Rod-like nano-zinc oxide and preparation method thereof

Abstract

This invention relates to a rod-shaped nano-zinc oxide and its preparation method. The method includes: reacting a zinc salt with a precipitant to generate a precipitate under the action of a dispersant; wherein the dispersant includes polyvinylpyrrolidone and a soluble chitosan derivative. The preparation method of the rod-shaped nano-zinc oxide of this invention is simple in steps and can produce rod-shaped nano-zinc oxide with uniform morphology.

Description

Technical Field

[0001] This invention relates to nano zinc oxide, and more particularly to a rod-shaped nano zinc oxide and its preparation method. Background Technology

[0002] Nano-zinc oxide is a novel inorganic nanomaterial with high functionality and added value. It possesses photosensitive, electrical, and magnetic properties not found in many other materials, can absorb and scatter ultraviolet light, and exhibits catalytic activity. It has been applied in various fields such as photocatalysis, thermistors, piezoelectric materials, gas sensing, sun protection, and antibacterial applications. The structure and morphology of nanomaterials have a significant impact on their performance and applications. Preparing nanomaterials with specific structures is of great academic and practical value for developing new areas of nanomaterial performance.

[0003] There are many methods for preparing nano-zinc oxide, with commonly used methods including liquid-phase precipitation, microemulsion method, chemical vapor deposition, sol-gel method, and hydrothermal synthesis. However, nano-zinc oxide prepared by these methods suffers from problems such as large particle size, poor dispersibility, or poor uniformity, affecting its application. Furthermore, preparing nano-zinc oxide with specific morphologies often requires different morphology control agents and special processes, such as ultrasound and hydrothermal methods. Some organic morphology control agents are difficult to remove and may be toxic to humans; ultrasound and hydrothermal processes significantly increase production costs.

[0004] For example, patent application CN110980798A discloses a method of dissolving zinc acetylacetonate in anhydrous methanol to obtain anhydrous zinc acetylacetonate solution, followed by solvothermal preparation of nano-zinc oxide microspheres with a particle size of 800–1000 nm. The zinc oxide nanospheres prepared by this method have uniform morphology, but large particle size, making them prone to sedimentation in solution; furthermore, a high-temperature reactor is required, making the process complex and energy-intensive. Another example is patent application CN113735158A, which discloses the preparation of spherical zinc oxide nanospheres using zinc nitrate hexahydrate as the zinc source and triethanolamine as the alkali source via a microwave hydrothermal method, while simultaneously grafting the high-molecular-weight surfactant sodium carboxymethyl cellulose onto the zinc oxide nanospheres in situ. The zinc oxide nanospheres prepared by this method have uneven morphology and large particle size; sodium carboxymethyl cellulose does not effectively control the morphology and particle size; moreover, the preparation process requires ultrasonic equipment, demanding high preparation conditions and is not suitable for industrial production. Summary of the Invention

[0005] Based on the above analysis, one embodiment of the present invention aims to provide a method for preparing rod-shaped nano zinc oxide, in order to solve the problems of complex processes or easy sedimentation or uneven morphology of zinc oxide in solution in existing preparation methods.

[0006] On one hand, one embodiment of the present invention provides a method for preparing rod-shaped nano zinc oxide, comprising: reacting zinc salt with a precipitant to generate a precipitate under the action of a dispersant; wherein the dispersant comprises polyvinylpyrrolidone and a soluble chitosan derivative.

[0007] According to one embodiment of the present invention, the weight-average molecular weight of the polyvinylpyrrolidone is 50,000 to 1,000,000, more specifically 55,000 to 60,000.

[0008] According to one embodiment of the present invention, the soluble chitosan derivative includes one or more of carboxymethyl chitosan and chitosan quaternary ammonium salts.

[0009] According to one embodiment of the present invention, the chitosan quaternary ammonium salt includes hydroxypropyltrimethylammonium chloride chitosan and chitosan hydrochloride; the weight-average molecular weight of the soluble chitosan derivative is 100,000 to 300,000.

[0010] According to one embodiment of the present invention, the mass ratio of the polyvinylpyrrolidone to the soluble chitosan derivative is (1-3):(1-3); and / or,

[0011] The mass ratio of the zinc salt to the soluble chitosan derivative is 2:(1-3).

[0012] According to one embodiment of the present invention, the zinc salt includes one or more of zinc acetate, zinc chloride, zinc nitrate, and zinc sulfate.

[0013] According to one embodiment of the present invention, the precipitant is one or more of ammonia, sodium hydroxide, and potassium hydroxide.

