A method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles

Abstract

The application provides a metal-doped titanium dioxide nanowire / block copolymer composite nanoparticle and a preparation method thereof, and belongs to the technical field of composite materials. The titanium dioxide nanowire is doped with metal, so that the physical and chemical properties of the titanium dioxide nanowire are improved, and the compounding capacity with the block copolymer is enhanced. In the application, a UV photopolymerization-induced self-assembly method is adopted, under the condition of UV light, macromolecular chain transfer agent of poly-4-vinylpyridine and styrene monomers are co-assembled with the metal-doped titanium dioxide nanowire in an in-situ polymerization process, so that a novel titanium dioxide nanowire / block copolymer composite nanoparticle is prepared. The application has the advantages of simple experimental operation, high yield and adjustable size of the nanomaterial, and can control the morphology of the composite nanoparticle through parameters such as UV light intensity, type of the metal-doped titanium dioxide nanowire, monomer amount and reaction time in the in-situ polymerization process in one step.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and in particular to a method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles. Background Technology

[0002] Inorganic / polymer composite nanoparticles represent an important new class of materials that leverage the complementary advantages of polymers and inorganic nanomaterials. In these composites, the polymer portion is predominantly homopolymer, and the morphology of the composite particles is relatively uniform. Compared to homopolymers, block copolymers can have their self-assembly behavior controlled by altering molecular weight, block composition, and solvent properties, resulting in richer and more sophisticated polymer nanostructures.

[0003] Typically, the preparation of inorganic / block copolymer composite nanoparticles involves first synthesizing block polymers with precise structures, and then self-assembling the inorganic nanoparticles with the block copolymers using solvent-induced polymerization, dialysis, or other methods to obtain the final inorganic / block copolymer composite nanoparticles. However, current methods are complex, have low yields, produce composite nanoparticles with irregular morphologies, and struggle to achieve controllable morphology control during in-situ polymerization.

[0004] One-dimensional titanium dioxide nanowires are one of the important forms of titanium dioxide, attracting widespread research due to their oriented one-dimensional structure, large specific surface area, and easily separable photogenerated electron-hole properties. One-dimensional titanium dioxide nanowires possess unique optical, electrical, and thermal properties. One-step in-situ composite formation of one-dimensional titanium dioxide nanowires with block copolymers yields novel inorganic / block copolymer composite nanoparticles, which are expected to show broad application prospects in biomedicine, catalysis, sensing, and self-assembly. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a metal-doped titanium dioxide nanowire / block copolymer composite nanoparticle. The method provided by this invention is simple to operate and the resulting composite nanoparticles have a regular morphology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles, comprising the following steps:

[0008] Nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate and doped metal nitrate are mixed and ground to obtain precursor powder, wherein the doped metal is one or more of cobalt, chromium and cadmium.

[0009] The precursor powder is heated and melted, and after cooling, a solid product is obtained. The solid product is then transferred to water and boiled to obtain metal-doped titanium dioxide nanowires.

[0010] The metal-doped titanium dioxide nanowires, poly(4-vinylpyridine) macromolecular chain transfer agent, styrene, photoinitiator and methanol were mixed and polymerized under ultraviolet light to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles.

[0011] Preferably, the mass ratio of the nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate and metal nitrate is 1:4:1:0.6-1.

[0012] Preferably, the particle size of the nano-titanium dioxide is 10-50 nm; the nano-titanium dioxide is titanium dioxide P25.

[0013] Preferably, the heating and melting temperature is 700–900°C, and the holding time is 6–12 hours.

[0014] Preferably, the length of the metal-doped titanium dioxide nanowire is 1 to 10 μm and the aspect ratio is 100 to 1000:1.

[0015] Preferably, the mass ratio of the metal-doped titanium dioxide nanowires to poly(4-vinylpyridine) is 1–50:100; and the mass ratio of poly(4-vinylpyridine) to styrene is 1:10–50.

[0016] Preferably, the photoinitiator is an azo photoinitiator; the mass ratio of poly(4-vinylpyridine) to the photoinitiator is 1:0.001 to 0.01.

