CN101716482A - Polymer/precious metal nanoparticle hybrid hollow intelligent microsphere and preparation method thereof - Google Patents

Abstract

The invention relates to a polymer/noble metal nanoparticle hybrid hollow smart microsphere and a preparation method thereof. The composition and weight percentage of the polymer/noble metal nano particle hybrid hollow microsphere are as follows: 0.001%-0.01% of the noble metal nano particle; 99.99%-99.999% of the polymer. The polymer/precious metal nanoparticle hybrid hollow smart microspheres prepared by the present invention show that the hybrid hollow smart microspheres have higher catalytic activity at room temperature through the catalytic reduction test of p-nitrophenol, and their catalytic activity You can adjust. The hybrid hollow smart microspheres prepared by the invention have novel structural features and adjustable properties, and are expected to be widely used in high-efficiency and selective catalysis, biomedicine and other fields.

Description

A polymer/noble metal nanoparticle hybrid hollow smart microsphere and its preparation method

technical field

The invention belongs to the field of polymer science and technology, in particular to a polymer/noble metal nanoparticle hybrid intelligent hollow microsphere and a preparation method thereof.

Background technique

Noble metal nanoparticles have unique stability related to size, small size effect, quantum effect, surface effect and biological affinity, etc. As a good classical nanomaterial, it is a research hotspot in optics, electronics, catalysis and biomedicine. Ideal noble metal nanomaterials or composites require noble metal nanoparticles with limited size and shape, modified organic and/or biomolecules on the surface, special composite structures (such as core-shell structure) and the ability to transform in 2-D or 3D. Ordered arrangements in -D space or devices, which often have different properties than individual particles and macroscopic entities. Therefore, it is a research trend in this field to synthesize noble metal nanoparticle carriers with special structures and develop functional optical, electrical and biomedical materials (Daniel MC, Astruc D, Chem. Rev.; 2004, 104, 293).

As a special structural material, hollow spheres have attracted great attention in recent years, because the special hollow structure makes them exhibit a variety of important potentials in the fields of drug delivery and controlled release, biocoating, catalysis, and composite optoelectronic materials. use. In the classic preparation method of hollow spheres, the particles with core-shell structure are usually obtained by suspension or emulsion polymerization, and then the core part is removed by chemical or physical methods. The hollow spheres thus obtained often have a single structure and no Complete, further functional modification is difficult, and these defects limit the application of hollow spheres as noble metal nanoparticle carriers to prepare functional hybrid microspheres. In recent years, self-assembly technology has been used in the preparation of hollow spheres. Compared with the traditional hollow sphere preparation method, the self-assembly technology completely adopts physical methods, which avoids the special treatment steps required for using templates in the preparation process, and the obtained hollow spheres have a more uniform particle size distribution, and the hollow sphere structure and functionalization The control is more convenient, and this method is easier to combine the hollow structure characteristics of the ball and the functional characteristics of the noble metal nanoparticles to obtain new functional materials. So far, among the functional hybrid materials related to hollow spheres and noble metal nanoparticles, self-assembly technology has accounted for the majority (Wong.MS, et al.Nano Lett.; 2002, 2, 583).

The method of preparing hybrid hollow spheres through molecular assembly is very attractive, and it is easier to apply it in drug encapsulation and delivery, catalysis, development of artificial cells, and protection of biologically active reagents. However, the hybrid hollow spheres prepared by self-assembly technology are basically limited to two-block copolymers. The hollow spheres have a relatively simple structure and simple functions, because this technology requires that the block copolymer must have a suitable hydrophilic-lipophilic value, otherwise no hollow structure can be obtained by assembly (LiYT, Macromolecules.; 2007, 40, 8524). Therefore, finding a simpler method of preparing hollow sphere/noble metal nanoparticle hybrid materials, making the hybrid hollow sphere have intelligent response characteristics, strengthening the function of the hollow sphere and broadening its potential application ability, is the current research on the hybrid hollow sphere. problems that urgently need to be resolved.

Contents of the invention

The invention provides a polymer/noble metal nanoparticle hybrid hollow smart microsphere and a preparation method thereof.

The polymer/noble metal nanoparticle hybrid hollow smart microsphere of the present invention has the following components and weight percentages:

Noble metal nanoparticles 0.001%-0.01%

Polymer 99.99%-99.999%

The noble metal nanoparticles include gold nanoparticles (AuNP), silver nanoparticles (AgNP) or palladium nanoparticles (PdNP), the size of which is in the range of 5-20nm.