[0014] According to one embodiment of the present invention, the method includes:

[0015] A mixture is provided, the mixture comprising the zinc salt, polyvinylpyrrolidone, the soluble chitosan derivative, and water;

[0016] The precipitant is added to the mixture to obtain the precipitate; and

[0017] The precipitate is then dried.

[0018] On the other hand, one embodiment of the present invention provides a rod-shaped nano zinc oxide, which is prepared by the above method.

[0019] According to one embodiment of the present invention, the length of the rod-shaped zinc oxide nanoparticles is 300–1000 nm, and the cross-sectional diameter is 50–100 nm; and / or,

[0020] Polyvinylpyrrolidone and the chitosan derivative are attached to the rod-shaped zinc oxide nanoparticles.

[0021] The method for preparing rod-shaped nano zinc oxide according to one embodiment of the present invention is simple and can produce rod-shaped nano zinc oxide with uniform morphology.

[0022] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Wherein:

[0024] Figures 1A to 1D Here is a SEM image of the rod-shaped zinc oxide nanoparticles from Example 1;

[0025] Figure 2 The image shows the XRD pattern of rod-shaped zinc oxide nanoparticles from Example 1.

[0026] Figure 3 The image shows the ultraviolet spectrum of the rod-shaped zinc oxide nanoparticles from Example 1.

[0027] Figure 4 The infrared spectrum of rod-shaped zinc oxide nanoparticles from Example 1;

[0028] Figure 5 Figure 1 shows the bacterial growth of Escherichia coli after incubation for 24 hours with aqueous solutions of different concentrations of rod-shaped zinc oxide nanoparticles as an application example.

[0029] Figure 6 The survival rate of Escherichia coli after 24 hours of incubation with aqueous solutions of different concentrations of rod-shaped zinc oxide nanoparticles, as an application example;

[0030] Figure 7A Photographs of the aqueous dispersion system of rod-shaped nano zinc oxide in Example 1 and the aqueous dispersion system of zinc oxide in the control group when they were first formed.

[0031] Figure 7B Photographs of the aqueous dispersion system of rod-shaped nano zinc oxide from Example 1 and the aqueous dispersion system of zinc oxide from the control group after standing for 2 hours.

[0032] Figure 7C Photographs of the aqueous dispersion system of rod-shaped nano zinc oxide from Example 1 and the aqueous dispersion system of zinc oxide from the control group after standing for 3 hours.

[0033] Figure 7DPhotographs of the aqueous dispersion system of rod-shaped nano zinc oxide in Example 1 and the aqueous dispersion system of zinc oxide in the control group after standing for 24 hours.

[0034] Figure 8A , 8B Here is a SEM image of the rod-shaped zinc oxide nanoparticles from Example 2;

[0035] Figure 9 Here is a SEM image of the rod-shaped zinc oxide nanoparticles from Example 3;

[0036] Figure 10 Here is a SEM image of the rod-shaped zinc oxide nanoparticles from Example 4;

[0037] Figures 11A to 11D SEM image of nano zinc oxide from Comparative Example 1;

[0038] Figures 12A to 12D SEM image of nano-zinc oxide from Comparative Example 2;

[0039] Figure 13A , 13B SEM image of nano zinc oxide in Comparative Example 3;

[0040] Figure 14A This is a graph showing the bacterial growth of the rod-shaped nano zinc oxide aqueous solution in Example 1 after incubation with Escherichia coli for 24 hours.

[0041] Figure 14B The image shows the bacterial growth of Escherichia coli after incubating the aqueous solution of DXN-PT06 zinc oxide in Comparative Example 4 for 24 hours.

[0042] Figures 15A to 15D The image shows the SEM image of DXN-PT06 zinc oxide from Comparative Example 4. Detailed Implementation

[0043] The preferred embodiments of the present invention will be described in detail below. The accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0044] One embodiment of the present invention provides a method for preparing rod-shaped nano zinc oxide, comprising: reacting zinc salt with a precipitant to generate a precipitate under the action of a dispersant; wherein the dispersant includes polyvinylpyrrolidone (PVP) and a soluble chitosan derivative.

[0045] In one embodiment, the precipitate formed by the reaction of zinc salt and precipitant is zinc hydroxide, which decomposes into zinc oxide.

[0046] In one embodiment, the weight-average molecular weight of polyvinylpyrrolidone can be 50,000 to 1,000,000, such as 50,000, 55,000, 58,000, 60,000, 80,000, 100,000, 200,000, 500,000, 1,000,000, etc.