[0017] Preferably, the intensity of the ultraviolet light source is 1–10 mW / cm². 2 The polymerization reaction time is 3 to 12 hours.

[0018] The present invention provides metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles prepared by the above preparation method, comprising metal-doped titanium dioxide nanowires and block copolymer micelle nanoparticles loaded on the surface of the metal-doped titanium dioxide nanowires, wherein the block copolymer micelle nanoparticles are poly(4-vinylpyridine-b-polystyrene) block copolymers.

[0019] This invention provides a method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles, comprising the following steps: mixing nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate, and a doped metal nitrate, grinding to obtain a precursor powder, wherein the doped metal is one or more of cobalt, chromium, and cadmium; heating and melting the precursor powder, cooling to obtain a solid product, transferring the solid product to deionized water and boiling to obtain metal-doped titanium dioxide nanowires; mixing the metal-doped titanium dioxide nanowires, poly(4-vinylpyridine) (P4VP) macromolecular chain transfer agent, styrene, a photoinitiator, and methanol, and performing a polymerization reaction under ultraviolet light to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles. This invention uses cobalt, chromium, and cadmium as doping elements, which can modify the surface of titanium dioxide nanowires, thereby improving their physicochemical properties and facilitating the composite of block copolymers and titanium dioxide nanowires. This invention uses poly(4-vinylpyridine) as a macromolecular chain transfer agent. Under ultraviolet light, the macromolecular chain transfer agent undergoes block polymerization with styrene, and during the in-situ polymerization process, it co-assembles with titanium dioxide nanowires to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles. This invention employs an ultraviolet light-induced polymerization self-assembly method, which has advantages such as simple experimental operation, high yield, and adjustable nanomaterial size. The morphology of the composite nanoparticles can be controlled by adjusting the ultraviolet light intensity, the type of metal-doped titanium dioxide nanowires, the monomer dosage, and the reaction time. Attached Figure Description

[0020] Figure 1 This is a SEM image of the cadmium-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained in Example 1 of this invention.

[0021] Figure 2 This is a SEM image of the chromium-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained in Example 2 of this invention.

[0022] Figure 3 This is a SEM image of the cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained in Example 3 of this invention.

[0023] Figure 4 This is a SEM image of the cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained in Example 4 of this invention.

[0024] Figure 5 This is a SEM image of the cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained in Example 5 of this invention.

[0025] Figure 6 This is a SEM image of the block copolymer nanoparticles obtained in Comparative Example 1 of the present invention.

[0026] Figure 7 This is a SEM image of the block copolymer nanoparticles obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0027] This invention provides a method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles, comprising the following steps:

[0028] Nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate and doped metal nitrate are mixed and ground to obtain precursor powder, wherein the doped metal is one or more of cobalt, chromium and cadmium.

[0029] The precursor powder is heated and melted, and after cooling, a solid product is obtained. The solid product is then transferred to water and boiled to obtain metal-doped titanium dioxide nanowires.

[0030] The metal-doped titanium dioxide nanowires, poly(4-vinylpyridine) macromolecular chain transfer agent, styrene, photoinitiator and methanol were mixed and polymerized under ultraviolet light to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles.

[0031] This invention involves mixing and grinding nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate, and a doped metal nitrate to obtain a precursor powder. The doped metal is one or more of cobalt, chromium, and cadmium. In this invention, the metal salt is preferably one or more of cobalt nitrate, chromium nitrate, and cadmium nitrate. The particle size of the nano-titanium dioxide is preferably 10–50 nm, more preferably 25 nm. The nano-titanium dioxide is preferably titanium dioxide P25.

[0032] In this invention, the preferred mass ratio of the nano-titanium dioxide, sodium chloride, disodium hydrogen phosphate, and metal salt is 1:4:1:0.6–1, more preferably 1:4:1:0.7–0.8. In this invention, the sodium chloride and disodium hydrogen phosphate act as molten salts.

[0033] The present invention does not have any special requirements for the grinding method; any grinding method known to those skilled in the art can be used.

