阅读说明：本技术 一种双亲性单链Janus复合纳米颗粒及其制备方法和应用 (Amphiphilic single-chain Janus composite nano-particle and preparation method and application thereof ) 是由 刘冰 杨丽萍 于 2020-04-28 设计创作，主要内容包括：本发明公开一种双亲性单链Janus复合纳米颗粒及其制备方法和应用。所述复合纳米颗粒包括亲油高分子单链-聚合物分子刷-亲水高分子单链、以及原位复合在所述聚合物分子刷上的无机纳米颗粒。利用阴离子活性聚合方法,依活性顺序依次加入亲油单体、大分子单体和亲水单体,分段聚合,得到中间为聚合物分子刷、端部分别为亲水链段和亲油链段结构的聚合物；对所述聚合物中的聚合物分子刷改性引入羧基,并原位复合生长无机纳米颗粒,得到该复合纳米颗粒。本发明实现了双亲性单链Janus复合纳米颗粒的大批量制备,结合复合材料和纳米材料的优异性能,在催化、药物控释、酶的固定、污染物处理等领域具有重要的意义。(The invention discloses an amphiphilic single-chain Janus composite nanoparticle and a preparation method and application thereof. The composite nano-particles comprise oleophylic macromolecule single chains, polymer molecule brushes, hydrophilic macromolecule single chains and inorganic nano-particles compounded on the polymer molecule brushes in situ. Sequentially adding lipophilic monomers, macromonomers and hydrophilic monomers according to an active sequence by using an anion active polymerization method, and carrying out sectional polymerization to obtain a polymer with a polymer molecular brush in the middle and hydrophilic chain segments and lipophilic chain segment structures at the end parts; and modifying the polymer molecular brush in the polymer, introducing carboxyl, and carrying out in-situ composite growth on inorganic nano particles to obtain the composite nano particles. The invention realizes the mass preparation of the amphiphilic single-chain Janus composite nano-particles, combines the excellent properties of the composite material and the nano-material, and has important significance in the fields of catalysis, drug controlled release, enzyme immobilization, pollutant treatment and the like.)

1. An amphiphilic single-chain Janus composite nanoparticle is characterized in that the composite nanoparticle comprises an oleophylic high-molecular single chain, a polymer molecular brush, a hydrophilic high-molecular single chain and an inorganic nanoparticle compounded on the polymer molecular brush in situ.

2. The composite nanoparticle of claim 1, wherein the inorganic nanoparticle is in-situ growth complexed via the carboxyl-modified ends of the polymer molecular brush. Preferably, the carboxyl modified end of the polymer molecular brush introduces carboxyl to the polymer molecular brush through thiol-double bond click reaction.

Preferably, the lipophilic macromolecule single chain is positioned at one end of the polymer molecular brush, and the hydrophilic macromolecule single chain is positioned at the other end of the polymer molecular brush. Preferably, the number of the hydrophilic macromolecule single chains and the number of the lipophilic macromolecule single chains are both one.

Preferably, the polymer molecular brush is obtained by introducing a macromonomer at the end of the lipophilic macromolecule single chain and polymerizing.

Preferably, the macromonomer is polymerized from monomer X and monomer Y. Preferably, the monomer X is selected from anionically active polymerized monomers, for example at least one selected from 4- (vinylphenyl) -1-butene, isoprene, 1, 2-polybutadiene.

Preferably, the monomer Y is selected from at least one of 4- (chlorodimethylsilyl) styrene and 4-chloromethyl styrene.

3. The composite nanoparticle according to claim 1 or 2, wherein the hydrophilic polymer single-chain polymerized monomer is at least one of 2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester, oligoethyleneglycolmethylether methacrylate, ethyleneglycol methylether acrylate, N-dimethylacrylamide, N-diethylacrylamide, N-ethylmethacrylamide, N-methacryl-N '-methylpiperazine, N-acryl-N' -methylpiperazine, dimethylaminoethyl methacrylate, glycidyl methacrylate, ethylene oxide, propylene oxide, and butylene oxide.

Preferably, the lipophilic macromolecule single-chain polymerization monomer is a styrene monomer, such as at least one of styrene, p-methylstyrene and alpha-methylstyrene.

Preferably, the degree of polymerization of the hydrophilic polymer single chain is 30 to 1000.

Preferably, the degree of polymerization of the lipophilic macromolecule single chain is 30-1000.

Preferably, the degree of polymerization of the polymer molecular brush is 5 to 500.

