Porous snowman-like janus particles, porous patchy patchy particles, and methods of making the same

Abstract

The present application relates to a kind of porous snowman-shaped Janus particles, porous patchy Patchy particles and preparation method thereof.The porous particles of the present application have through hole, including microsphere portion and one or more protruding portions on the surface of the microsphere portion, wherein the microsphere portion contains crosslinked polymer, the protruding portion contains silicon oxide, the porous particles are snowman-shaped Janus particles or patchy Patchy particles, wherein each of the snowman-shaped Janus particles has a microsphere portion and a protruding portion;Each of the patchy Patchy particles has a microsphere portion and a plurality of protruding portions.The porous snowman-shaped Janus particles and porous patchy Patchy particles of the present application have wide application prospects in many fields such as oil-water emulsification, catalytic carrier, wastewater treatment, pharmaceutical industry, chemical industry and the like.

Description

Technical Field

[0001] This invention relates to the field of polymers, specifically to a porous snowman-shaped Janus particle, a porous patch-shaped Patchy particle, and a method for preparing the same. Background Technology

[0002] With the rapid development of science and technology, the demand for materials is becoming more diversified. Materials with simple composition and structure and singular properties are increasingly unable to meet human needs. The search for a new type of material that can have multiple compositions and functions on the same surface has become a research hotspot for many scientists.

[0003] Janus materials, which combine two different components or structures and are strictly partitioned, have become a hot research topic in the field of composite materials. By expanding the preparation methods of Janus particles, Janus materials with novel structures and diverse properties have been prepared in recent years, covering semiconductor materials, magnetically responsive materials, and photosensitive materials, which can be applied in multiple fields such as catalysis, blending, particulate emulsifiers, and drug delivery.

[0004] Patent document 1 discloses a magnetic snowman-shaped asymmetric Janus particle, which includes a hydrophilic portion and an oleophilic portion that respectively constitute two spheres of the snowman-shaped particle. The hydrophilic portion includes hydrophilically modified polymer composite microspheres and magnetic nanoparticles attached to the surface of the polymer composite microspheres. The oleophilic portion includes hydrophobically modified silica.

[0005] "Patchy" particles, also known as patchy particles, have specific functional regions on their surface that appear as patches. The area, number, topological shape, and chemical composition of these patch regions on the surface of patchy particles are key factors determining the particle properties.

[0006] Patent document 2 discloses a patch structure colloidal particle comprising cross-linked polymer particles and a plurality of SiO2 patch portions located on the surface of the cross-linked polymer particles. The cross-linked polymer particles are composed of a template polymer particle and a polymer formed by a cross-linking agent, wherein at least a portion of the molecular chains of the template polymer particle and the molecular chains of the polymer formed by the cross-linking agent interpenetrate each other.

[0007] Porous microspheres, as an important porous material, typically possess high specific surface area and abundant pore structure, providing more active sites. Therefore, they have a wide range of applications.

[0008] References

[0009] Patent Document 1: CN114736322A

[0010] Patent Document 2: CN112521556A Summary of the Invention

[0011] The problem the invention aims to solve

[0012] There are currently no reports of particles that can simultaneously possess the properties of snowman-shaped Janus particles or patchy particles as well as porous polymer particles.

[0013] Therefore, the purpose of this invention is to provide porous snowman-shaped Janus particles and porous patchy particles and their preparation methods.

[0014] Solution for solving the problem

[0015] To address the aforementioned problems, the inventors conducted long-term and in-depth research and proposed to first obtain snowman-shaped Janus or patchy particles composed of silica and polymer through free radical suspension polymerization and synergistic oil-water interface sol-gel reaction. Then, by removing the linear polymer, porous particles with through-holes are obtained, thus completing the present invention.

[0016] Specifically, the present invention solves the problems of the present invention through the following solutions.

[0017] [1] A porous particle having through-holes, comprising a microsphere portion and one or more protrusions located on the surface of the microsphere portion, wherein the microsphere portion comprises a cross-linked polymer and the protrusions comprise silicon oxide.

[0018] The porous particles are snowman-shaped Janus particles or patchy particles.

[0019] Each of the snowman-shaped Janus particles has a microsphere portion and a protrusion portion; each of the patchy particles has a microsphere portion and multiple protrusion portions.

[0020] [2] According to the porous particles of [1], wherein the crosslinked polymer comprises structural units derived from monomers and structural units derived from crosslinking agents, wherein the monomers are at least one selected from styrene monomers and (meth)acrylate monomers, and the crosslinking agents are at least one selected from divinylbenzene crosslinking agents and (meth)acrylate crosslinking agents.

[0021] [3] According to the porous particles described in [1], wherein the average particle size of the porous particles is 50–300 μm; and / or,

[0022] The porous particles have a pore size of 20–200 nm; and / or,

[0023] The porosity of the porous particles is 10–50%; and / or,

[0024] The specific surface area of ​​the porous particles is 1–50 m². 2 / g.

