspheres. Specifically, this invention uses supramolecular block copolymers with a high hydrophobic / hydrophilic block ratio and crosslinked with dihaloalkanes for three-dimensional confined assembly. This step allows for the joint control of the packing parameters of the block copolymers from both volume fraction and effective cross-sectional area dimensions, resulting in a more refined range of packing parameters, reaching values ​​greater than 1, ultimately facilitating the formation of a multilayer perforated bicontinuous structure. Because the phase window of the bicontinuous structure is narrow, the assembly conditions and control parameters are required to be precise, making it difficult to obtain a perforated layered structure by traditional assembly methods. However, the preparation method of this invention uses simple materials, is easy to operate, has mild experimental conditions, and has good controllability. It solves the technical problem that traditional block copolymers are difficult to obtain ordered perforated layered mesoporous microspheres by assembly and have strict requirements for assembly experimental conditions.

[0051] (3) The ordered multilayer perforated mesoporous microspheres provided by this invention have an adjustable number of layers and pores. As the microsphere size increases, the number of layers and pores also increases. Notably, when the number of layers in the layered structure of the microsphere is 1, the number of pores in the microsphere is 1 to 9. Therefore, in addition to obtaining ordered multilayer perforated mesoporous microspheres with different numbers of layers, it is also possible to obtain small-sized monolayer mesoporous microspheres with novel structures, including mesoporous microspheres with different numbers of pores, such as single-pore, double-pore, triple-pore, quadruple-pore, and pentaple-pore microspheres. These small-sized monolayer mesoporous microspheres can be used to reveal the formation mechanism, pore morphology, and internal structure of ordered multilayer perforated mesoporous microspheres.

[0052] (4) In this invention, poly(4-vinylpyridine) is preferably used as the hydrophilic block, which enriches the surface and pore walls of the mesoporous microspheres with pyridine active groups, thereby further functionalizing them. For example, the mesoporous microspheres can interact with precursors of various functional substances, including precursors of metal nanoparticles and inorganic oxides. Suitable metal nanoparticle precursors include palladium chloride, potassium tetrachloroplatinate, chloroplatinic acid, chloroauric acid, copper chloride, cobalt chloride, nickel chloride, etc. Suitable inorganic oxides include tetraethyl orthosilicate, tetraisobutyl titanate, etc.

[0053] (5) The ordered multilayer perforated mesoporous microspheres provided by the present invention can be applied to fields such as precious metal recovery, targeted adsorption of precious metal ions, energy storage and conversion devices, and drug delivery. Attached Figure Description

[0054] Figure 1The image shown is a transmission electron microscope image of the ordered multilayer perforated mesoporous microspheres with 4 layers prepared in Example 1 of the present invention. The inset is a 3D schematic diagram of the microspheres.

[0055] Figure 2 (a) is a transmission electron microscope image of the ordered multilayer perforated mesoporous microspheres with 3 layers prepared in Example 2 of the present invention, and the inset is its 3D schematic diagram; Figure 2 Image (b) is a scanning electron microscope image of the ordered multilayer perforated mesoporous microspheres with 3 layers prepared in Example 2 of the present invention;

[0056] Figure 3 The image shown is a transmission electron microscope image of the ordered multilayer perforated mesoporous microspheres with 6 layers prepared in Example 3 of the present invention. The inset is a 3D schematic diagram of the microspheres.

[0057] Figure 4 The image shown is a transmission electron microscope image of the ordered multilayer perforated mesoporous microspheres with two layers prepared in Example 4 of the present invention. The inset is a 3D schematic diagram of the microspheres.

[0058] Figure 5 (a) in the figure is a state diagram after multiple centrifugations in step (4) of embodiment 4 of the present invention. Figure 5 Image (b) shows the state of the ordered multilayer perforated mesoporous microspheres prepared in Example 4 of this invention after adding an aqueous solution of chloroauric acid and stirring for 12 hours. Figure 5 (c) in the diagram is the state diagram of the solution in (b) after centrifugation. Figure 5 (d) in the diagram is the state diagram of a hexadecyltrimethylammonium bromide solution. Figure 5 (e) in the diagram represents the state of the solution in (d) after it has been mixed with the precipitate in (c) and ultrasonically dispersed. Figure 5 (f) in the diagram represents the state of the solution in (e) after standing for 12 hours. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0060] Example 1