[0047] In one embodiment, the soluble chitosan derivative can be one or more of carboxymethyl chitosan and chitosan quaternary ammonium salts. The chitosan quaternary ammonium salt can be hydroxypropyltrimethylammonium chloride chitosan or chitosan hydrochloride. The weight-average molecular weight of the soluble chitosan derivative can be 100,000 to 300,000, for example, 110,000, 120,000, 150,000, 180,000, 200,000, 220,000, 250,000, 280,000, or 300,000.

[0048] In one embodiment, the mass ratio of polyvinylpyrrolidone to soluble chitosan derivative is (1-3):(1-3), and can further be (0.8-1.2):1, for example 0.5:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1.

[0049] In one embodiment, the zinc salt may be one or more of zinc acetate, zinc chloride, zinc nitrate, and zinc sulfate.

[0050] In one embodiment, the precipitant can be ammonia water, and the molar ratio of ammonia water to zinc salt in the ammonia water is (4-6):1, or more specifically (3-5):1.

[0051] In one embodiment, the mass ratio of zinc salt to soluble chitosan derivative is 2:(1-3), for example 2:1.2, 2:1.5, 2:1.8, 1:1, 2:2.2, 2:2.5, 2:2.8.

[0052] The method for preparing rod-shaped nano-zinc oxide according to one embodiment of the present invention includes:

[0053] Provided is a mixture comprising a zinc salt, polyvinylpyrrolidone, a soluble chitosan derivative, and water; and

[0054] A precipitant is added to the mixture to obtain a precipitate.

[0055] In one embodiment, the sum of the masses of polyvinylpyrrolidone and the soluble chitosan derivative accounts for 0.5% to 1% of the mass of the mixture, for example, 0.6%, 0.7%, 0.8%, or 0.9%.

[0056] In one embodiment, the concentration of zinc salt in the mixture is 0.01 to 0.1 mol / L, for example, 0.02 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, or 0.08 mol / L.

[0057] In one embodiment, ammonia water, a precipitant, can be added dropwise to the mixture over a period of 10 to 30 minutes, such as 12 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, or 28 minutes. After the addition is complete, the system can be stirred and reacted for another 2 hours.

[0058] In one embodiment, the precipitate obtained after the reaction is washed with ethanol and water respectively, and then dried. The resulting precipitate is the nano zinc oxide product.

[0059] In the preparation method of rod-shaped nano zinc oxide according to one embodiment of the present invention, two chemical reactions are involved: a reaction in which zinc salt reacts with a precipitant to form zinc hydroxide precipitate, and a reaction in which zinc hydroxide decomposes to form zinc oxide. The temperature for the precipitate formation reaction is 20–30°C, for example, 22°C, 25°C, 26°C, or 28°C; the reaction time is 1–3 hours, for example, 1.2 hours, 1.5 hours, or 1.8 hours. The temperature for the zinc hydroxide decomposition reaction (or the drying temperature) is 60–180°C, for example, 70°C, 80°C, 100°C, 120°C, 150°C, or 160°C; the reaction time (or the drying time) is 6–24 hours, for example, 8 hours, 10 hours, 12 hours, 15 hours, 16 hours, 18 hours, 20 hours, or 22 hours.

[0060] An embodiment of the present invention further provides a rod-shaped nano-zinc oxide prepared by the above method, which has a uniform morphology and particle size, and is hollow, making it easier to load reagents.

[0061] In one embodiment, the length of the rod-shaped nano zinc oxide is 300-1000 nm, such as 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, etc.; the cross-sectional diameter is 50-100 nm, such as 60 nm, 70 nm, 80 nm, 90 nm, etc.

[0062] The rod-shaped nano zinc oxide prepared according to one embodiment of the present invention has a soluble chitosan derivative attached to its surface, which makes the nano zinc oxide have good dispersibility in water and is beneficial for mixing with other materials.

[0063] The method for preparing rod-shaped nano zinc oxide according to one embodiment of the present invention is simple in steps, does not require high-temperature hydrothermal treatment or calcination, and can obtain rod-shaped nano zinc oxide with uniform morphology without the addition of complex morphology control agents. At the same time, the product is easy to clean.

[0064] The preparation of rod-shaped nano zinc oxide according to an embodiment of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. The soluble chitosan derivative (chitosan quaternary ammonium salt) used is hydroxypropyltrimethylammonium chloride chitosan purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Specifically, the hydroxypropyltrimethylammonium chloride chitosan of Example 1 has an average molecular weight of 100,000 to 200,000 and a degree of substitution of 98%; the hydroxypropyltrimethylammonium chloride chitosan of Example 4 has an average molecular weight of 200,000 to 300,000 and a degree of substitution of 98%; and the weight-average molecular weight of polyvinylpyrrolidone (PVP) is 58,000.