Preferably, the inorganic nanoparticles are selected from at least one of metal, metal compound and non-metal compound nanoparticles.

Preferably, the metal is selected from at least one of Au, Ag, Pt, Pd, Fe, Co, Ni, Sn, In, and alloys thereof.

Preferably, the metal compound is selected from Fe₃O₄、TiO₂、Al₂O₃、BaTiO₃、SrTiO₃At least one of CdS, ZnS, PbS, CdTe and CdSe.

Preferably, the non-metallic compound is SiO₂。

Preferably, the inorganic nanoparticles have an average particle size of 5 to 30 nm.

4. The composite nanoparticle according to any one of claims 1 to 3, wherein the amphiphilic single-chain Janus composite nanoparticle is a polystyrene-ferroferric oxide-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-gold-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-nickel-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-ferroferric oxide-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle Particles or polystyrene-ferroferric oxide-polyglycidyl methacrylate Janus composite nano particles.

5. The method for preparing amphiphilic single-chain Janus composite nanoparticles as claimed in any one of claims 1 to 4, which is characterized by comprising the following steps: sequentially adding lipophilic monomers, macromonomers and hydrophilic monomers according to the active sequence by using an anion active polymerization method, and carrying out sectional polymerization to obtain a polymer with a polymer molecular brush in the middle, wherein one end of the polymer molecular brush is a hydrophilic chain segment, and the other end of the polymer molecular brush is a lipophilic chain segment structure; and modifying a polymer molecular brush in the polymer, introducing carboxyl, and carrying out in-situ composite growth on inorganic nanoparticles to obtain the amphiphilic single-chain Janus composite nanoparticles.

Preferably, the lipophilic monomer has the same meaning as the polymerized monomer of the lipophilic single-chain polymer according to any one of claims 1 to 4, the hydrophilic monomer has the same meaning as the polymerized monomer of the hydrophilic single-chain polymer according to any one of claims 1 to 4, the macromonomer has the meaning according to claim 2, and the inorganic nanoparticle has the meaning according to claim 3.

6. The method of manufacturing according to claim 5, comprising the steps of:

step 1), under the action of an initiator, carrying out anion active polymerization on a monomer X, and adding a monomer Y to terminate anion active species to obtain a macromonomer;

step 2), under the action of an initiator, carrying out anion active polymerization reaction on a polymerized monomer of the oleophylic high-molecular single chain to obtain the oleophylic high-molecular single chain;

step 3), adding the macromonomer obtained in the step 1) into the reaction system obtained in the step 2), and continuously initiating the end of the oleophylic macromolecule single chain to generate a polymer molecular brush;

step 4), adding a hydrophilic polymer single-chain polymerization monomer into the reaction system in the step 3), and continuously initiating the tail end of the polymer molecular brush to generate a hydrophilic polymer single-chain to obtain a polymer with a middle polymer molecular brush, wherein one end of the polymer is a hydrophilic chain segment, and the other end of the polymer is a lipophilic chain segment structure, and the polymer is marked as a polymer C with a lipophilic chain-polymer molecular brush-hydrophilic chain composite structure;

and 5) modifying the polymer molecular brush in the polymer C, introducing carboxyl, and carrying out in-situ composite growth on inorganic nanoparticles to obtain the amphiphilic single-chain Janus composite nanoparticles.

7. The method according to claim 6, wherein in the step 1), the concentration of the monomer X in the reaction system of the anionic living polymerization reaction is 1 to 40 wt%;

preferably, the molar ratio of the monomer Y to the initiator is 1-10: 1;

preferably, the molar ratio of the monomer X to the initiator is 10-50: 1;

preferably, the number average molecular weight of the macromonomer is (2-12). times.10³。

Preferably, in the step 2), the concentration of the lipophilic macromolecule single chain polymerization monomer in the anion living polymerization reaction system is 0.5-3 wt%;

the number average molecular weight of the oleophylic macromolecule single chain is (2-6) multiplied by 10³。

Preferably, the temperature of the anionic living polymerization reaction in the steps 1), 2) and 3) is-85 to-70 ℃; preferably, the time of the anionic living polymerization reaction is 10 to 30 min.