[0025] [4] According to the porous particles of [1], wherein the protrusions are formed by polymerization and sol-gel reaction of monomers having an alkoxysilane structure, wherein the monomers having an alkoxysilane structure have (meth)acryloyloxy and alkoxysilyl groups.

[0026] [5] The method for preparing porous particles according to any one of [1] to [4] includes a polymerization step and a pore-forming step:

[0027] The polymerization step includes the following sub-steps:

[0028] (P-1) Dissolve the dispersant in water to obtain an aqueous phase;

[0029] (P-2) A linear polymer, monomer, crosslinking agent and initiator are mixed to obtain an oil phase;

[0030] (P-3) The aqueous phase and oil phase are mixed and dispersed to obtain a dispersion in which the oil phase is dispersed in the aqueous phase;

[0031] (P-4) Under polymerization conditions, monomers and crosslinking agents undergo a polymerization reaction to obtain polymer microspheres;

[0032] (P-5) A monomer having an alkoxysilane structure, an emulsifier, an initiator, and water are mixed to obtain a monomer emulsion;

[0033] (P-6) The obtained polymer microspheres were dispersed in water and mixed with monomer emulsion under polymerization conditions to carry out seed swelling polymerization reaction, resulting in snowman-shaped Janus particles or patchy particles.

[0034] (P-7) When a pH adjuster is added, the alkoxysilane undergoes a sol-gel reaction;

[0035] The pore-forming step includes: contacting the snowman-shaped Janus particles or patchy particles obtained in the polymerization step with a solvent, so that the linear polymer contained therein dissolves into the solvent, thereby forming the through-hole.

[0036] [6] According to the preparation method described in [5], wherein,

[0037] In sub-step (P-1), the dispersant is at least one selected from polyvinyl alcohol, gelatin, starch, polyacrylic acid, and sulfonated polystyrene; the mass ratio of water to dispersant in the aqueous phase is 50 / 1 to 10 / 1;

[0038] In sub-step (P-2), the mass ratio of monomer to linear polymer is 10 / 1 to 4 / 1; the volume ratio of monomer to crosslinking agent is 40 / 1 to 5 / 1; and the mass ratio of monomer to initiator is 200 / 1 to 50 / 1.

[0039] In sub-step (P-3), the volume ratio of the aqueous phase to the oil phase is 5 / 1 to 3 / 1;

[0040] In sub-step (P-5), the emulsifier is at least one selected from sodium dodecyl sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate; the initiator is at least one selected from sodium persulfate, potassium persulfate, and ammonium persulfate; the mass ratio of the monomer having an alkoxysilane structure to water is 1 / 20 to 1 / 5; the mass ratio of the emulsifier to water is 1 / 1000 to 5 / 1000; and the mass ratio of the initiator to water is 1 / 1000 to 5 / 1000.

[0041] In sub-step (P-6), the mass ratio of polymer microspheres to monomers with alkoxysilane structures in the monomer emulsion is 1 / 2 to 2 / 1;

[0042] In sub-step (P-7), the pH of the aqueous phase is 7 to 11, and the pH adjuster is at least one selected from ammonia (NH3), sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate.

[0043] [7] According to the preparation method described in [5], in sub-step (P-4), the polymerization conditions include: polymerization temperature of 60-80℃, stirring rate of 100-300rpm, and reaction time of 5-8h; in sub-step (P-6), the polymerization conditions include: polymerization temperature of 60-80℃, and reaction time of 5-8h.

[0044] [8] According to the preparation method described in [5], the solvent used in the pore-forming step is at least one selected from glacial acetic acid, acetone, ethylene glycol, and N,N-dimethylformamide, and the contact time with the solvent is 1 to 8 hours.

[0045] [9] Porous particles prepared by any one of [5] to [8].

[0046]

[10] The porous particles according to any one of [1] to [4] and [9] are used in catalysts, oil-water emulsification, biomedical applications, and wastewater treatment.

[0047] The effects of the invention

[0048] The porous snowman-shaped Janus particles and porous patchy particles of the present invention have abundant pore structures inside, which are three-dimensionally integrated into the material. They have large pore size and specific surface area, are insoluble in acids, alkalis, and organic solvents such as ethanol, acetone and hydrocarbons, and have excellent thermal stability and chemical stability.

[0049] The porous snowman-shaped Janus particles and porous patchy particles of the present invention have an asymmetric structure, and therefore can exist stably at the asymmetric interface of oil and water.

[0050] The porous snowman-shaped Janus particles and porous patchy particles of the present invention have broad application prospects in many fields such as oil-water emulsification, catalyst carriers, wastewater treatment, pharmaceutical industry, and chemical industry.