[0065] Example 1

[0066] 2.75g of zinc acetate dihydrate powder was added to 200mL of water to prepare a zinc acetate salt solution; 1.25g of PVP was dissolved in 25mL of ultrapure water to prepare a PVP solution; 1.25g of chitosan quaternary ammonium salt was dissolved in 25mL of ultrapure water to prepare a chitosan quaternary ammonium salt solution.

[0067] Add the above PVP solution and chitosan quaternary ammonium salt solution to the zinc acetate salt solution, stir magnetically for 5 minutes to mix evenly, and prepare a mixed solution with a zinc acetate concentration of 0.05M; then add 30.8 mL of 25% ammonia water dropwise to the mixed solution over a period of 15 minutes, and continue stirring for 2 hours after the addition is complete.

[0068] After the reaction was completed, the supernatant was removed by centrifugation, and the precipitate was washed twice with ethanol and ultrapure water, respectively. Finally, the precipitate was dried in an oven at 60°C for 12 hours to obtain rod-shaped nano zinc oxide.

[0069] Application examples

[0070] 1. Preparation of bacterial suspension

[0071] Pick one or two standard bacterial strains cultured by streak plating with an inoculation loop, inoculate them into prepared MH broth medium (purchased from Guangdong Huankai Microbial Technology Co., Ltd.), stir gently, seal the centrifuge tube containing the medium with sealing film, and place it in a 36℃ constant temperature shaking incubator for 24 hours to obtain a bacterial suspension.

[0072] Centrifuge the tube containing the bacterial suspension at 5000 rpm for 5 minutes. Discard the supernatant and wash twice with 10 ml of PBS solution. Add another 10 ml of PBS solution to prepare the bacterial suspension for use. Dilute the bacterial suspension with a certain amount of PBS solution, and add 200 μL to a 96-well plate. When the concentrations of Escherichia coli and Staphylococcus aureus are both around 0.1, the bacterial suspension has a concentration of 1*108 CFU / mL and should be used within 4 hours.

[0073] 2. Prepare zinc oxide aqueous solutions of different concentrations.

[0074] 10 mg of the nano-zinc oxide prepared in Example 1 was added to 10 ml of sterile water, shaken well, and sonicated at 210 W for 5 min to prepare an antibacterial solution with a concentration of 1000 μg / ml. Then, 2.5 ml of this solution was added to 2.5 ml of sterile water to prepare an antibacterial solution with a concentration of 500 μg / ml. Next, 2.5 ml of the 500 μg / ml antibacterial solution was added to 2.5 ml of sterile water to prepare a solution with a concentration of 250 μg / ml. Finally, 2.5 ml of the 250 μg / ml antibacterial solution was added to 2.5 ml of sterile water to prepare a solution with a concentration of 125 μg / ml.

[0075] 3. Inoculation solution

[0076] Add 2.5 mL of double-concentration nutrient broth (preparation method refers to the minimum inhibitory concentration test in "Disinfection Technical Specifications 2002") to the zinc oxide aqueous solutions of different concentrations in step 2. Set up a control group consisting of 2.5 mL of double-concentration nutrient broth and 2.5 mL of sterile water. Add 0.1 mL of the 1*10⁸ CFU / mL bacterial suspension prepared in step 1 to each of the above solutions. Seal the centrifuge tubes containing each group of samples with sealing film.

[0077] 4. Shaking cultivation

[0078] Place the centrifuge tubes containing the samples and bacterial culture into a 36°C constant temperature shaking incubator and incubate with shaking for 24 hours.

[0079] 5. Plate culture

[0080] Take 0.1 ml of the bacterial culture from step 4, after shaking and incubation for 24 hours, spread it onto nutrient agar medium, and incubate in a constant temperature and humidity incubator for 24 hours. Take photos to record the colony growth of each group. The results are as follows: Figure 5 As shown.

[0081] Bacterial survival rate was calculated based on the number of colonies on the plate, and the results are as follows: Figure 6 As shown. Wherein:

[0082] The formula for calculating bacterial survival rate is: Y = 1 - [(WQ) / W]

[0083] In the formula:

[0084] Y—Formula for calculating bacterial survival rate;

[0085] W—The concentration of viable bacteria (CFU / mL) in the conical flask after 24 hours of shaking contact with the control sample;

[0086] Q—The concentration of viable bacteria (CFU / mL) in the conical flask after 24 hours of shaking contact with the sample.