8. The method according to claim 6 or 7, wherein in step 3), the concentration of the macromonomer in the anionic living polymerization reaction system is 5 to 20 wt%;

preferably, the number average molecular weight of the polymer molecular brush is (40-110). times.10³；

Preferably, the concentration of the polymerized monomer of the hydrophilic high molecular single chain in the anion living polymerization reaction system is 0.5-3 wt%;

preferably, the reaction temperature in the step 4) is the same as that in the reaction system in the step 3), and the reaction time is 1-4 h;

preferably, the polymer C has a number average molecular weight of (60-120). times.10³。

9. The method according to any one of claims 6 to 8, wherein in step 5) the modification is the introduction of carboxyl groups into the side chains of the polymer brush by means of a thiol-double bond click reaction.

Preferably, the mercapto compound used in the mercapto-double bond click reaction may be selected from thioglycolic acid and/or mercaptopropionic acid.

Preferably, the mercapto-double bond click reaction is carried out under an initiator, for example a photoinitiator, such as 2, 2-dimethoxy-2-phenylacetophenone.

Preferably, the molar ratio of the mercapto compound to the double bonds contained in polymer C is 1-2: 1.

Preferably, the initiator is present in a molar ratio of 1 to 5% relative to the double bonds of the polymer C.

Preferably, the thiol-double bond click reaction is initiated under ultraviolet illumination.

Preferably, the temperature of the thiol-double bond click reaction is 15-40 ℃.

Preferably, the time of the thiol-double bond click reaction is 2-6 h.

Preferably, the reaction system of steps 1) -5) further comprises a reaction solvent.

10. Use of the amphiphilic single-chain Janus composite nanoparticle of any one of claims 1-4 in the fields of catalysis, controlled drug release, enzyme immobilization, and product separation or contaminant treatment.

Technical Field

The invention belongs to the technical field of inorganic, organic and high polymer materials, and particularly relates to an amphiphilic single-chain Janus composite nanoparticle and a preparation method and application thereof.

Background

The Single-Chain Janus composite nano-particles integrate Polymer performance and nano-particle function, and especially tadpole-shaped asymmetric nano-particles taking functional solid nano-particles as heads and Single-Chain polymers as tails attract attention (J.A. Pomposo, Single-Chain Polymer Nanoparticles: Synthesis, Characterisation, Simulation, and applications.first edition; Wiley-VCH: Weinheim, 2017). The properties can be widely adjusted by selecting different nanoparticles and polymer chains. There is an urgent need for precise design of single-chain Janus composite nanoparticles and development of new methods for their batch preparation. Currently, intramolecular cross-linking of macromolecules, especially block macromolecules, is a common method for preparing such composite nanoparticles (s.mavila, o.eivgi, i.berkovich, n.g.lemcof, chem.rev.2016,116, 878-961). However, this method needs to be carried out in a very dilute polymer solution, otherwise intermolecular crosslinking occurs to cause a gel phenomenon. Recently, we propose a new method of intramolecular cross-linking based on electrostatic regulation to achieve the preparation of single-chain nanoparticles in concentrated solution (d.xiang, x.chen, l.tang, b.y.jiang, z.z.yang, CCS chem.2019,1, 407-430). In order to generate functionality, the nanoparticles are required to be further compositely grown as microreactors. The method has complicated steps, and relates to a multi-step separation process, so that the preparation efficiency is low. In addition, the choice of block polymer structures and compositions is limited, limiting the microstructural design of single-chain Janus composite nanoparticles. Both of these aspects severely limit the wide engineering applications of such materials. Therefore, the design of a novel structure of the single-chain Janus composite nanoparticle and a low-cost and efficient preparation method thereof are problems to be solved at present.

Disclosure of Invention

The invention provides an amphiphilic single-chain Janus composite nanoparticle which comprises an oleophylic high-molecular single chain, a polymer molecular brush, a hydrophilic high-molecular single chain and an inorganic nanoparticle compounded on the polymer molecular brush in situ.

Preferably, the inorganic nanoparticles are growth-complexed in situ through the carboxyl modified ends of the polymer molecular brush. Preferably, the carboxyl modified end of the polymer molecular brush can introduce carboxyl to the polymer molecular brush through thiol-double bond click reaction.

According to an embodiment of the present invention, the lipophilic single-chain polymer is located at one end of the polymer molecular brush, and the hydrophilic single-chain polymer is located at the other end of the polymer molecular brush. Preferably, the number of the hydrophilic macromolecule single chains and the number of the lipophilic macromolecule single chains are both one.

According to an embodiment of the present invention, the polymer molecular brush is obtained by introducing a macromonomer into the single-chain end of the lipophilic macromolecule for polymerization.