[0061] (1) Prepare a solution with PS as the solute. 51k -b-P4VP 18k Prepare a chloroform solution with a concentration of 10.0 mg / mL. The solute is 3-pentadecanylphenol, and the concentration is 10.0 mg / mL. (The last part, "PS," appears to be an unrelated fragment and is omitted from the translation.) 51k-b-P4VP 18k Based on the molar amount of the pyridine group, PS 51k -b-P4VP 18k Solution, 3-pentadecanylphenol solution according to PS 51k -b-P4VP 18k The mixture was stirred at room temperature for 12 hours with 3-pentadecanylphenol in a molar ratio of 1:1.2 to form a comb-like supramolecular block copolymer solution.

[0062] (2) Using PS 51k -b-P4VP 18k Based on the molar amount of pyridine groups, the above comb-like supramolecular block copolymer solution was mixed with 1,5-dibromopentane according to PS... 51k -b-P4VP 18k The mixture was mixed with 1,5-dibromopentane at a molar ratio of 1:0.4 and stirred at 25°C for 12 hours to form a composite supramolecular block copolymer solution.

[0063] (3) Prepare an aqueous solution of polyvinyl alcohol with a concentration of 3.0 mg / mL. Mix the above-mentioned composite supramolecular block copolymer solution and the aqueous solution of polyvinyl alcohol at a volume ratio of 1:10, and manually pass the mixture through a membrane emulsification device 14 times to obtain an emulsion with a membrane pore size of 0.45 μm. Place the obtained emulsion in an open environment at 30°C for 36 hours until the organic solvent is completely evaporated, and obtain a solution of spherical polymer microspheres with an internal layered structure.

[0064] (4) Take the above-mentioned spherical polymer microsphere solution with an internal layered structure, add at least twice the volume of ethanol to it, centrifuge, then take the precipitate, disperse it with ethanol, and centrifuge it several times to remove the supernatant, and you can obtain ordered multilayer perforated mesoporous microspheres.

[0065] Electron microscopy scanning of ordered multilayer perforated mesoporous microspheres yielded the following results: Figure 1 As shown. From Figure 1 As can be seen, the obtained ordered multilayer perforated mesoporous microspheres have 4 layers, a particle size of 400.1 nm, approximately 110 columnar pores, a pore size of 21.3 nm, a layered structure thickness of 39.8 nm, and a period of 58.8 nm for the columnar pores.

[0066] Example 2

[0067] (1) Prepare a solution with PS as the solute. 51k -b-P4VP 18k Prepare a chloroform solution with a concentration of 10.0 mg / mL. The solute is 3-pentadecanylphenol, and the concentration is 10.0 mg / mL. (The last part, "PS," appears to be an unrelated fragment and is omitted from the translation.) 51k-b-P4VP 18k Based on the molar amount of the pyridine group, PS 51k -b-P4VP 18k Solution, 3-pentadecanylphenol solution according to PS 51k -b-P4VP 18k The mixture was stirred at room temperature for 12 hours with 3-pentadecanylphenol in a molar ratio of 1:1.2 to form a comb-like supramolecular block copolymer solution.

[0068] (2) Using PS 51k -b-P4VP 18k Based on the molar amount of pyridine groups, the above comb-like supramolecular block copolymer solution was mixed with 1,5-dibromopentane according to PS... 51k -b-P4VP 18k The mixture was mixed with 1,5-dibromopentane at a molar ratio of 1:0.4 and stirred at 25°C for 12 hours to form a composite supramolecular block copolymer solution.

[0069] (3) Prepare an aqueous solution of polyvinyl alcohol with a concentration of 3.0 mg / mL. Mix the above-mentioned composite supramolecular block copolymer solution and the aqueous solution of polyvinyl alcohol at a volume ratio of 1:10, and manually pass the mixture through a membrane emulsification device 18 times to obtain an emulsion with a membrane pore size of 0.45 μm. Place the obtained emulsion in an open environment at 30°C for 36 hours until the organic solvent is completely evaporated, and obtain a solution of spherical polymer microspheres with an internal layered structure.

[0070] (4) Take the above-mentioned spherical polymer microsphere solution with an internal layered structure, add at least twice the volume of ethanol to it, centrifuge, then take the precipitate, disperse it with ethanol, and centrifuge it several times to remove the supernatant, and you can obtain ordered multilayer perforated mesoporous microspheres.