[0051] The preparation method of this invention is simple, easy to operate, uses readily available and low-cost raw materials, and can achieve large-scale batch production. Furthermore, this method can control the size and pore size of porous snowman-shaped Janus particles and porous patchy particles. Attached Figure Description

[0052] Figure 1 The image shows a scanning electrolytic image of the particles obtained in Example 1.

[0053] Figure 2 This is a scanning electrolytic image of the particles obtained in Example 3. Detailed Implementation

[0054] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0055] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0056] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0057] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0058] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0059] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0060] In this specification, the numerical ranges indicated by "above" and "below" refer to the ranges including the endpoint values. The numerical ranges indicated by "greater than" and "less than" refer to the ranges excluding the endpoint values.

[0061] In this specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes both the scenario in which the event occurs and the scenario in which the event does not occur.

[0062] In this specification, the “size” described for porous polymer microspheres refers to the particle size of the microspheres, which can be measured using third-party software such as ImageJ and electron scanning microscope images. The average particle size and its distribution can also be measured using a laser particle size analyzer.

[0063] All unit names used in this manual are international standard unit names, and unless otherwise specified, "%" indicates mass percentage content.

[0064] Porous particles

[0065] One object of the present invention is to provide a porous particle having through-pores, comprising a microsphere portion and one or more protrusions located on the surface of the microsphere portion, wherein the microsphere portion comprises a cross-linked polymer and the protrusions comprise silicon oxide.

[0066] The porous particles are snowman-shaped Janus particles or patchy particles.

[0067] Each of the snowman-shaped Janus particles has a microsphere portion and a protrusion portion; each of the patchy particles has a microsphere portion and multiple protrusion portions.

[0068] In some embodiments, the protrusion is formed by polymerization and sol-gel reactions of a monomer having an alkoxysilane structure, wherein the monomer having an alkoxysilane structure has (meth)acryloyloxy and alkoxysilyl groups.

[0069] In some embodiments, the average particle size of the porous particles of the present invention is 50–300 μm.

[0070] In some embodiments, the porous particles of the present invention have a pore size of 20–200 nm.

[0071] In some embodiments, the porosity of the porous particles of the present invention is 10-50%, preferably 15-40%.

[0072] In some embodiments, the specific surface area of ​​the porous particles of the present invention is 1–50 m². 2 / g.

[0073] In this specification, the “pore size,” “porosity,” and “specific surface area” of the particles are determined by the BET method.

[0074] The snowman-shaped Janus particles and patchy particles of the present invention have structures generally known in the art.

[0075] On one hand, the porous particles of the present invention are porous snowman-shaped Janus particles, which include two parts constituting the head and body of the snowman, namely a protruding part and a microsphere part.

[0076] On the other hand, the porous particles of the present invention are patchy particles, which include a microsphere portion and multiple protrusion portions, the multiple protrusion portions being patch structures on the surface of the particles, each protrusion portion being a patch structure, which can have any shape.

[0077] [Microsphere section]

[0078] In the porous particles of the present invention, the microsphere portion is spherical. In this specification, "spherical" includes true spherical and near-spherical shapes, with a sphericity coefficient of 0.5 or higher, preferably 0.8 or higher.

[0079] In the porous particles of the present invention, the microsphere portion has a porous structure with through-holes, and preferably has a three-dimensional pore structure.

[0080] Based on the mass of the porous particles, the content of the microsphere portion is 50-90%.

[0081] In the porous particles of the present invention, the microsphere portion comprises a cross-linked polymer. The cross-linked polymer comprises structural units derived from monomers and structural units derived from cross-linking agents. In this specification, "structural units derived from monomers" refers to structural units formed by a reaction (polymerization reaction) of monomers, and "structural units derived from cross-linking agents" refers to structural units formed by a reaction (cross-linking reaction) of cross-linking agents.

[0082] Preferably, the monomer is a free radical polymerizable monomer. Specifically, the monomer is a compound having a single free radical polymerizable group.

[0083] Preferably, the monomer is at least one selected from styrene monomers and (meth)acrylate monomers.

[0084] Styrene monomers refer to styrene and its derivatives, including but not limited to styrene and substituted styrene. For substituted styrene, the substituents can be alkyl, alkenyl, alkoxy, halogen, etc., preferably having 1 to 5 carbon atoms, and may further include the aforementioned substituents, such as halogens. Specifically, the styrene monomers of this invention include one or more combinations of styrene, methylstyrene, ethylstyrene, chloromethylstyrene, etc.

[0085] (Meth)acrylate monomers refer to (meth)acrylates and their derivatives, including but not limited to alkyl (meth)acrylates.

[0086] For alkyl methacrylates, such as (meth)acrylate C1-C 12 Alkyl esters, specific examples of which include, but are not limited to, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-methyl-2-acrylate-2-(2-methoxyethoxy)ethyl ester, ethyl cyanoacrylate, etc.

[0087] In this specification, structural units derived from monomers also include structural units that, although not directly derived from the monomers described above, have the same structure as those directly derived from the monomers described above.