Preferably, the macromonomer is polymerized from monomer X and monomer Y. For example, the monomer X may be selected from anionic living polymerization monomers, such as at least one selected from 4- (vinylphenyl) -1-butene, isoprene, butadiene and the like. For example, the monomer Y is at least one selected from 4- (chlorodimethylsilyl) styrene, 4-chloromethylstyrene and the like.

According to an embodiment of the present invention, the polymerized monomer of the hydrophilic polymer single chain may be at least one of 2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester, oligoethyleneglycolmethylether methacrylate, ethyleneglycol methylether acrylate, N-dimethylacrylamide, N-diethylacrylamide, N-ethylmethacrylamide, N-methacryloyl-N '-methylpiperazine, N-acryloyl-N' -methylpiperazine, dimethylaminoethyl methacrylate, glycidyl methacrylate, ethylene oxide, propylene oxide, butylene oxide, and the like; 2- (2-methoxyethoxy) ethyl 2-methyl-2-acrylate, dimethylaminoethyl methacrylate or glycidyl methacrylate are preferred.

According to an embodiment of the present invention, the lipophilic polymeric single chain monomer may be a styrenic monomer, such as at least one of styrene, p-methylstyrene, α -methylstyrene, and the like, illustratively styrene.

According to an embodiment of the present invention, the degree of polymerization of the hydrophilic polymer single chain is 30 to 1000, such as 35 to 500, further such as 40 to 200, exemplary 35, 50, 80, 100, 120, 150.

According to an embodiment of the invention, the degree of polymerization of said lipophilic polymeric single chains is in the range of 30 to 1000, such as 35 to 500, further such as 40 to 200, exemplary 40, 46, 60, 100.

According to an embodiment of the invention, the degree of polymerization of the polymer molecular brush is in the range of 5 to 500, such as 8 to 200, further such as 10 to 150, exemplary 10, 25, 50, 100.

According to an embodiment of the present invention, the inorganic nanoparticles may be selected from at least one of metal, metal compound and non-metal compound nanoparticles.

For example, the metal may be selected from at least one of Au, Ag, Pt, Pd, Fe, Co, Ni, Sn, In, and alloys thereof; preferably Au, Ni, Pd, Fe or Co.

For example, the metal compound may be selected from Fe₃O₄、TiO₂、Al₂O₃、BaTiO₃、SrTiO₃At least one of CdS, ZnS, PbS, CdTe and CdSe; preferably Fe₃O₄、TiO₂Or Al₂O₃。

For example, the non-metallic compound is SiO₂。

According to an embodiment of the invention, the inorganic nanoparticles have an average particle size of 5-30nm, such as 10-25nm, exemplary 10nm, 15nm, 20 nm.

According to an exemplary embodiment of the present invention, the amphiphilic single-chain Janus composite nanoparticle may be a polystyrene-ferroferric oxide-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-gold-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-nickel-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, a polystyrene-ferroferric oxide-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticle, or a polystyrene-ferroferric oxide-poly (ethylene glycol-ethylene glycol ether) Glycidyl methacrylate Janus composite nanoparticles.

The invention also provides a preparation method of the amphiphilic single-chain Janus composite nano-particle, which comprises the following steps: sequentially adding lipophilic monomers, macromonomers and hydrophilic monomers according to the active sequence by using an anion active polymerization method, and carrying out sectional polymerization to obtain a polymer with a polymer molecular brush in the middle, wherein one end of the polymer molecular brush is a hydrophilic chain segment, and the other end of the polymer molecular brush is a lipophilic chain segment structure; and modifying a polymer molecular brush in the polymer, introducing carboxyl, and carrying out in-situ composite growth on inorganic nanoparticles to obtain the amphiphilic single-chain Janus composite nanoparticles.

Preferably, the lipophilic monomer has the same meaning as the above-mentioned polymeric monomer of the lipophilic macromolecule single chain. The hydrophilic monomer has the same meaning as the hydrophilic polymer single-chain polymerized monomer. The macromer and inorganic nanoparticles have the meanings as described above.