[0034] This invention involves heating and melting the precursor powder, cooling it to obtain a solid product, and then boiling the solid product in water to obtain metal-doped titanium dioxide nanowires. Preferably, the heating and melting is performed in a tube furnace, and the heating and melting atmosphere is preferably nitrogen. In this invention, the water is preferably deionized water; the heating and melting temperature is preferably 700–900°C, more preferably 825°C, and the holding time is preferably 6–12 hours, more preferably 8 hours; the heating rate to the high-temperature melting growth is preferably 10°C / min. During the heating and melting process, the titanium dioxide in the precursor powder continuously grows, while the doping element modifies the surface elements of the titanium dioxide, forming metal-doped titanium dioxide nanowires with uniform size and tunable properties.

[0035] In this invention, the boiling temperature is preferably 100°C, and the boiling time is preferably 2 hours. The boiling is preferably carried out under stirring conditions, and the stirring rate is preferably 600 rpm. After heating and stirring, the product is preferably centrifuged, washed, and dried to obtain metal-doped titanium dioxide nanowire powder. The centrifugation rate is preferably 2000–4000 rpm, more preferably 3000 rpm, and the centrifugation time is preferably 15–45 minutes, more preferably 20–40 minutes. The washing agent is preferably ethanol.

[0036] In this invention, the length of the metal-doped titanium dioxide nanowire is preferably 1 to 10 μm, more preferably 4 to 8 μm, and the aspect ratio is preferably 100 to 1000:1, more preferably 400 to 800:1.

[0037] This invention involves mixing the aforementioned metal-doped titanium dioxide nanowires, poly(4-vinylpyridine), styrene, a photoinitiator, and methanol, and then performing a polymerization reaction under ultraviolet light to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles. In this invention, the molecular weight of the poly(4-vinylpyridine) is preferably 1000–20000, more preferably 5000–15000.

[0038] In this invention, the photoinitiator is preferably an azo photoinitiator, and more preferably azobisisobutyronitrile (AIBN).

[0039] In this invention, the mass ratio of the metal-doped titanium dioxide nanowires to poly(4-vinylpyridine) is preferably 1-50:100, more preferably 15-30:100; the mass ratio of the poly(4-vinylpyridine) to styrene is preferably 1:10-50, more preferably 1:20-40.

[0040] In this invention, the mass ratio of poly(4-vinylpyridine) to photoinitiator is preferably 1:0.001 to 0.01, more preferably 1:0.003 to 0.006.

[0041] In this invention, the intensity of the ultraviolet light source is preferably 1 to 10 mW / cm². 2 More preferably 20–40 mW / cm 2 The polymerization reaction time is preferably 3 to 12 hours, more preferably 5 to 10 hours.

[0042] This invention provides metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles obtained by the above preparation method, comprising one-dimensional metal-doped titanium dioxide nanowires and block copolymer micelle nanoparticles on the surface of the metal-doped titanium dioxide nanowires, wherein the block copolymer micelle nanoparticles are poly(4-vinylpyridine-b-polystyrene) block copolymer (P4VP-b-PS). In this invention, the metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles have a "beaded" structure, and the length of the metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles is preferably 1-10 μm, and the diameter is preferably 2 μm.

[0043] The following detailed description of the preparation method of the metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] 100 mg disodium hydrogen phosphate, 400 mg sodium chloride, 100 mg titanium dioxide P25 and 77 mg cadmium nitrate were ground into a homogeneous mixture; transferred to a crucible, heated at a rate of 10 °C / min to 825 °C, and reacted under N2 atmosphere for 6 h; washed in boiling water, centrifuged at 5000 rpm for 30 min, and vacuum dried to collect the product, thus obtaining cadmium-doped titanium dioxide nanowires.

[0046] 0.01 g of cadmium-doped titanium dioxide nanowires, 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN were added sequentially to a quartz glass bottle and dissolved in 6.0 mL of methanol. Then, at 5 mW / cm²... 2 The polymerization reaction was carried out under ultraviolet light for 9 hours. After centrifugation at 6000 rpm for 15 minutes, the precipitate was collected, washed three times with ethanol, and dried to obtain cadmium-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The morphology of the obtained cadmium-doped titanium dioxide nanowire / block copolymer composite nanoparticles is shown in the figure below. Figure 1 As shown. By Figure 1It can be seen that a large number of block copolymer nanoparticles are attached to the surface of cadmium-doped titanium dioxide nanowires, indicating that a novel composite nanostructure has been successfully prepared.