[0088] The crosslinking agent is selected from at least one of divinylbenzene-based crosslinking agents and (meth)acrylate-based crosslinking agents.

[0089] Divinylbenzene-based crosslinking agents refer to divinylbenzene and its derivatives, including but not limited to divinylbenzene, trivinylbenzene, and divinylnaphthalene.

[0090] (Meth)acrylate crosslinking agents refer to compounds having two or more (meth)acryloyloxy groups, including but not limited to ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, pentanediol di(meth)acrylate, etc.; trifunctional (meth)acrylates, such as pentaerythritol tri(meth)acrylate, trihydroxymethane tri(meth)acrylate, and glycerol tri(meth)acrylate, etc.; tetrafunctional (meth)acrylates, such as pentaerythritol tetra(meth)acrylate; pentafunctional (meth)acrylates, such as dipentaerythritol penta(meth)acrylate; and hexafunctional (meth)acrylates, such as dipentaerythritol hexa(meth)acrylate, etc.

[0091] [Raised portion]

[0092] The porous particles of the present invention comprise one or more protruding portions, the protruding portions comprising silicon oxide. The silicon oxide is a substance having silicon-oxygen bonds, which can be formed, for example, from monomers having an alkoxysilane structure via polymerization and sol-gel reactions.

[0093] Preferably, the monomer having an alkoxysilane structure has (meth)acryloyloxy and alkoxysilyl groups.

[0094] Preferably, the monomer having an alkoxysilane structure is an alkoxysilane having a (meth)acryloyloxyalkyl group, including dialkoxysilanes, trialkoxysilanes, etc. Specific examples include γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxypropyltripropoxysilane, γ-(meth)acryloyloxypropylmethyldimethoxysilane, γ-(meth)acryloyloxypropylmethyldiethoxysilane, etc.

[0095] The protruding portion is the part that protrudes from the surface of the microsphere portion. The present invention does not impose any particular limitation on the shape of the protruding portion; its projection onto the surface of the microsphere portion can be, for example, a circle or any other shape.

[0096] Based on the mass of the porous particles, the content of the protruding portion is 10–50% by mass.

[0097] For patchy particles, the number of protrusions can be 2 to 20, such as 3 to 18, 4 to 16, 5 to 14, 6 to 12, 8 to 10, etc.

[0098] <Preparation Method>

[0099] One object of the present invention is to provide a method for preparing porous particles of the present invention, characterized in that it includes a polymerization step and a pore-forming step:

[0100] The polymerization step includes the following sub-steps:

[0101] (P-1) Dissolve the dispersant in water to obtain an aqueous phase;

[0102] (P-2) A linear polymer, monomer, crosslinking agent and initiator are mixed to obtain an oil phase;

[0103] (P-3) The aqueous phase and oil phase are mixed and dispersed to obtain a dispersion in which the oil phase is dispersed in the aqueous phase;

[0104] (P-4) Under polymerization conditions, monomers and crosslinking agents undergo a polymerization reaction to obtain polymer microspheres;

[0105] (P-5) A monomer having an alkoxysilane structure, an emulsifier, an initiator, and water are mixed to obtain a monomer emulsion;

[0106] (P-6) The obtained polymer microspheres are dispersed in water and mixed with monomer emulsion dropwise under polymerization conditions to carry out seed swelling polymerization reaction, resulting in snowman-shaped Janus particles or patchy particles.

[0107] (P-7) Adding a pH adjuster causes the alkoxysilane to undergo a sol-gel reaction, resulting in snowman-shaped Janus particles or patchy particles.

[0108] The pore-forming step includes: contacting the snowman-shaped Janus particles or patchy particles obtained in the polymerization step with a solvent, so that the linear polymer contained therein dissolves into the solvent, thereby forming the through-hole.

[0109] The following describes each step of the preparation method of the present invention.

[0110] Aggregation Steps

[0111] In the preparation method of the present invention, a cross-linked polymer is formed by free radical polymerization of monomers and cross-linking agents through a polymerization step, and a protruding portion is formed by polymerization of monomers with alkoxysilane structures and sol-gel reaction, wherein silicon oxide is formed by sol-gel reaction.

[0112] In this invention, the polymerization step is carried out by suspension polymerization.

[0113] [Sub-step (P-1)]

[0114] In sub-step (P-1), an aqueous phase containing a dispersant is prepared.

[0115] This invention does not impose any particular limitation on the dispersant; any dispersant commonly used in suspension polymerization can be used. Preferably, the dispersant is at least one selected from polyvinyl alcohol, gelatin, starch, polyacrylic acid, and sulfonated polystyrene.

[0116] In some embodiments, the mass ratio of water to dispersant in the aqueous phase is 50 / 1 to 10 / 1, preferably 40 / 1 to 20 / 1.

[0117] [Sub-step (P-2)]

[0118] In sub-step (P-2), an oil phase comprising a linear polymer, monomer, crosslinking agent and initiator is prepared.