According to an embodiment of the invention, the preparation method comprises the following steps:

step 1), under the action of an initiator, carrying out anion active polymerization on a monomer X, and adding a monomer Y to terminate anion active species to obtain a macromonomer;

the monomer X and the monomer Y have the meanings as described above;

step 2), under the action of an initiator, carrying out anion active polymerization reaction on a polymerized monomer of the oleophylic high-molecular single chain to obtain the oleophylic high-molecular single chain;

step 3), adding the macromonomer obtained in the step 1) into the reaction system obtained in the step 2), and continuously initiating the end of the oleophylic macromolecule single chain to generate a polymer molecular brush;

step 4), adding a hydrophilic polymer single-chain polymerization monomer into the reaction system in the step 3), and continuously initiating the tail end of the polymer molecular brush to generate a hydrophilic polymer single-chain to obtain a polymer with a middle polymer molecular brush, wherein one end of the polymer is a hydrophilic chain segment, and the other end of the polymer is a lipophilic chain segment structure, and the polymer is marked as a polymer C with a lipophilic chain-polymer molecular brush-hydrophilic chain composite structure;

and 5) modifying the polymer molecular brush in the polymer C, introducing carboxyl, and carrying out in-situ composite growth on inorganic nanoparticles to obtain the amphiphilic single-chain Janus composite nanoparticles.

According to an embodiment of the present invention, in step 1) and/or step 2), the initiator is at least one of n-butyllithium, t-butyllithium, and the like.

According to an embodiment of the present invention, in step 1), the concentration of the monomer X in the reaction system of the anionic living polymerization reaction is 1 to 40 wt%, preferably 10 to 20 wt%, and exemplary 10 wt%, 15 wt%, 20 wt%, 30 wt%.

According to an embodiment of the present invention, in step 1), the molar ratio of initiator to monomer depends on the degree of polymerization of the macromonomer, as will be appreciated by those skilled in the art. For example, the monomer X to initiator molar ratio is 10 to 50:1, such as 20 to 40:1, exemplary 20:1, 25:1, 30:1, 35:1, 40: 1. The monomer Y is a polymerization terminator, and the molar ratio of the monomer Y to the initiator is 1-10: 1.

According to an embodiment of the invention, the temperature of the anionic living polymerization reaction in step 1) is between-85 and-70 ℃, such as between-80 and-75 ℃, exemplary at-78 ℃.

Wherein the anionic living polymerization reaction time is 10-30min, such as 15-25min, exemplary 20 min.

Wherein the anionic living polymerization reaction is carried out under the condition of vigorous stirring, for example, the stirring speed is 400-600rpm, preferably 500 rpm.

According to an embodiment of the present invention, in step 1), the anionic living polymerization reaction solution is added dropwise to the monomer Y under stirring.

According to an embodiment of the present invention, in step 1), the number average molecular weight of the macromonomer is (2-12). times.10³E.g. (3-10). times.10³Exemplary is 3 × 10³，3.1×10³，5×10³，6×10³，7×10³，7.8×10³g/mol，8×10³，9×10³，10×10³。

According to an embodiment of the invention, in step 1), the DLS size of the macromer in tetrahydrofuran solvent is 1-8nm, such as 2-6nm, exemplary 2nm, 3nm, 4nm, 5nm, 6 nm.

According to an embodiment of the invention, the temperature of the anionic living polymerization reaction in step 2) is in the range of-85 to-70 ℃, such as-80 to-75 ℃, exemplary-78 ℃.

Wherein the anionic living polymerization reaction time is 10-30min, such as 15-25min, exemplary 20 min.

According to an embodiment of the present invention, in step 2), the concentration of the polymerized monomer of the lipophilic macromolecule single chain in the anionic living polymerization reaction system is 0.5-3 wt%, such as 0.8-2 wt%, exemplarily 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%.

According to an embodiment of the present invention, in step 2), the number average molecular weight of the lipophilic polymer single chain is (2-6) × 10³E.g. (3-5). times.10³Exemplary is 3 × 10³，4×10³，4.8×10³，5×10³，6×10³。

According to an embodiment of the invention, in step 2), the DLS size of the lipophilic polymeric single chain in tetrahydrofuran solvent is 1-5nm, such as 2-4nm, exemplary 2nm, 3nm, 4 nm.

According to an embodiment of the invention, in step 3), the concentration of the macromonomer in the anionic living polymerization system is 5 to 20 wt%, for example 10 to 15 wt%, illustratively 10 wt%, 12 wt%, 15 wt%.

According to an embodiment of the present invention, in step 3), the temperature of the reaction is the same as the temperature of the reaction system in step 2). Wherein the reaction time is 10-30min, such as 15-25min, exemplary 20 min.

According to an embodiment of the present invention, in step 3), the number average molecular weight of the polymer molecular brush is (40 to 110) × 10³E.g. (60-100). times.10³Exemplary is 60 × 10³，70×10³，78.2×10³，80×10³，90×10³，95×10³，95.2×10³。

According to an embodiment of the invention, in step 3), the DLS size of the polymer molecular brush in tetrahydrofuran solvent is 7-15nm, such as 8-12nm, exemplary 8nm, 9nm, 10nm, 11nm, 12nm, 13 nm.