[0047] Example 2

[0048] 100 mg disodium hydrogen phosphate, 400 mg sodium chloride, 100 mg titanium dioxide P25 and 77 mg chromium nitrate were ground into a homogeneous mixture; transferred to a crucible, heated at a rate of 10 °C / min to 825 °C, and reacted under N2 atmosphere for 6 h; washed in boiling water, centrifuged at 5000 rpm for 30 min, and vacuum dried to collect the product, thus obtaining chromium-doped titanium dioxide nanowires.

[0049] 0.01 g of chromium-doped titanium dioxide nanowires, 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN were added sequentially to a quartz glass bottle and dissolved in 30 mL of methanol. Then, at 5 mW / cm², [the solution was applied]. 2 The polymerization reaction was carried out under ultraviolet light for 9 h. After centrifugation at 6000 rpm for 15 min, the precipitate was collected, washed three times with ethanol, and dried to obtain chromium-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The morphology of the obtained chromium-doped titanium dioxide nanowire / block copolymer composite nanoparticles is shown in the figure. Figure 2 As shown. By Figure 2 It can be seen that a large number of block copolymer nanoparticles are attached to the surface of chromium-doped titanium dioxide nanowires, indicating that a new type of composite nanomaterial has been successfully prepared.

[0050] Example 3

[0051] 100 mg disodium hydrogen phosphate, 400 mg sodium chloride, 100 mg P25 and 73 mg cobalt nitrate were ground into a homogeneous mixture; transferred to a crucible, heated at a rate of 10 °C / min to 825 °C, and reacted under N2 atmosphere for 6 h; washed in boiling water, centrifuged at 5000 rpm for 30 min, and vacuum dried to collect the product, thus obtaining cobalt-doped titanium dioxide nanowires.

[0052] 0.01 g of cobalt-doped titanium dioxide nanowires, 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN were added sequentially to a quartz glass bottle and dissolved in 30 mL of methanol. Then, at 5 mW / cm²... 2 The polymerization reaction was carried out under ultraviolet light for 9 h. After centrifugation at 6000 rpm for 15 min, the precipitate was collected, washed three times with ethanol, and dried to obtain cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The morphology of the obtained cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles is as follows. Figure 3 As shown. By Figure 3It can be seen that a large number of block copolymer nanoparticles are attached to the surface of cobalt-doped titanium dioxide nanowires, indicating that a novel composite nanomaterial has been successfully prepared.

[0053] Example 4

[0054] Cobalt-doped titanium dioxide nanowires were prepared according to the method in Example 3;

[0055] 0.02 g of cobalt-doped titanium dioxide nanowires, 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN were added sequentially to a quartz glass bottle, dissolved in 30 mL of methanol, and then placed in a 5 mW / cm² container. 2 The polymerization reaction was carried out under UV light for 9 h. After centrifugation at 6000 rpm for 15 min, the precipitate was collected, washed three times with ethanol, and dried to obtain cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The morphology of the obtained cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles is shown in the figure. Figure 4 As shown. By Figure 4 It can be seen that a large number of block copolymer nanoparticles are attached to the surface of cobalt-doped titanium dioxide nanowires, indicating that a novel composite nanomaterial has been successfully prepared.

[0056] Example 5

[0057] Cobalt-doped titanium dioxide nanowires were prepared according to the method in Example 3;

[0058] 0.01 g of cobalt-doped titanium dioxide nanowires, 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN were added sequentially to a quartz glass bottle, dissolved in 30 mL of methanol, and then placed in a 5 mW / cm² container. 2 The polymerization reaction was carried out under UV light for 3 hours. After centrifugation at 6000 rpm for 15 minutes, the precipitate was collected, washed three times with ethanol, and dried to obtain cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The morphology of the obtained cobalt-doped titanium dioxide nanowire / block copolymer composite nanoparticles is as follows. Figure 5 As shown. By Figure 5 It can be seen that a large number of block copolymer nanoparticles are attached to the surface of cobalt-doped titanium dioxide nanowires, indicating that a novel composite nanostructure has been successfully prepared.