The polymer is firstly one or several block copolymers, one section of which is composed of one type of polymer chain, and the other section is formed by random arrangement of two types of macromolecules.

The hybrid hollow smart microsphere is a hollow microsphere loaded with noble metal nanoparticles, the particle size is 50-300nm, the noble metal nanoparticles are fixed on the outer surface of the microsphere, and the inner and outer layers of the hollow microsphere are made of the same type The hydrophilic polymer chain is composed of the hollow sphere wall is composed of a hydrophobic polymer chain.

The preparation method of the polymer/noble metal nanoparticle hybrid hollow smart microsphere of the present invention is as follows:

a) Put tert-butyl acrylate (tBA) in a glass sealed tube, add cuprous chloride and 1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA), and use atom transfer radical Polymerization obtains polytert-butyl acrylate homopolymer (PtBA);

b) Dissolve the homopolymer of polytert-butyl acrylate obtained in step (a) in an organic solvent in a glass sealed tube, add a monomer containing a carbon-carbon double bond, cuprous chloride and tris(2-dimethyl Aminoethyl) amine (Me6TREN), adopts atom transfer radical polymerization method to obtain block copolymer;

c) hydrolyzing the block copolymer obtained in step (b) in a trifluoroacetic acid/dichloromethane solution to obtain a block-random copolymer;

d) The block-random copolymer obtained in step (c) is directly dissolved in a mixed solution of dimethylformamide (DMF) and water (H ₂ O), and the mixed solution is dialyzed to obtain a block-random copolymer Hollow microsphere suspension;

e) adding a certain concentration of noble metal salt solution to the hollow microsphere suspension, and reducing it with excess sodium borocyanide to obtain hybrid hollow smart microspheres.

The monomer containing a carbon-carbon double bond refers to N-isopropylacrylamide (NIPAM), (dimethylamino) ethyl methacrylate (DMAEMA) or 4-vinylpyridine (4-VP ), the mass ratio of the added monomer to the homopolymer of tert-butyl polyacrylate is 1:1-3:1.

Described organic solvent can be the mixture of toluene, ethyl ketone/isopropanol or N, N-dimethylformamide/water, and the mass ratio of solvent and polyacrylate tert-butyl ester homopolymer is 1: 1-1.2: 1.

The polymer/precious metal nanoparticle hybrid intelligent hollow microsphere prepared by the present invention, the noble metal nanoparticle is located on the outer surface, is a kind of high-efficiency catalyst, and the test results of the aqueous phase catalytic reduction of p-nitrophenol show that the hollow polymer microsphere It has high catalytic reaction activity at room temperature, and its catalytic reaction rate can be adjusted conveniently, with temperature-sensitive intelligent characteristics. The outstanding advantage of the present invention is that the functions of the hollow microspheres, the functions of the noble metal nanoparticles and the intelligent characteristics of the material are skillfully combined together, and the noble metal nanoparticles can be adjusted conveniently by adjusting the structure of the hydrophilic chains of the inner and outer layers. Catalytic performance, is a new type of catalytic material. In addition, the combination of hollow smart structures and metal nanoparticles can also make it promising in the biomedical fields of selective catalysis and in situ diagnosis and therapy.

Detailed ways

Example 1.

1. Add 0.136g of initiator BMP, 0.075g of catalyst CuCl, 0.13g of complexing agent PMDETA and 15g of monomer tBA into a 25mL sealed tube. Vacuumize and fill with nitrogen in an ice-water bath, repeat 3 times, and seal the tube under vacuum. React in an oil bath at 90°C for 8h to stop the reaction. The polymer was dissolved with dichloromethane, and impurities such as catalysts were removed through a neutral Al ₂ O ₃ chromatographic column. Precipitate in methanol and dry in vacuo to give PtBA as a white solid;

2. Add 2.75g of initiator PtBA, 0.031g of catalyst CuCl, 0.067g of complexing agent Me ₆ TREN, a mixed solvent of butanone/isopropanol with a volume ratio of 6:4 and the second monomer NIPAM into a 25mL sealed tube. . Vacuumize and fill with nitrogen in an ice-water bath, repeat 3 times, and seal the tube under vacuum. React in a water bath at 40°C for 48h and stop the reaction. The polymer was dissolved with dichloromethane, and impurities such as catalysts were removed through a neutral Al ₂ O ₃ chromatographic column. Repeated precipitation in methanol/water, vacuum drying to obtain white solid poly(tert-butyl acrylate)-b-poly(N-isopropylacrylamide) (PtBA-b-PN IPAM);

3. Add 20mL of dichloromethane, 0.6g of PtBA-b-PN IPAM and 2mL of trifluoroacetic acid into a 50mL Erlenmeyer flask, and stir electromagnetically at 20°C for 5h. The solvent was removed by rotary evaporation, dialyzed with water, and freeze-dried to obtain the hydrolyzate P(AA-co-tBA)-b-PN IPAM.