According to an embodiment of the present invention, in step 4), the concentration of the polymerized monomer of the hydrophilic polymer single chain in the anionic living polymerization reaction system is 0.5 to 3 wt%, for example, 0.8 to 2 wt%, illustratively 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%.

According to an embodiment of the present invention, when the polymerized monomer of the hydrophilic polymer single strand is selected from oligoethylene glycol methyl ether methacrylate in step 4), the average molecular weight of the oligoethylene glycol methyl ether methacrylate may be selected from 200-5000, such as 300, 475, 950 or 4000.

When the hydrophilic polymeric single-chain monomer is selected from polyethylene glycol methyl ether acrylate, the average molecular weight of the polyethylene glycol methyl ether acrylate may be selected from 400-40000, such as 480, 1000, 2000, 4000, 5000, 10000, 20000 or 30000.

According to an embodiment of the present invention, in step 4), the temperature of the reaction is the same as the temperature of the reaction system in step 3). Wherein the reaction time is 1-4h, such as 1.5-3h, exemplary 2 h.

According to an embodiment of the present invention, in step 4), the number average molecular weight of the polymer C is (60 to 120) × 10³E.g., (80-110). times.10³Exemplary is 80 × 10³，84.7×10³，85×10³，90×10³，100×10³。

According to an embodiment of the invention, in step 4), the polymer C brush has a DLS size in tetrahydrofuran solvent of 7-18nm, such as 10-15nm, exemplary 10nm, 13nm, 15 nm.

According to an embodiment of the present invention, in step 5), the modification is to introduce carboxyl groups to the side chains of the polymer brush by using a thiol-double bond click reaction.

Preferably, the mercapto compound used in the mercapto-double bond click reaction may be selected from thioglycolic acid and/or mercaptopropionic acid.

Preferably, the mercapto-double bond click reaction is carried out under an initiator, for example a photoinitiator, such as 2, 2-dimethoxy-2-phenylacetophenone.

Preferably, the mercapto compound and the double bonds of polymer C are present in a molar ratio of 1-2:1, illustratively 1.2: 1.

Preferably, the initiator is present in a molar ratio of 1 to 5%, exemplarily 2%, of the double bonds present in the polymer C.

Preferably, the thiol-double bond click reaction is initiated under ultraviolet illumination.

Preferably, the temperature of the thiol-double bond click reaction is 15-40 ℃, such as 20-35 ℃, exemplary 25 ℃, 30 ℃.

Preferably, the thiol-double bond click reaction is carried out for a time of 2 to 6h, such as 3 to 5h, exemplary 3h, 4h, 5 h.

According to an embodiment of the present invention, in step 5), the in-situ growth of the inorganic nanoparticles may be performed using a method known in the art.

According to an embodiment of the present invention, the reaction system of steps 1) to 5) further comprises a reaction solvent, for example, the reaction solvent is an organic solvent, preferably at least one of Tetrahydrofuran (THF), N-Dimethylformamide (DMF).

According to an embodiment of the present invention, the preparation method of the amphiphilic single-chain Janus composite nanoparticle comprises the following steps:

step 1), under the action of an initiator, carrying out anion active polymerization on 4- (vinyl phenyl) -1-butene, and adding 4- (chlorodimethylsilyl) styrene to terminate anion active species to obtain a macromonomer;

step 2), under the action of an initiator, carrying out anion active polymerization reaction on a polymerized monomer of the oleophylic high-molecular single chain to obtain the oleophylic high-molecular single chain;

step 3), adding the macromonomer obtained in the step 1) into the reaction system obtained in the step 2), and continuously initiating the end of the oleophylic macromolecule single chain to generate a polymer molecular brush;

step 4), adding a hydrophilic polymer single-chain polymerization monomer into the reaction system in the step 3), and continuously initiating the tail end of the polymer molecular brush to generate a hydrophilic polymer single-chain to obtain a polymer with a middle polymer molecular brush, wherein one end of the polymer is a hydrophilic chain segment, and the other end of the polymer is a lipophilic chain segment structure, and the polymer is marked as a polymer C with a lipophilic chain-polymer molecular brush-hydrophilic chain composite structure;

and 5) modifying the polymer molecular brush in the polymer C by using a sulfydryl-double bond click reaction to introduce carboxyl, and carrying out in-situ composite growth on inorganic nanoparticles to obtain the amphiphilic single-chain Janus composite nanoparticles.