[0119] In this invention, linear polymers are not particularly limited; specifically, the linear polymers include (meth)acrylate polymers. These (meth)acrylate polymers can be commercially available or prepared by polymerization of (meth)acrylate monomers.

[0120] Specifically, (meth)acrylate monomers may include alkyl (meth)acrylates. Examples of alkyl (meth)acrylates include linear or branched alkyl (meth)acrylates in which the alkyl group has 1 to 10 carbon atoms. Examples of the alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, n-octyl, isooctyl, n-nonyl, isonyl, n-decyl, isodecyl, etc.

[0121] Furthermore, examples of (meth)acrylate monomers include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, tert-pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, etc.

[0122] Furthermore, in this invention, the (meth)acrylate polymer may include one or more of poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, and poly(meth)acrylate.

[0123] In some embodiments, the mass ratio of monomer to linear polymer is 10 / 1 to 4 / 1, preferably 9 / 1 to 5 / 1, for example 8 / 1.

[0124] In some embodiments, the volume ratio of monomer to crosslinking agent is 40 / 1 to 5 / 1, preferably 20 / 1 to 10 / 1, for example 15 / 1.

[0125] In some embodiments, the mass ratio of monomer to initiator is 200 / 1 to 50 / 1, preferably 150 / 1 to 80 / 1, for example 100 / 1.

[0126] The initiator in this invention is a free radical initiator, such as one or more of azo initiators and peroxide initiators. Examples of azo initiators include, but are not limited to, azobisisobutyronitrile (AIBN) and azobisisoheptanenitrile (AIBN). Examples of peroxide initiators include, but are not limited to, benzoyl peroxide, dodecyl peroxide, N,N-dimethylaniline, tert-butyl hydroperoxide, tert-butyl peroxybenzoate, and tert-butyl pervalerate. Azo initiators are preferred, and azobisisobutyronitrile (AIBN) is most preferred.

[0127] The types of monomers and crosslinking agents that can be used in this invention are as described above. Preferably, the monomers comprise styrene-based monomers.

[0128] [Sub-step (P-3)]

[0129] In sub-step (P-3), a dispersion (suspension) in which the oil phase is dispersed in the aqueous phase is prepared.

[0130] In some implementations, the volume ratio of the aqueous phase to the oil phase is 5 / 1 to 3 / 1; for example, 4 / 1.

[0131] In some implementations, dispersion is carried out by high-speed stirring at a speed of 1000–3000 rpm.

[0132] In some embodiments, dispersion is carried out by ultrasonic treatment for a duration of, for example, 1 to 30 minutes, preferably 2 to 15 minutes.

[0133] [Sub-step (P-4)]

[0134] In sub-step (P-4), a free radical polymerization reaction of monomers and crosslinking agents is carried out to form a crosslinked polymer, resulting in polymer microspheres.

[0135] In some implementations, the polymerization temperature is 60–80°C, for example, 70°C.

[0136] In some embodiments, the polymerization reaction is carried out under stirring at a speed of 100–300 rpm, for example, 150 rpm.

[0137] In some implementations, the polymerization reaction time is 5 to 8 hours, preferably 6 to 7 hours.

[0138] [Sub-step (P-5)]

[0139] In sub-step (P-5), a monomer emulsion comprising a monomer having an alkoxysilane structure, an emulsifier, an initiator, and water is prepared.

[0140] The emulsifier in this invention is an oil-in-water emulsifier. Preferably, the emulsifier is selected from at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0141] The initiator in this invention is a water-soluble free radical initiator, including but not limited to sodium persulfate, potassium persulfate, ammonium persulfate, etc.

[0142] In some embodiments, the mass ratio of the monomer having the alkoxysilane structure to water is 1 / 20 to 1 / 5, for example, 1 / 10.

[0143] In some embodiments, the mass ratio of emulsifier to water is 1 / 1000 to 5 / 1000, preferably 2 / 1000.

[0144] In some embodiments, the mass ratio of initiator to water is 1 / 1000 to 5 / 1000, preferably 2 / 1000.

[0145] [Sub-step (P-6)]

[0146] In sub-step (P-6), a seed swelling polymerization reaction is carried out, in which the resulting polymer microspheres are dispersed in water as seeds, and a monomer emulsion is added dropwise. During the reaction, the original polymer separates from the polymer with an alkoxysilane structure, thereby forming microsphere portions and one or more protrusions on the surface of the microsphere portions, thus obtaining snowman-shaped Janus particles or patchy particles.

[0147] In some embodiments, the mass ratio of polymer microspheres to monomers with alkoxysilane structures in the monomer emulsion is 1 / 2 to 2 / 1.

[0148] On the one hand, the mass ratio of polymer microspheres to monomers with alkoxysilane structures in the monomer emulsion is 1 / 2 to 1 / 1, in which snowman-shaped Janus particles are obtained.