4. Dissolve 0.050 g of block-random copolymer P(tBA-co-AA)-b-PNIPAM directly in 90 mL of double distilled water and 10 mL of DMF mixed solvent with pH 10, sonicate for 0.5 h, and dialyze for 4 d to form a concentration It is a micellar solution of 5×10 ^-4 g/mL.

5. A certain concentration of chloroauric acid solution (prepared by dissolving chloroauric acid in water with a pH of 7) was added to the 10 mL micellar solution prepared in advance, and stirred at room temperature for 24 hours. Under stirring, the newly prepared 5-fold excess sodium borohydride aqueous solution (prepared by dissolving sodium borohydride in water with a pH of 7) was directly added to the colloid solution treated with chloroauric acid to obtain hybrid hollow smart microspheres.

Block-random copolymer/gold nanoparticles hybrid hollow smart microspheres, the microspheres have good morphology, and the particle size distribution of gold nanoparticles on the surface of the microspheres is uniform. It is used to catalyze the reduction of p-nitrophenol and hybrid polymerization The microspheres exhibit high catalytic activity at room temperature, and the catalytic reaction rate can be adjusted by changing the temperature.

Example 2

1. Using the homopolymer of tert-butyl acrylate described in Example 1, add 2.75g of initiator PtBA, 0.031g of catalyst CuCl, 0.067g of complexing agent _Me6TREN , 5mL of DMF/ _H2O into a 25mL sealed tube Mixed solvent and 3g of the second monomer DMAEMA. Vacuumize and fill with nitrogen in an ice-water bath, repeat 3 times, and seal the tube under vacuum. React in a water bath at 40°C for 5h to stop the reaction. The polymer was dissolved with dichloromethane, and impurities such as catalysts were removed through a neutral Al ₂ O ₃ chromatographic column. Repeated precipitation in methanol/water, vacuum drying to obtain light yellow solid PtBA-b-PDMAEMA;

2. Add 20mL of dichloromethane, 1.5g of PtBA-b-PDMAEMA and 1mL of trifluoroacetic acid into a 50mL Erlenmeyer flask, and stir electromagnetically at 20°C for 10h. The solvent was removed by rotary evaporation, dialyzed with water, and freeze-dried to obtain the hydrolyzate P(AA-co-tBA)-b-PDMAEMA.

3. Dissolve 0.50 g of block-random copolymer P(tBA-co-AA)-b-PDMAEMA directly in 90 mL of double-distilled water and 10 mL of DMF mixed solvent with a pH of 6-7, sonicate for 0.5 h, and dialyze for 4 d , forming a micellar solution with a concentration of 5×10 ^-3 g/mL.

4. Add a certain concentration of silver nitrate solution (prepared by dissolving silver nitrate in water with a pH of 7) into the previously prepared 10 mL micellar solution, and stir at room temperature for 24 hours. Under stirring, a newly prepared 5-fold excess sodium borohydride aqueous solution (prepared by dissolving sodium borohydride in water with a pH of 7) was directly added to the silver nitrate-treated colloidal solution to obtain hybrid hollow spheres. Compared with Example 1, the obtained hybrid hollow sphere is not much different.

Example 3

1. Using the poly-tert-butyl acrylate homopolymer described in Example 1, add a certain amount of 2.75g initiator PtBA, 0.031g catalyst CuCl, 0.067g complexing agent Me _TREN , 3mL toluene solvent respectively in a 25mL sealed tube and 5 g of the second monomer 4-vinylpyridine. Vacuumize and fill with nitrogen in an ice-water bath, repeat 3 times, and seal the tube under vacuum. React in a water bath at 40°C for 72h and stop the reaction. The polymer was dissolved with dichloromethane, and impurities such as catalysts were removed through a neutral Al ₂ O ₃ chromatographic column. Repeated precipitation in methanol/water, vacuum drying to obtain light yellow solid PtBA-b-P4VP;

2. Add 10mL of dichloromethane, 0.5g of PtBA-b-P4VP and 0.6mL of trifluoroacetic acid into a 50mL Erlenmeyer flask, and stir electromagnetically at 20°C for 3h. The solvent was removed by rotary evaporation, dialyzed with water, and freeze-dried to obtain the hydrolyzate P(AA-co-tBA)-b-P4VP.

