A tubular micromotor of MOF annealed material and preparation method thereof

Abstract

The present invention relates to a tubular micromotor of MOF annealing material and a preparation method thereof, the preparation method comprising: preparing ZIF-67; taking a porous polycarbonate template A1 and a porous polycarbonate template A2, cleaning and drying them respectively, and then using a thermal evaporation instrument to evaporate a layer of metal on one side of the porous polycarbonate template A1 as a substrate; dissolving ZIF-67 in deionized water to obtain a ZIF-67 dispersion, passing the ZIF-67 dispersion through the stacked porous polycarbonate template A2 and the porous polycarbonate template A1 in sequence, taking out the porous polycarbonate template A1 as a tubular micro-nano motor precursor; using dichloromethane to post-treat the tubular micro-nano motor precursor so that the porous polycarbonate template is dissolved, and then centrifuging and washing to obtain a tubular micromotor of MOF annealing material. Compared with the prior art, the preparation method of the present invention is simple, and the obtained micro-nano motor not only has strong magnetism, but also has good adsorption capacity based on the inherent porous structure and porosity.

Description

Technical Field

[0001] The invention relates to the field of micro-nano motors, and in particular to a tubular micro-motor made of MOF annealing material and a preparation method thereof. Background Art

[0002] Since its emergence in 2002, micromotors have become one of the most important research areas in nanotechnology. Self-driven micro-nanomotors have attracted much attention due to their intelligent trend. So far, micromotors have been widely used in drug delivery, biosensing, imaging, environmental remediation, and bacterial separation.

[0003] In order to realize bubble-driven micromotors, it is necessary to dope expensive, toxic, and unstable catalysts, or add expensive metals or high concentrations of toxic chemical fuels, which severely limits their practical applications. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a tubular micromotor of MOF annealing material and a preparation method thereof. The preparation method is simple, and the obtained micro-nano motor not only has strong magnetism, but also has good adsorption capacity based on the inherent porous structure and porosity.

[0005] During the conception process, the applicant believed that in order to break through these limitations, integrating highly ordered porous materials with large surface areas into colloidal motors is a promising strategy to improve their self-propulsion speed and adsorption, which will be beneficial to many applications. Therefore, this technical solution selected ZIF-67 as a MOF material as a precursor of the micromotor. By annealing ZIF-67, a magnetic Co nanocomposite material can be obtained.

[0006] Although single annealed MOF particles have chemical drivability in existing studies, they are not broadly feasible and practical, and act as carrier payloads. Therefore, this technical solution uses these annealed particles to prepare tubular micro-nanomotors, which are convenient for unified control and application, and can be mass-produced, stable and biocompatible. At the same time, the tubular template can be changed for directional self-driven directional movement or transportation. Due to the presence of magnetic Co, their movement can be controlled in a magnetic field, so they can be applied to environmental remediation, recovery under magnetic control, and stable recycling capabilities and high selectivity. This self-propelled magnetic recyclable micro-nanomotor can play a role in the management and remediation of radioactive waste in the future, and provides great inspiration and opportunities for improving the efficiency and precise release of drugs in drug delivery systems.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The first object of the present invention is to provide a method for preparing a tubular micromotor of MOF annealing material, comprising the following steps:

[0009] S1: preparing ZIF-67 and grinding it into ZIF-67 powder particles;

[0010] S2: Clean and dry the porous polycarbonate template A1 and the porous polycarbonate template A2 respectively, and then use a thermal evaporation apparatus to deposit a layer of metal on one side of the porous polycarbonate template A1 as a substrate;

[0011] S3: dissolving the ZIF-67 obtained in S1 in deionized water to obtain a ZIF-67 dispersion, passing the ZIF-67 dispersion through the stacked porous polycarbonate template A2 and the porous polycarbonate template A1 in sequence, and taking out the porous polycarbonate template A1 as a tubular micro-nanomotor precursor;

[0012] S4: post-treating the tubular micro-nanomotor precursor obtained in S3 with dichloromethane to dissolve the porous polycarbonate template, followed by centrifugation and washing to obtain a tubular micromotor of MOF annealed material.

[0013] Furthermore, in S1, the ZIF-67 is synthesized using 2-methylimidazole, cobalt sulfate heptahydrate and polyvinyl pyrrolidone as raw materials.

[0014] Furthermore, in S1, the composition of the raw materials required for ZIF-67 includes 0.05 mol / L CoSO4·7H2O, 0.004 mol / L polyvinyl pyrrolidone, and 0.8 mol / L 2-methylimidazole.

[0015] Further, in S1, the preparation process of ZIF-67 includes:

[0016] After 2-methylimidazole, cobalt sulfate heptahydrate and polyvinyl pyrrolidone are prepared into a solution, the solution is kept at room temperature for 24 hours, and then the supernatant is separated and the lower product is retained. After post-treatment, ZIF-67 is obtained.

[0017] Furthermore, the post-treatment process includes: washing the retained lower product with alcohol and deionized water in turn at a rotation speed of 6000 rpm for 10 minutes, and washing each solution 5 times, and then vacuum drying to obtain ZIF-67.