[0071] Electron microscopy scanning of ordered multilayer perforated mesoporous microspheres yielded the following results: Figure 2 As shown. From Figure 2 As can be seen, the obtained ordered multilayer perforated mesoporous microspheres have 3 layers, a particle size of 300.0 nm, approximately 58 columnar pores, a pore size of 22.6 nm, a layered structure thickness of 40.2 nm, and a period of 60.7 nm for the columnar pores.

[0072] Example 3

[0073] (1) Prepare a solution with PS as the solute. 51k -b-P4VP 18k Prepare a 10.0 mg / mL solution of dichloromethane. Prepare a 10.0 mg / mL solution of chloroform with 3-pentadecanylphenol as the solute. (The last part, "PS," appears to be incomplete and unrelated to the preceding text. It has been left as is.) 51k-b-P4VP 18k Based on the molar amount of the pyridine group, PS 51k -b-P4VP 18k Solution, 3-pentadecanylphenol solution according to PS 51k -b-P4VP 18k The mixture was stirred at room temperature for 12 hours with 3-pentadecanylphenol in a molar ratio of 1:1.2 to form a comb-like supramolecular block copolymer solution.

[0074] (2) Using PS 51k -b-P4VP 18k Based on the molar amount of pyridine groups, the above comb-like supramolecular block copolymer solution was mixed with 1,5-dibromopentane according to PS... 51k -b-P4VP 18k The mixture was mixed with 1,5-dibromopentane at a molar ratio of 1:0.4 and stirred at 25°C for 12 hours to form a composite supramolecular block copolymer solution.

[0075] (3) Prepare an aqueous solution of polyvinyl alcohol with a concentration of 3.0 mg / mL. Mix the above-mentioned composite supramolecular block copolymer solution and the aqueous solution of polyvinyl alcohol at a volume ratio of 1:10, and manually pass the mixture through a membrane emulsifier 10 times to obtain an emulsion with a membrane pore size of 0.45 μm. Place the obtained emulsion in an open environment at 30°C for 36 hours until the organic solvent is completely evaporated, and obtain a solution of spherical polymer microspheres with an internal layered structure.

[0076] (4) Take the above-mentioned spherical polymer microsphere solution with an internal layered structure, add at least twice the volume of ethanol to it, centrifuge, then take the precipitate, disperse it with ethanol, and centrifuge it several times to remove the supernatant, and you can obtain ordered multilayer perforated mesoporous microspheres.

[0077] Electron microscopy scanning of ordered multilayer perforated mesoporous microspheres yielded the following results: Figure 3 As shown. From Figure 3 As can be seen, the obtained ordered multilayer perforated mesoporous microspheres have 6 layers, a particle size of 592.2 nm, approximately 700 columnar pores, a pore size of 23.8 nm, a layered structure thickness of 38.7 nm, and a period of 60.6 nm for the columnar pores.

[0078] Example 4

[0079] (1) Prepare a solution with PS as the solute. 51k -b-P4VP 18k Prepare a chloroform solution with a concentration of 5 mg / mL. The solute is 3-pentadecanylphenol, and the concentration is 5 mg / mL. (The last part, "PS," appears to be an unrelated fragment and is omitted from the translation.) 51k -b-P4VP18k Based on the molar amount of the pyridine group, PS 51k -b-P4VP 18k Solution, 3-pentadecanylphenol solution according to PS 51k -b-P4VP 18k The mixture was stirred at room temperature for 12 hours with 3-pentadecanylphenol in a molar ratio of 1:1.2 to form a comb-like supramolecular block copolymer solution.

[0080] (2) Using PS 51k -b-P4VP 18k Based on the molar amount of pyridine groups, the above comb-like supramolecular block copolymer solution was mixed with 1,5-dibromopentane according to PS... 51k -b-P4VP 18k The mixture was mixed with 1,5-dibromopentane at a molar ratio of 1:0.4 and stirred at 25°C for 12 hours to form a composite supramolecular block copolymer solution.