[0087] According to the Minimum Inhibitory Concentration (MIC) test (nutrient broth dilution method) in the "Disinfection Technical Specifications 2002", the MIC of the prepared nano zinc oxide was determined to be 125 ppm.

[0088] Example 2

[0089] This embodiment uses the same raw materials and steps as in Example 1 to prepare rod-shaped nano zinc oxide, the only difference being that the mass ratio of chitosan quaternary ammonium salt to PVP is 2:1, and the total amount of chitosan quaternary ammonium salt and PVP added is 1 wt%.

[0090] Example 3

[0091] This embodiment uses the same proportions and steps as Example 1 to prepare rod-shaped nano zinc oxide, the only difference being that the zinc salt used is zinc chloride.

[0092] Example 4

[0093] This embodiment uses the same raw materials and steps as Example 1 to prepare rod-shaped nano zinc oxide, the only difference being that the molecular weight of the chitosan quaternary ammonium salt used is 200,000 to 300,000.

[0094] Comparative Example 1

[0095] This example uses the same raw materials and steps as Example 1 to prepare nano zinc oxide, the only difference being that only PVP is used as a dispersant, and the amount of PVP added is 1 wt%.

[0096] Comparative Example 2

[0097] This example uses the same raw materials and steps as Example 1 to prepare nano zinc oxide, the only difference being that no dispersant is added during the preparation process, and instead 50 ml of ultrapure water is added to the reaction system.

[0098] Comparative Example 3

[0099] This example uses the same raw materials and steps as Example 1 to prepare nano zinc oxide, the only difference being that only chitosan quaternary ammonium salt is used as a dispersant, PVP is not added, and the amount of chitosan quaternary ammonium salt added is 1 wt%.

[0100] Comparative Example 4

[0101] The rod-shaped zinc oxide nanoparticles prepared in Example 1 and the purchased DXN-PT06 zinc oxide sample were respectively prepared into 250 μg / mL aqueous solutions. Their antibacterial properties were tested according to the method in Application Example 1. The test results are as follows: Figure 12A , 12B As shown.

[0102] The prepared rod-shaped zinc oxide nanoparticles were characterized, and the specific results are shown in [reference needed]. Figure 1AUp to 13B. Figures 1A to 1D The image shows a SEM image of the rod-shaped zinc oxide nanoparticles prepared in Example 1. As can be seen from the image, the zinc oxide nanoparticles are rod-shaped and hollow, with uniform morphology and a diameter of 50–100 nm.

[0103] Figure 2 , 3 The XRD pattern and UV spectrum of the rod-shaped zinc oxide nanoparticles from Example 1 are shown respectively. The results show that the prepared zinc oxide nanoparticles have a zincite structure.

[0104] Figure 4 The infrared spectrum of the rod-shaped zinc oxide nanoparticles from Example 1 is shown at 1583 cm⁻¹. -1 The peak appearing at 1453 cm⁻¹ is the amino stretching vibration peak of chitosan quaternary ammonium salt. -1 The presence of a strong absorption peak for the CH bending vibration of -CH3 indicates that the zinc oxide is loaded with chitosan quaternary ammonium salt.

[0105] The rod-shaped nano zinc oxide prepared in Example 1 (sample group) and the purchased rod-shaped nano zinc oxide (product from a nano zinc oxide manufacturer in Jiangsu) (control group) were dispersed in water, with the concentration of zinc oxide in both groups being 1000 μg / mL. The dispersion effect was as follows: Figures 7A to 7D As shown in the figure, after standing for 2 hours and 3 hours, the zinc oxide in the control group gradually settled. After standing for 24 hours, the zinc oxide in the control group had completely settled, while the zinc oxide in the sample group remained well dispersed. This indicates that the rod-shaped nano zinc oxide prepared in Example 1 has good dispersibility in water, which is beneficial for mixing with other materials.

[0106] Figure 8A , 8B The image shows a SEM image of the nano-zinc oxide from Example 2. It can be seen from the image that the product has no fixed morphology, and the particle size varies from 100 to 500 nm. Compared to Example 2, the rod-shaped nano-zinc oxide from Example 1 has more stable properties. Furthermore, the difference between Examples 1 and 2 shows that maintaining the mass ratio of chitosan quaternary ammonium salt to PVP at approximately 1:1 is more conducive to producing nano-zinc oxide with stable performance.