[0018] Furthermore, the prepared ZIF-67 was annealed at 800°C and then ground into powder particles;

[0019] The parameters set during the annealing process are:

[0020] Initial temperature: 30℃;

[0021] Heating time: 154min;

[0022] Final temperature: 800℃;

[0023] Holding time: 180min;

[0024] Heating rate: 5°C / min.

[0025] Furthermore, in S2, a layer of metal Au is evaporated on one side of the porous polycarbonate template A1 using a thermal evaporation apparatus as a substrate.

[0026] Further, in S3, when the porous polycarbonate template A2 and the porous polycarbonate template A1 are stacked, the side of the porous polycarbonate template A1 coated with Au is placed at the bottom;

[0027] The filtration process circulates the filtered solution through the stacked porous polycarbonate template A2 and the porous polycarbonate template A1 in sequence.

[0028] Furthermore, the tubular micro-nanomotor precursor was dissolved with dichloromethane, and then the dissolved solution was placed in a centrifuge and centrifuged at 6000 rpm for 3 minutes with alcohol and water respectively, and each solution was washed three times in turn.

[0029] The second object of the present invention is to provide a tubular micromotor of the MOF annealed material obtained by the above method.

[0030] Compared with the prior art, the present invention has the following technical advantages:

[0031] 1) The preparation method of the present invention is simple, and the obtained micro-nano motor not only has strong magnetism, but also inherent porous structure and porosity, and has good adsorption capacity, and can be applied to efficient environmental management and the transportation, delivery and release of drugs in future medicine.

[0032] 2) This technical solution uses these annealed particles to prepare tubular micro-nanomotors, which are convenient for unified control and application. They can be mass-produced, stable and biocompatible, and the tubular template can be changed for directional self-driven directional movement or transportation. Due to the presence of magnetic Co, their movement can be controlled in a magnetic field, so they can be applied to environmental remediation, recovery under magnetic control, and stable recycling capacity and high selectivity. This self-propelled magnetic recyclable micro-nanomotor can play a role in the management and remediation of radioactive waste in the future, and provides great inspiration and opportunities for improving the efficiency and precise release of drugs in drug delivery systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a scanning electron microscope image of the tubular micro-nanomotor of annealed MOF in the technical solution (scale bar is 1 μm);

[0034] Figure 2 A physical picture of a tubular annealing furnace used in the embodiment;

[0035] Figure 3 This is a physical picture of the vacuum filtration device used in the embodiment;

[0036] Figure 4 This is the XRD data of the tubular micro-nanomotor of annealed MOF in this technical solution. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation methods, materials, structures or composition ratios not explicitly described in this technical solution are deemed to be common technical features disclosed in the prior art.

[0038] The tubular micro-nanomotor of the annealed MOF in this embodiment is a tubular structure with a length of 10-12 μm and a pore size of 5 μm, and is prepared by the following steps:

[0039] Step 1: First, 0.05 mol of cobalt sulfate heptahydrate (CoSO4·7H2O) and 0.004 mol of polyvinylpyrrolidone (PVP) were mixed and placed in 1L of deionized water, and then 0.8 mol of 2-methylimidazole (2-MeIM) was added for chemical reaction. The mixture was stirred vigorously for 30 minutes and allowed to stand at room temperature for 24 hours to achieve sufficient reaction. The synthetic raw material ZIF-67 is shown in the following table.

[0040] The composition of the ZIF-67 deposition solution is shown in the following table:

[0041]

[0042] The synthesized ZIF-67 product was stored at room temperature for 24 hours, after which the supernatant was separated and the lower product was retained.

[0043] Step 2: Use a centrifuge to wash the lower product in the separated beaker with deionized water at 6000 rpm for 10 minutes three times. The purpose of the centrifuge washing is to reduce impurities in the sample. Then dry it in a vacuum drying oven for 24 hours and grind it into powder particles.

[0044] Step 3: Place the powdered particles obtained in step 2 into a tubular annealing furnace such as Figure 2 As shown ( Figure 2The tubular annealing furnace used in the embodiment is used for annealing at a temperature of 800° C. The annealed material is vacuum dried for 24 hours and ground into powder particles for use as raw materials. The setting parameters of the tubular furnace during the annealing process are:

[0045] Initial temperature: 30℃;

[0046] Heating time: 154min;

[0047] Final temperature: 800℃;

[0048] Holding time: 180min;

[0049] Heating rate: 5°C / min.

[0050] Step 4: Take two porous polycarbonate templates and perform pretreatment A1 and A2, and then use a thermal evaporation instrument to evaporate a layer of gold on one side of the porous polycarbonate template A1 as a substrate;

[0051] Step 5: Dissolve the annealed ZIF-67 in deionized water, and then filter it in a vacuum filtration device such as Figure 3 As shown ( Figure 3 The vacuum filtration device used in the embodiment) was vacuum filtered for three minutes, so that the space where A1 and A2 were placed on the upper part formed a low pressure state, and the solution was passed through the pre-treated two porous polycarbonate templates A1 and A2 for accumulation and precipitation to prepare tubular micro-nanomotors, such as Figure 1 As shown ( Figure 1 This is a scanning electron microscope sample of the tubular micro-nanomotor of the annealed MOF in the present technical solution. During the filtration process, the filtered solution is recycled and sequentially passed through the stacked porous polycarbonate templates A2 and the porous polycarbonate template A1 to reach the compact particle accumulation tube.