[0081] (3) Prepare an aqueous solution of polyvinyl alcohol with a concentration of 3.0 mg / mL. Mix the above-mentioned composite supramolecular block copolymer solution and the aqueous solution of polyvinyl alcohol at a volume ratio of 1:10, and manually pass the mixture through a membrane emulsification device 30 times to obtain an emulsion with a membrane pore size of 0.2 μm. Place the obtained emulsion in an open environment at 30°C for 36 hours until the organic solvent is completely evaporated, and obtain a solution of spherical polymer microspheres with an internal layered structure.

[0082] (4) Take the above-mentioned spherical polymer microsphere solution with an internal layered structure, add at least twice the volume of ethanol, centrifuge, then take the precipitate, disperse it with ethanol, and centrifuge it several more times. See the morphology section below. Figure 5 As shown in (a), after removing the supernatant, ordered multilayer perforated mesoporous microspheres can be obtained.

[0083] Electron microscopy scanning of ordered multilayer perforated mesoporous microspheres yielded the following results: Figure 4 As shown. From Figure 4 As can be seen, the obtained ordered multilayer perforated mesoporous microspheres have 2 layers, a particle size of 213.9 nm, approximately 36 columnar pores, a pore size of 20.5 nm, a layered structure thickness of 37.6 nm, and a period of 61.8 nm for the columnar pores.

[0084] Take the ordered multilayer perforated mesoporous microspheres prepared in Example 4, add an appropriate amount of aqueous chloroauric acid solution to them, and stir for 12 hours. The resulting solution (see...) Figure 5 (b) contains ordered multilayer perforated mesoporous microspheres that can adsorb a large number of gold ions (see [reference]). Figure 5(b) Illustration). Centrifuging the solution reveals that the bottom precipitate changes from its initial white color to brown, indicating the adsorbed gold ions in the mesoporous microspheres (see [reference]). Figure 5 (c) Remove the supernatant and retain the precipitate. Prepare a 3 mg / mL solution of hexadecyltrimethylammonium bromide (CTAB) (see [reference]). Figure 5 (d) is used for desorption of gold ions. After mixing the CTAB solution with the above precipitate and dispersing it evenly by ultrasonication, the solution immediately turns yellow (see [reference]). Figure 5 (e)), after standing for 12 hours, the solution is centrifuged, and the bottom precipitate obtained (see [reference]). Figure 5 (f)) It can be used to recover mesoporous microspheres. The results show that the obtained ordered multilayer perforated mesoporous microspheres can be used in the field of precious metal recovery, serving as a selective adsorbent to separate and recover precious metal elements (such as gold) in solutions or waste liquids. It can also achieve the desorption of metal ions, and is expected to serve as a highly efficient adsorbent for precious metals.

[0085] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ordered multilayer perforated mesoporous microsphere, characterized in that, The microspheres have regular spherical geometric shapes; The framework structure inside the microspheres presents an onion-like concentric layer nested configuration, which is composed of multiple independent, sequentially wrapped layer structures; The interior of each independent layer structure contains a highly ordered array of columnar through holes with hexagonal phase P6mm symmetry distribution, which forms a regular and periodic hexagonal honeycomb channel network in the respective layer structure; The columnar through holes penetrate the layer structure in which they are located, and in three-dimensional space, the columnar through holes between different layer structures and the columnar through holes within the same layer structure are interconnected, forming a three-dimensional interconnected pore network throughout the interior of the microspheres.

2. The ordered multilayer perforated mesoporous microspheres according to claim 1, characterized in that, The particle size of the ordered multilayer perforated mesoporous microspheres is 0.02-10 μm, the pore size of the columnar through holes is the same, the pore size of the columnar through holes is 2-100 nm; the thickness of the layer structure is 5-100 nm; the period of the columnar through holes is 5-100 nm; Preferably, the particle size of the ordered multilayer perforated mesoporous microspheres is 0.05-1 μm; Preferably, the pore size of the columnar through holes is 5-50 nm.

3. The ordered multilayer perforated mesoporous microspheres according to claim 1, characterized in that, The number of layer structures of the ordered multilayer perforated mesoporous microspheres is 1-20 layers; the number of columnar through holes of the ordered multilayer perforated mesoporous microspheres is 1-2000.

4. The ordered multilayer perforated mesoporous microspheres according to any one of claims 1 to 3, characterized in that, The framework surface of the ordered multilayer perforated mesoporous microspheres is loaded with active groups, and the framework surface of the ordered multilayer perforated mesoporous microspheres includes the outer surface of the ordered multilayer perforated mesoporous microspheres, the interlayer interface, and the inner surface of all columnar through holes; Preferably, the active group is a pyridine group.