The invention also provides the amphiphilic single-chain Janus composite nano-particle prepared by the method.

The invention also provides application of the amphiphilic single-chain Janus composite nano-particle in the fields of catalysis, drug controlled release, enzyme immobilization, product separation, pollutant treatment and the like.

The invention has the beneficial effects that:

the invention provides an amphiphilic single-chain Janus composite nanoparticle and a preparation method thereof, which realize the mass preparation of the amphiphilic single-chain Janus composite nanoparticle, combine the excellent performances of oleophylic and hydrophilic macromolecule single chains and a nano material to ensure that the composite material has high performance, and the composite nanoparticle has important application value in the fields of catalysis, drug controlled release, enzyme fixation, product separation, pollutant treatment and the like.

Drawings

Fig. 1 is a TEM topography of the composite nanoparticle prepared in example 2.

Fig. 2 is a TEM topography of the composite nanoparticle prepared in example 4.

Fig. 3 is a schematic diagram of the preparation of composite nanoparticles of example 1.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

Example 1 polystyrene-ferroferric oxide-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles

1) 10mL of THF and 1mL of n-BuLi were added in this order, and 1mL of VSt monomer was added at-78 ℃ with vigorous stirring at 500rpm, and the reaction was carried out for 20 min. Dropwise adding an anionic active species into the VSt monomer polymerization system under stirring: 1mL CDMSS monomer and 1mL THF mixture. And purifying the crude product obtained by polymerization in absolute ethyl alcohol for 3 times, and drying in vacuum to obtain the macromonomer. The number average molecular weight of the macromer was 7.8k, and the DLS size was 3nm (tetrahydrofuran as solvent).

2) 10mL of THF and 0.1mL of styrene are sequentially added, 6.7 mu L of initiator n-BuLi (0.01mmol) is added at the temperature of minus 78 ℃, and the reaction is carried out for 20min, thus obtaining the polystyrene, namely the lipophilic macromolecule single chain. Polystyrene has a number average molecular weight of 4.8k, a DLS size of 2nm (tetrahydrofuran as solvent), and the degree of polymerization of the oleophilic polymer single chain is 46.

3) Adding 1g of the macromolecular monomer into the system obtained in the step 2), reacting for 20min, and continuously initiating at the tail end of the oleophylic macromolecular single chain to generate the polymer molecular brush. The number average molecular weight of the polymer molecular brush was 78.2k, the DLS size was 11nm (tetrahydrofuran as solvent), and the degree of polymerization of the polymer molecular brush was 10.

4) To the system of step 3) was added 0.1mL of 2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester (MEO)₂MA) reacting for 2h, and continuously initiating to generate a hydrophilic macromolecule single chain at the tail end of the polymer molecular brush to obtain a polymer C with a lipophilic chain-polymer molecular brush-hydrophilic chain composite structure. The molecular weight of the polymer C is 84.7k, the DLS size is 13nm (tetrahydrofuran), and the polymerization degree of the hydrophilic macromolecule single chain is 35.

5) 2, 2-dimethoxy-2-phenylacetophenone is taken as a photoinitiator, and the 3-mercaptopropionic acid and the double bonds of the polymer molecular brush side chains of the polymer C are subjected to click reaction:

adding 5mL of N, N-dimethylformamide, 50 mu L of 3-mercaptoacetic acid and 3mg of 2, 2-dimethoxy-2-phenylacetophenone into a single-mouth bottle in sequence, introducing nitrogen for 30min to remove oxygen, initiating a reaction under the irradiation of a 365nm ultraviolet lamp, slowly dropwise adding a 1mL of solution of 100mg of polymer C (containing 0.57mmol of double bonds) and reacting at room temperature for 4 h. The crude product was purified 3 times in anhydrous ethanol and dried under vacuum to obtain a carboxyl group-introduced polymer.

0.3g of the polymer having carboxyl groups introduced therein was dissolved in 300mL of N, N-dimethylformamide, stirred at room temperature and purged with nitrogen for 1 hour. 87.6mg of ferrous sulfate heptahydrate and 170.1mg of ferric chloride hexahydrate in a molar ratio of 1:2 are added into the reaction system, and the mixture is stirred for 5 hours at room temperature under the protection of nitrogen. And then heating the reaction to 83 ℃ by using an oil bath, adding 26.25mL of ammonia water into the reaction system in batches, and rapidly stirring for about 1h to obtain the polystyrene-ferroferric oxide-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nano particles.