[0052] Step 6: The template A2 deposited in step 5 is then placed in a drying oven at 60°C for 24 hours, and the porous polycarbonate template is dissolved with dichloromethane. Finally, a centrifuge is used to clean it three times with dichloromethane, alcohol, and water at 6000 rpm for 3 minutes each time to remove the porous polycarbonate template, thereby obtaining a multifunctional self-driven annealed MOF tubular micro-nanomotor. The speed of the micromotor at a concentration of 3% hydrogen peroxide is about 150 μm / s, which is faster than a single particle.

[0053] Step 7: Same as the above operation, it was found that using different ratios in the preparation process (the changed ratio is: the composition of the raw materials required for ZIF-67 includes 0.1mol / L CoSO4·7H2O, 0.008mol / L polyvinylpyrrolidone, and 0.8mol / L 2-methylimidazole), the prepared product has a certain degree of adverse effect on the particle size and the carbonization degree of the tubular micro-nanomotor of the annealed MOF, such as Figure 4 As shown ( Figure 4 The XRD data of the tubular micro-nanomotor of annealed MOF in the present technical solution) show that two peaks appear between 2θ=40° and 55°. The comparison shows that changing the ratio leads to an increase in crystallinity and an increase in the size of Co nanoparticles, which reduces the movement speed of the tubular micro-nanomotor and has an adverse effect on the application of the tubular micro-nanomotor of annealed MOF.

[0054] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a tubular micromotor of MOF annealed material, characterized in that: The following steps are involved: S1: preparing ZIF-67, annealing the prepared ZIF-67 at a temperature of 800° C., and then grinding it into ZIF-67 powder particles; S2: Clean and dry the porous polycarbonate template A1 and the porous polycarbonate template A2 respectively, and then use a thermal evaporation apparatus to deposit a layer of metal on one side of the porous polycarbonate template A1 as a substrate; S3: dissolving the ZIF-67 obtained in S1 in deionized water to obtain a ZIF-67 dispersion, passing the ZIF-67 dispersion through the stacked porous polycarbonate template A2 and the porous polycarbonate template A1 in sequence, and taking out the porous polycarbonate template A1 as a tubular micro-nanomotor precursor; S4: post-treating the tubular micro-nanomotor precursor obtained in S3 with dichloromethane to dissolve the porous polycarbonate template, and then centrifuging and washing to obtain a tubular micromotor of MOF annealing material; In S1, the ZIF-67 is synthesized using 2-methylimidazole, cobalt sulfate heptahydrate and polyvinyl pyrrolidone as raw materials; In S1, the composition of the raw materials required for ZIF-67 includes 0.05 mol / L CoSO4·7H2O, 0.004 mol / L polyvinylpyrrolidone, and 0.8 mol / L 2-methylimidazole; In S1, the preparation process of ZIF-67 includes: After 2-methylimidazole, cobalt sulfate heptahydrate and polyvinyl pyrrolidone are prepared into a solution, the solution is stored at room temperature for 24 hours, and then the supernatant is separated and the lower product is retained. After post-treatment, ZIF-67 is obtained; In S3, when the porous polycarbonate template A2 and the porous polycarbonate template A1 are stacked, the metal-plated side of the porous polycarbonate template A1 is placed at the bottom; The filtration process circulates the filtered solution through the stacked porous polycarbonate template A2 and the porous polycarbonate template A1 in sequence.

2. The method for preparing a tubular micromotor of MOF annealing material according to claim 1, characterized in that: The post-treatment process includes: washing the retained lower product with alcohol and deionized water at a rotation speed of 6000 rpm for 10 minutes, and washing each solution 5 times, and then vacuum drying to obtain ZIF-67.

3. The method for preparing a tubular micromotor of MOF annealing material according to claim 1, characterized in that: In S1, the parameters set during the annealing process are: Initial temperature: 30℃; Heating time: 154min; Final temperature: 800℃; Holding time: 180min; Heating rate: 5°C / min.

4. The method for preparing a tubular micromotor of MOF annealing material according to claim 1, characterized in that: In S2, a layer of metal Au is evaporated on one side of the porous polycarbonate template A1 using a thermal evaporation apparatus as a substrate.

5. The method for preparing a tubular micromotor of MOF annealing material according to claim 1, characterized in that: The tubular micro-nanomotor precursor was dissolved with dichloromethane, and then the dissolved solution was placed in a centrifuge and centrifuged at 6000 rpm for 3 minutes with alcohol and water respectively, and each solution was washed three times in turn.

6. A tubular micromotor of the MOF annealed material obtained by the method according to any one of claims 1 to 5.

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