[0059] Comparative Example 1

[0060] Add 40 mg of polymer P4VP, 0.9 g of styrene, and 0.2 mg of initiator AIBN sequentially to a quartz glass bottle, dissolve them in 30 mL of methanol, and then place the solution at 5 mW / cm². 2The polymerization reaction was carried out under UV irradiation for 9 hours. After centrifugation at 6000 rpm for 15 min, the precipitate was collected, washed three times with ethanol, and dried to obtain single block copolymer nanoparticles. The morphology of the obtained block copolymer nanoparticles is as follows. Figure 6 As shown. By Figure 6 It can be seen that the prepared block copolymer micelle nanoparticles have a relatively uniform size distribution, with a particle size of approximately 200 nm.

[0061] Comparative Example 2

[0062] Add 0.01g of nano-titanium dioxide P25, 40mg of polymer P4VP, 0.9g of styrene, and 0.2mg of initiator AIBN sequentially to a quartz glass bottle, dissolve in 30mL of methanol, and then place it at 5mW / cm². 2 The polymerization reaction was carried out under UV irradiation for 9 hours. After centrifugation at 6000 rpm for 15 min, the precipitate was collected, washed three times with ethanol, and dried to obtain single block copolymer nanoparticles. The morphology of the obtained block copolymer nanoparticles is as follows. Figure 7 As shown. By Figure 7 It can be seen that not only can the prepared block copolymer micelle nanoparticles not be combined with titanium dioxide P25, but the size distribution of the generated block copolymer micelles is also uneven.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles, comprising the following steps: mixing nanometer titanium dioxide, sodium chloride, disodium hydrogen phosphate and metal nitrate, grinding to obtain a precursor powder, wherein the metal is one or more of cobalt, chromium and cadmium; heating and melting the precursor powder, and obtaining a solid product after cooling; transferring the solid product to water and boiling to obtain metal-doped titanium dioxide nanowires; mixing the metal-doped titanium dioxide nanowires, poly-4-vinylpyridine macromolecular chain transfer agent, styrene, a photoinitiator and methanol, and performing a polymerization reaction under ultraviolet light to obtain metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles. The nanometer titanium dioxide has a particle size of 10-50 nm. The metal-doped titanium dioxide nanowires have a length of 1-10 μm and an aspect ratio of 100-1000:

1. The mass ratio of the metal-doped titanium dioxide nanowires to poly-4-vinylpyridine is 1-50:100, and the mass ratio of poly-4-vinylpyridine to styrene is 1:10-50. The mass ratio of the nanometer titanium dioxide, sodium chloride, disodium hydrogen phosphate and metal nitrate is 1:4:1:0.6-1. The nanometer titanium dioxide is titanium dioxide P25. The temperature of the heating and melting is 700-900 ℃, and the holding time is 6-12 h.

2. The production method according to claim 1, characterized by, The photoinitiator is an azo photoinitiator, and the mass ratio of poly-4-vinylpyridine to the photoinitiator is 1:0.001-0.

01.

3. The preparation method according to claim 1, characterized in that, 7.The metal-doped titanium dioxide nanowire / block copolymer composite nanoparticles prepared by the method of any one of claims 1-6, comprising metal-doped titanium dioxide nanowires and block copolymer micellar nanoparticles loaded on the surface of the metal-doped titanium dioxide nanowires, wherein the block copolymer micellar nanoparticles are poly-4-vinylpyridine-b-poly-styrene block copolymers.

4. The method of claim 1, wherein, ​ 5. The preparation method according to claim 1, characterized in that, ​ 6. The method of claim 1, wherein, The light source intensity of the ultraviolet light is 1-10 mW / cm 2 ; the polymerization reaction time is 3-12 h. ​

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