5. The method of preparing ordered multilayered perforated mesoporous microspheres according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: (1) Dissolve the two-block copolymer in a water-insoluble organic solvent to obtain a two-block copolymer solution, dissolve the water-insoluble alkane small molecule in a water-insoluble organic solvent to obtain an alkane small molecule solution; mix the two-block copolymer solution and the alkane small molecule solution, and stir for a period of time to obtain a comb-like supramolecular block copolymer solution based on hydrogen bonding; (2) Mix the comb-like supramolecular block copolymer solution prepared in step (1) and a halogenated alkane crosslinking agent, stir for a period of time, and crosslink to obtain a composite supramolecular block copolymer solution; (3) Use the composite supramolecular block copolymer solution prepared in step (2) to prepare a spherical polymer microsphere solution with a layered structure inside by using an emulsion-solvent evaporation method; (4) Mix the spherical polymer microsphere solution prepared in step (3) and ethanol, and centrifuge and purify to obtain the ordered multilayer perforated mesoporous microspheres.

6. The production method according to claim 5, wherein The two block copolymers in step (1) include a polymer for constituting a dispersed phase and a polymer for constituting a continuous phase; the polymer for constituting a dispersed phase is poly(styrene), poly(isoprene), poly(acrylate) or poly(butadiene), and the polymer for constituting a continuous phase is poly(2-vinylpyridine) or poly(4-vinylpyridine); the molecular weight of the hydrophobic segment of the polymer for constituting a dispersed phase in the two block copolymers is 5000-100000, and the molecular weight of the hydrophilic segment of the polymer for constituting a continuous phase in the two block copolymers is 5000-100000; the ratio of the molecular weight of the hydrophobic segment of the polymer for constituting a dispersed phase to the molecular weight of the hydrophilic segment of the polymer for constituting a continuous phase in the two block copolymers is 2.8-3.2; Preferably, the organic solvent in step (1) is at least one of toluene, dichloromethane and chloroform; Preferably, the alkane small molecule in step (1) is 3-pentadecylphenol; Preferably, the ratio of the molar amount of the two block copolymers to the molar amount of the alkane small molecule in step (1) is 1:(1.1-1.3), and the molar amount of the two block copolymers is the molar amount of the pyridine group; Preferably, the temperature of the stirring in step (1) is 10-35℃, and the stirring time is 12-48h.

7. The preparation method according to claim 5, characterized in that, The halogenated alkane in step (2) is a dihalogenated alkane containing one halogen element at each end of the carbon chain; preferably, the halogen element contained in the halogenated alkane is at least one of bromine and iodine; preferably, the halogenated alkane is 1,2-diiodomethane, 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane or 1,8-dibromooctane; Preferably, the ratio of the molar amount of the two block copolymers in step (1) to the molar amount of the halogenated alkane in step (2) is 1:(0.3-0.8), and the molar amount of the two block copolymers is the molar amount of the pyridine group; Preferably, the temperature of the stirring in step (2) is 10-35℃, and the stirring time is 4-48h.

8. The preparation method according to claim 5, characterized in that, Step (3) specifically comprises: mixing the complex supramolecular block copolymer solution prepared in step (2) and an aqueous solution of a surfactant, and then performing emulsification to obtain an emulsion, and placing the emulsion in an environment at 20-35℃ for open evaporation, so as to obtain a spherical polymer microsphere solution with a layered structure in the interior after the organic solvent is completely volatilized; Preferably, the surfactant is polyvinyl alcohol; Preferably, the concentration of the aqueous solution of the surfactant is 1.0-10.0mg / mL, and the volume ratio of the complex supramolecular block copolymer solution to the aqueous solution of the surfactant is 1:(5-15).

9. The preparation method according to claim 5, characterized in that, The volume ratio of the ethanol to the spherical polymer microsphere solution in step (4) is (1.6-3):

1.

10. The ordered multilayer perforated mesoporous microsphere according to any one of claims 1-4 or prepared by the preparation method according to any one of claims 5-9 is applied in the recovery of noble metals, the targeted adsorption of noble metal ions, energy storage and conversion devices, and drug delivery.

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