[0107] Figure 9 The image shows a SEM image of the nano zinc oxide from Example 3. As can be seen from the image, Example 3 uses zinc chloride as a zinc salt to synthesize nano zinc oxide similar to that of Example 1.

[0108] Figure 10 The image shows a SEM image of the nano zinc oxide from Example 4. As can be seen from the image, nano zinc oxide similar to that in Example 1 can also be synthesized using high molecular weight chitosan quaternary ammonium salt.

[0109] Figures 11A to 11DThe image shows a SEM image of the nano-zinc oxide from Comparative Example 1. As can be seen from the image, the prepared zinc oxide consists of large cubic particles with a radial length of approximately 1 μm and an axial length of approximately 2.5 μm. Compared to the rod-shaped nano-zinc oxide of Example 1, the zinc oxide prepared in Comparative Example 1 has a less uniform morphology and larger particle size.

[0110] Figures 12A to 12D The image shows a SEM image of the nano-zinc oxide from Comparative Example 2. As can be seen from the image, the prepared zinc oxide is mostly cuboid, mixed with particles of irregular morphology. Compared to the rod-shaped nano-zinc oxide of Example 1, the zinc oxide prepared in Comparative Example 2 has a less uniform morphology and larger particle size.

[0111] Figure 13A , 13B The image shows a SEM image of the zinc oxide nanoparticles in Comparative Example 3. As can be seen from the image, the prepared zinc oxide consists of coarse columnar particles with a particle size ranging from 2 μm to 5 μm. Compared to the rod-shaped zinc oxide nanoparticles in Example 1, the zinc oxide prepared in Comparative Example 3 exhibits a less uniform morphology and larger particle size.

[0112] Figure 14A , 14B The figures show the bacterial growth of *E. coli* after 24 hours of incubation with aqueous solutions of rod-shaped zinc oxide (Example 1) and DXN-PT06 zinc oxide. As can be seen from the figures, the DXN-PT06 zinc oxide sample at a concentration of 250 μg / mL could not completely inhibit the growth of *E. coli*, and no colonies grew on the rod-shaped zinc oxide plate from Example 1. This indicates that the rod-shaped zinc oxide sample prepared in Example 1 has a better antibacterial effect than the purchased DXN-PT06 rod-shaped zinc oxide sample. The SEM image of the DXN-PT06 rod-shaped zinc oxide is shown below. Figures 15A to 15D As shown.

[0113] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of preparing rod-like nanosized zinc oxide, comprising: A zinc salt reacts with a precipitant to form a precipitate under the action of a dispersant; wherein the dispersant includes polyvinylpyrrolidone and soluble chitosan derivatives, and the soluble chitosan derivatives include one or more of carboxymethyl chitosan and chitosan quaternary ammonium salts; The rod-shaped nano zinc oxide has a hollow structure, uniform morphology, a length of 300-1000 nm, and a cross-sectional diameter of 50-100 nm. A soluble chitosan derivative is attached to the surface of the zinc oxide. The preparation method includes the following specific steps: (1) Add the aqueous solution of polyvinylpyrrolidone and the aqueous solution of chitosan quaternary ammonium salt to the aqueous solution of zinc salt, and stir magnetically to obtain a mixed solution; (2) Add 25% ammonia water dropwise to the mixed solution as a precipitant, and continue stirring the reaction after the addition is complete; (3) The precipitate obtained from the reaction in step (2) is washed with ethanol and water respectively, and then dried. In step (1), the mass ratio of polyvinylpyrrolidone to the soluble chitosan derivative is 1:1, the mass ratio of zinc salt to the soluble chitosan derivative is 2:(1-3), and the concentration of zinc salt in the mixed solution is 0.01-0.1 mol / L. In step (2), the molar ratio of ammonia to zinc salt in ammonia water is (4-6):1, and the reaction temperature is 20-30℃.

2. The method of claim 1, wherein, The weight-average molecular weight of the polyvinylpyrrolidone is 50,000 to 1,000,000.

3. The method according to claim 1, wherein, The chitosan quaternary ammonium salt includes hydroxypropyltrimethylammonium chloride chitosan and chitosan hydrochloride; the weight-average molecular weight of the soluble chitosan derivative is 100,000 to 300,000.

4. The method according to claim 1, wherein, The zinc salt includes one or more of zinc acetate, zinc chloride, zinc nitrate, and zinc sulfate.

5. A rod-shaped nano zinc oxide, prepared by the method according to any one of claims 1 to 4.

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