3. Dissolve 1 g of the block-random copolymer P(tBA-co-AA)-b-P4VP directly in 50 mL of double distilled water and 50 mL of DMF mixed solvent with a pH of 2-3, sonicate for 0.5 h, and dialyze for 4 d to form A micellar solution with a concentration of 1×10 ^-2 g/mL.

4. Add a certain concentration of palladium chloride solution (prepared by dissolving palladium chloride in water with a pH of 7) into the previously prepared 10 mL micellar solution, and stir at room temperature for 24 h. Under stirring, the newly prepared 5-fold excess sodium borohydride aqueous solution (prepared by dissolving sodium borohydride in water with a pH of 7) was directly added to the colloid solution treated with chloroauric acid to obtain hybrid hollow smart microspheres.

The polymer/noble metal nanoparticle hybrid hollow microspheres proposed by the present invention and the preparation method thereof have been described through examples, and those skilled in the art can clearly understand the content, spirit and scope of the present invention. The content is modified or appropriately modified and combined to realize the present invention. In particular, it should be pointed out that all similar substitutions and modifications would be obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims (9)

1. A polymer/noble metal nanoparticle hybrid hollow smart microsphere, its components and weight percentages are as follows: Noble metal nanoparticles 0.001%-0.01% Polymer 99.99%-99.999%. 2. The polymer/noble metal nanoparticle hybrid hollow smart microsphere according to claim 1, characterized in that the particle size of the microsphere is 50-300nm. 3. The polymer/precious metal nanoparticle hybrid hollow smart microsphere according to claim 1 is characterized in that the inner and outer layers of the hollow microsphere are made up of the same type of hydrophilic polymer chains, and the hollow sphere wall is composed of A hydrophobic polymer chain composition. 4. The polymer/precious metal nanoparticle hybrid hollow smart microsphere according to claim 1, the included polymer refers to one or several block copolymers, one section of which is made up of a type of polymer chain , and the other section is formed by random arrangement of acrylic acid and tert-butyl acrylate. 5. The polymer/noble metal nanoparticle hybrid hollow smart microsphere according to claim 1, characterized in that the noble metal nanoparticles include gold nanoparticles, silver nanoparticles or palladium nanoparticles, and the size is in the range of 5-20nm. 6. The polymer/noble metal nanoparticle hybrid hollow smart microsphere according to claim 1, characterized in that the noble metal nanoparticle is on the outer surface of the hybrid hollow smart microsphere. 7. the preparation method of polymer/precious metal nanoparticle hybrid intelligent hollow microsphere according to claim 1, is characterized in that the steps are as follows: a) Put tert-butyl acrylate (tBA) in a glass sealed tube, add cuprous chloride and 1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA), and use atom transfer radical Polymerization (ATRP) to obtain polytert-butyl acrylate homopolymer (PtBA); B) the polytert-butyl acrylate homopolymer (PtBA) that step (a) obtains is dissolved in the glass sealing tube with organic solvent, adds a kind of monomer containing carbon-carbon double bond, cuprous chloride and three (2 -Dimethylaminoethyl)amine (ME6TREN), a block copolymer obtained by atom transfer radical polymerization; c) hydrolyzing the block copolymer obtained in step (b) in a trifluoroacetic acid/dichloromethane solution to obtain a block-random copolymer; d) directly dissolving the block-random copolymer obtained in step (c) in a mixed solution of dimethylformamide and water, and dialyzing the mixed solution to obtain a polymer micelle suspension; e) adding a noble metal salt to the micellar suspension, and reducing it with excess sodium borocyanide to obtain hybrid hollow smart microspheres. 8. The preparation method according to claim 7, characterized in that the carbon-carbon double bond monomers included refer to N-isopropylacrylamide (NIPAM), (dimethylamino) ethyl methacrylate (DMAEMA ) or 4-vinylpyridine (4-VP), the mass ratio of the added monomer to the homopolymer of tert-butyl polyacrylate is 1:1-3:1. 9. preparation method according to claim 7 is characterized in that used organic solvent can be the mixture of toluene, butanone/isopropanol or N,N-dimethylformamide/water, solvent and polyacrylic acid tert-butyl The mass ratio of the ester homopolymer is 1:1-1.2:1.