The preparation process of this example is shown in FIG. 3. The structure with a plurality of branched chains is a polymer molecular brush, one end of the polymer molecular brush is connected with a lipophilic single chain, and the other end of the polymer molecular brush is connected with a hydrophilic single chain. Ferroferric oxide is compounded on the polymer molecular brush in situ.

Example 2 polystyrene-gold-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles

Steps 1) -4) were the same as in example 1. The carboxyl group-introduced polymer (10mg) obtained in step 5) of example 1 was dissolved in 10mL of DMF, and HAuCl was added₄·3H₂O, COOH and HAuCl in a polymer having carboxyl groups introduced therein₄·3H₂The molar ratio of O is 1: 10. The mixture was stirred at room temperature overnight to allow the gold chlorate ions to be adsorbed sufficiently to COOH. And dialyzing the mixture with water to remove unadsorbed gold chlorate ions, dissolving the mixture in DMF again after freeze-drying, and reducing the mixture for 12 hours under the irradiation of an ultraviolet lamp with the wavelength of 303nm to obtain the polystyrene-gold-poly (2-methyl-2-acrylic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles.

TEM shows the existence of about 10nm nano particles, and proves that the polymer molecular brush is partially made of the successfully-compounded alloy nano particles (see figure 1).

Example 3 polystyrene-Nickel-Poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles

Steps 1) -4) were the same as in example 1. The carboxyl group-introduced polymer (2mg) obtained in step 5) in example 1 was dissolved in 4.0mL of DMF, and nickel nitrate (Ni (NO) was added₃)₂·6H₂O) in DMF (0.01mL, 50.0mg/mL), stirred overnight at room temperature to allow Ni to settle²⁺Sufficiently adsorb to the micro-regions where the nanoparticles are cross-linked. Dialysis to remove free Ni (NO)₃)₂Thereafter, the polymer was redispersed in DMF and NaBH was added₄In DMF (100. mu.L, 5.0mg/mL), and reduced at room temperature for 24 h. The product was collected with a magnet and washed with water several times to give polystyrene-nickel-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles.

Example 4 polystyrene-ferroferric oxide-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles

1) 10mL of THF and 2mL of n-BuLi were added in this order, and 1mL of VSt monomer was added at-78 ℃ with vigorous stirring at 500rpm, and the reaction was carried out for 20 min. Dropwise adding an anionic active species into the VSt monomer polymerization system under stirring: a mixture of 2mL CDMSS monomer and 2mL THF. And purifying the crude product obtained by polymerization in absolute ethyl alcohol for 3 times, and drying in vacuum to obtain the macromonomer. The number average molecular weight of the macromer was 3.1k, and the DLS size was 2nm (tetrahydrofuran as solvent).

Subsequent steps were performed in the same manner as in steps 2) to 5) of example 1 to obtain polystyrene-ferroferric oxide-poly (2-methyl-2-propenoic acid-2- (2-methoxyethoxy) ethyl ester) Janus composite nanoparticles. Transmission Electron Microscope (TEM) shows that about 15nm of nano particles exist, and proves that the polymer molecular brush part successfully compounds Fe₃O₄(see FIG. 2).

Example 5 polystyrene-ferroferric oxide-polyglycidyl methacrylate Janus composite nanoparticles

A polystyrene-polymer molecular brush was obtained in the same manner as in steps 1) to 3) of example 1.

In the step 4), 0.1mL of glycidyl methacrylate is added into the reaction system in the step 3) and reacted for 2h to obtain a polymer C. The number average molecular weight of the polymer C was 95.2k, the DLS size was 13nm (tetrahydrofuran as a solvent), and the degree of polymerization of the hydrophilic polymer single chain was 120.

The subsequent steps are to prepare the polystyrene-ferroferric oxide-polyglycidyl methacrylate Janus composite nano particles by the same method as the step 5) in the embodiment 1.

Particularly, the invention belongs to the pioneering invention, and the amphiphilic single-chain Janus composite nanoparticles which are most easily applied to the industry are exemplarily described in the examples, but from the mechanism and illustration described in the description of the invention, those skilled in the art can foresee that the inventive idea can be easily applied to the preparation of other amphiphilic single-chain Janus composite nanoparticles, and the application of the prepared amphiphilic single-chain Janus composite nanoparticles to the fields of catalysis, drug controlled release, enzyme immobilization and product separation, pollutant treatment, and the like.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.