[0149] On the other hand, when the mass ratio of polymer microspheres to monomers with alkoxysilane structures in the monomer emulsion is 1 / 1 to 2 / 1, patchy particles are obtained.

[0150] In some implementations, the polymerization temperature is 60–80°C, for example, 70°C.

[0151] In some embodiments, the polymerization reaction is carried out under stirring at a speed of 100–300 rpm, for example, 150 rpm.

[0152] In some implementations, the reaction time is 5 to 8 hours, preferably 6 to 7 hours.

[0153] [Sub-step (P-7)]

[0154] In sub-step (P-7), the pH is adjusted to induce a sol-gel reaction in the alkoxysilane.

[0155] In some embodiments, the pH of the aqueous phase is 7–11, preferably 8–10, for example 8. The pH of the aqueous phase can be adjusted to this range using a pH adjuster. The pH adjuster is, for example, at least one selected from ammonia (NH3), sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate. By adjusting the pH of the aqueous phase to the level described above, the sol-gel reaction can proceed smoothly. Ammonia can be added to the aqueous phase to adjust the pH.

[0156] Hole Forming Steps

[0157] In the pore-forming step, the snowman-shaped Janus particles or patchy particles obtained in the polymerization step are brought into contact with a solvent, causing the linear polymer contained therein to dissolve into the solvent, thereby forming the through-hole.

[0158] The linear polymer is the linear polymer portion formed by the polymerization reaction between monomers during the reaction process of the oil-dissolved polymer and sub-step (P-4).

[0159] In some embodiments, the time for contacting the snowman-shaped Janus particles or patchy particles obtained in the polymerization step with the solvent is 1 to 8 hours, preferably 2 to 7 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, etc.

[0160] Preferably, the snowman-shaped Janus particles or patchy particles obtained in the polymerization step are immersed in a solvent, thereby dissolving the linear polymer in the solvent.

[0161] The solvent used in the pore-forming step is a good solvent for linear polymers, such as at least one selected from glacial acetic acid, acetone, ethylene glycol, and N,N-dimethylformamide.

[0162] Post-processing steps

[0163] The preparation method of the present invention may also optionally include a post-processing step, such as separating, washing and drying the obtained porous particles after the pore-forming step.

[0164] The present invention also relates to porous particles prepared by the method of the present invention.

[0165] <Application>

[0166] The present invention also relates to the use of the porous particles of the present invention in catalysts, oil-water emulsification, biomedicine, and wastewater treatment, such as in immobilized enzymes.

[0167] Example

[0168] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by this invention.

[0169] Unless otherwise specified, all percentages in the following examples are by mass percentages.

[0170] Example 1

[0171] Step 1: Preparation of snowman-shaped Janus granules:

[0172] 1 g of polymethyl methacrylate was dissolved in 9 ml of styrene, and 0.9 ml of divinylbenzene and 0.05 g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 1 g of polyvinyl alcohol was dissolved in 40 ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 min to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70 °C and stirring at 150 rpm for 6 h. The reaction solution was transferred to a centrifuge tube and centrifuged at 10,000 rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0173] 2 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain snowman-shaped Janus particles.

[0174] Step 2: Removal of linear polymers

[0175] Take 1g of the dried, snowman-shaped Janus granules, add 10ml of acetone, and sonicate for approximately 4 hours. Then transfer the mixture to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, a solid product is obtained. This solid product is repeatedly washed with acetone and then dried to obtain porous, snowman-shaped Janus granules with a particle size of 100–300μm, a pore size range of 20–100nm, a porosity of 15%, and a specific surface area of ​​5m². 2 / g.

[0176] Example 2

[0177] Step 1: Preparation of snowman-shaped Janus granules:

[0178] 2g of polymethyl methacrylate was dissolved in 8ml of styrene, and 0.8ml of divinylbenzene and 0.05g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 1g of polyvinyl alcohol was dissolved in 40ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 minutes to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70℃ and stirring at 150rpm for 6 hours. The reaction solution was transferred to a centrifuge tube and centrifuged at 10000rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0179] 2 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain snowman-shaped Janus particles.

[0180] Step 2: Removal of linear polymers

[0181] Take 1g of the dried, snowman-shaped Janus granules, add 10ml of acetone, and sonicate for approximately 4 hours. Then transfer the mixture to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, a solid product is obtained. This solid product is repeatedly washed with acetone and then dried to obtain porous, snowman-shaped Janus granules with a particle size of 100–300μm, a pore size range of 50–200nm, a porosity of 40%, and a specific surface area of ​​20m². 2 / g.

[0182] Example 3

[0183] Step 1: Preparation of patchy particles:

[0184] 1 g of polymethyl methacrylate was dissolved in 9 ml of styrene, and 0.9 ml of divinylbenzene and 0.05 g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 1 g of polyvinyl alcohol was dissolved in 40 ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 min to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70 °C and stirring at 150 rpm for 6 h. The reaction solution was transferred to a centrifuge tube and centrifuged at 10,000 rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0185] 1 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain patchy particles.

[0186] Step 2: Removal of linear polymers

[0187] Take 1g of the dried patchy particles, add 10ml of acetone, and sonicate for approximately 4 hours. Then transfer to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, a solid product is obtained. Wash thoroughly with acetone and dry to obtain porous patchy particles with a particle size of 100–300μm, a pore size range of 20–100nm, a porosity of 15%, and a specific surface area of ​​5m². 2 / g.

[0188] Example 4

[0189] Step 1: Preparation of snowman-shaped Janus granules:

[0190] 1 g of polymethyl methacrylate was dissolved in 9 ml of methylstyrene, and 0.9 ml of divinylbenzene and 0.05 g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 1 g of polyvinyl alcohol was dissolved in 40 ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 min to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70 °C and stirring at 150 rpm for 6 h. The reaction solution was transferred to a centrifuge tube and centrifuged at 10,000 rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0191] 2 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain snowman-shaped Janus particles.

[0192] Step 2: Removal of linear polymers

[0193] Take 1g of the dried, snowman-shaped Janus granules, add 10ml of acetone, and sonicate for approximately 4 hours. Then transfer the mixture to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, a solid product is obtained. This solid product is repeatedly washed with acetone and then dried to obtain porous, snowman-shaped Janus granules with a particle size of 100–300μm, a pore size range of 20–100nm, a porosity of 15%, and a specific surface area of ​​5m². 2 / g.

[0194] Example 5

[0195] Step 1: Preparation of snowman-shaped Janus granules:

[0196] 1 g of polymethyl methacrylate was dissolved in 9 ml of styrene, and 0.9 ml of divinylbenzene and 0.05 g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 2 g of polyvinyl alcohol was dissolved in 40 ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 min to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70 °C and stirring at 150 rpm for 6 h. The reaction solution was transferred to a centrifuge tube and centrifuged at 10,000 rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0197] 2 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain snowman-shaped Janus particles.

[0198] Step 2: Removal of linear polymers

[0199] Take 1g of the dried, snowman-shaped Janus granules, add 10ml of acetone, and sonicate for approximately 4 hours. Then transfer the mixture to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, obtain a solid product. Wash thoroughly with acetone and dry to obtain porous, snowman-shaped Janus granules with a particle size of 50–200μm, a pore size range of 20–100nm, a porosity of 15%, and a specific surface area of ​​5m². 2 / g.

[0200] Example 6

[0201] Step 1: Preparation of snowman-shaped Janus granules:

[0202] 1 g of polymethyl methacrylate was dissolved in 9 ml of styrene, and 0.9 ml of divinylbenzene and 0.05 g of azobisisobutyronitrile were added. After thorough dissolution, an oil phase was prepared. 1 g of polyvinyl alcohol was dissolved in 40 ml of water. After thorough dissolution, an aqueous phase was prepared. The aqueous and oil phases were mixed and subjected to ultrasonic vibration for 3 min to form a uniformly dispersed suspension of the oil phase in the aqueous phase. The oil-water mixture was transferred to a flask and subjected to free radical suspension polymerization under controlled temperature of 70 °C and stirring at 150 rpm for 6 h. The reaction solution was transferred to a centrifuge tube and centrifuged at 10,000 rpm. After centrifugation, a solid product was obtained, which was repeatedly washed with water and then freeze-dried to obtain polymer microspheres.

[0203] 2 g of 3-methacryloyloxypropyltrimethoxysilane, 0.02 g of potassium persulfate, 0.02 g of sodium dodecylbenzenesulfonate, and 10 mL of water were ultrasonically treated for 10 min to form a monomer emulsion. 1 g of dried polymer microspheres were dispersed in 20 mL of water, heated to 70 °C, and the monomer emulsion was added dropwise over 30 min. After polymerization for 6 h, ammonia was added to adjust the pH to 8, and stirring continued for 1 h to induce a sol-gel process. The solid product was repeatedly washed with water and ethanol, then freeze-dried to obtain snowman-shaped Janus particles.

[0204] Step 2: Removal of linear polymers

[0205] Take 1g of the dried, snowman-shaped Janus granules, add 10ml of glacial acetic acid, and sonicate for approximately 4 hours. Then transfer the mixture to a centrifuge tube and centrifuge at 10000rpm. After centrifugation, a solid product is obtained. This solid product is repeatedly washed with glacial acetic acid and then dried to obtain porous, snowman-shaped Janus granules with a particle size of 100–300μm, a pore size range of 20–100nm, a porosity of 10%, and a specific surface area of ​​3m². 2 / g.

[0206] Industrial availability

[0207] The preparation method of the present invention can be mass-produced, and the particle size and pore size can be controlled, which provides the possibility for the application of porous polymer composite snowman-shaped Janus and patchy particles in many fields such as oil-water emulsification, biomedicine, and wastewater treatment.

Claims

1. A porous particle, characterized in that, It has a through-hole, includes a microsphere portion and one or more protrusions located on the surface of the microsphere portion, wherein the microsphere portion comprises a cross-linked polymer and the protrusions comprise silicon oxide. The porous particles are snowman-shaped Janus particles or patchy particles. Each of the snowman-shaped Janus particles has a microsphere portion and a protrusion portion; each of the patchy particles has a microsphere portion and multiple protrusion portions.

2. The porous particles according to claim 1, characterized in that, The crosslinked polymer comprises structural units derived from monomers and structural units derived from crosslinking agents, wherein the monomers are at least one selected from styrene monomers and (meth)acrylate monomers, and the crosslinking agents are at least one selected from divinylbenzene crosslinking agents and (meth)acrylate crosslinking agents.

3. The porous particles according to claim 1, characterized in that, The porous particles have an average particle size of 50–300 μm; and / or, The porous particles have a pore size of 20–200 nm; and / or, The porosity of the porous particles is 10–50%; and / or, The specific surface area of ​​the porous particles is 1–50 m². 2 / g.

4. The porous particles according to claim 1, characterized in that, The protrusion is formed by polymerization and sol-gel reactions of monomers having an alkoxysilane structure, wherein the monomers having an alkoxysilane structure have (meth)acryloyloxy and alkoxysilyl groups.

5. The method for preparing porous particles according to any one of claims 1 to 4, characterized in that, Includes polymerization and pore-forming steps: The polymerization step includes the following sub-steps: (P-1) Dissolve the dispersant in water to obtain an aqueous phase; (P-2) A linear polymer, monomer, crosslinking agent and initiator are mixed to obtain an oil phase; (P-3) The aqueous phase and oil phase are mixed and dispersed to obtain a dispersion in which the oil phase is dispersed in the aqueous phase; (P-4) Under polymerization conditions, monomers and crosslinking agents undergo a polymerization reaction to obtain polymer microspheres; (P-5) A monomer having an alkoxysilane structure, an emulsifier, an initiator, and water are mixed to obtain a monomer emulsion; (P-6) The obtained polymer microspheres were dispersed in water and mixed with monomer emulsion under polymerization conditions to carry out seed swelling polymerization reaction, resulting in snowman-shaped Janus particles or patchy particles. (P-7) When a pH adjuster is added, the alkoxysilane undergoes a sol-gel reaction; The pore-forming step includes: contacting the snowman-shaped Janus particles or patchy particles obtained in the polymerization step with a solvent, so that the linear polymer contained therein dissolves into the solvent, thereby forming the through-hole.

6. The preparation method according to claim 5, characterized in that, In sub-step (P-1), the dispersant is at least one selected from polyvinyl alcohol, gelatin, starch, polyacrylic acid, and sulfonated polystyrene; the mass ratio of water to dispersant in the aqueous phase is 50 / 1 to 10 / 1; In sub-step (P-2), the mass ratio of monomer to linear polymer is 10 / 1 to 4 / 1; the volume ratio of monomer to crosslinking agent is 40 / 1 to 5 / 1; and the mass ratio of monomer to initiator is 200 / 1 to 50 / 1. In sub-step (P-3), the volume ratio of the aqueous phase to the oil phase is 5 / 1 to 3 / 1; In sub-step (P-5), the emulsifier is at least one selected from sodium dodecyl sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate; the initiator is at least one selected from sodium persulfate, potassium persulfate, and ammonium persulfate; the mass ratio of the monomer having an alkoxysilane structure to water is 1 / 20 to 1 / 5; the mass ratio of the emulsifier to water is 1 / 1000 to 5 / 1000; and the mass ratio of the initiator to water is 1 / 1000 to 5 / 1000. In sub-step (P-6), the mass ratio of polymer microspheres to monomers with alkoxysilane structures in the monomer emulsion is 1 / 2 to 2 / 1; In sub-step (P-7), the pH of the aqueous phase is 7 to 11, and the pH adjuster is at least one selected from ammonia (NH3), sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate.

7. The preparation method according to claim 5, characterized in that, In sub-step (P-4), the polymerization conditions include: polymerization temperature of 60-80℃, stirring speed of 100-300 rpm, and reaction time of 5-8h; in sub-step (P-6), the polymerization conditions include: polymerization temperature of 60-80℃, and reaction time of 5-8h.

8. The preparation method according to claim 5, characterized in that, The solvent used in the pore-forming step is at least one selected from glacial acetic acid, acetone, ethylene glycol, and N,N-dimethylformamide, and the contact time with the solvent is 1 to 8 hours.

9. Porous particles prepared by the method according to any one of claims 5 to 8.

10. The use of porous particles according to any one of claims 1 to 4 and 9 in catalysts, oil-water emulsification, biomedical applications, and wastewater treatment.

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