Preparation method and application of hollow ferroferric oxide nanospheres coated with polypyrrole self-assembled nanorods

Abstract

The application relates to a preparation method and application of a kind of polypyrrole-coated hollow ferroferric oxide nanosphere self-assembled nanorod, and belongs to the technical field of wave-absorbing materials.The one-dimensional nanorod composite material is prepared by taking hollow Fe3O4 nanosphere as a core layer and polypyrrole (PPy) as a shell layer through self-assembly.The hollow structure of the Fe3O4 nanosphere greatly reduces the weight of the material.The PPy-coated Fe3O4 nanosphere is self-assembled into a one-dimensional structure under a magnetic field, and a conductive network is effectively formed among the one-dimensional nanorods, the dielectric loss of the material is improved, the material has good wave-absorbing performance under low filling amount, and the density of the wave-absorbing material is reduced.The polypyrrole-coated hollow ferroferric oxide nanosphere is used as an electromagnetic wave absorbing material.The application has good application prospect in the field of wave absorption, and can also expand the application in the field of supercapacitors.

Description

Technical Field

[0001] This invention belongs to the field of microwave absorbing materials technology, specifically relating to a method for preparing and applying a self-assembled nanorod of polypyrrole-coated hollow iron oxide nanospheres. Background Technology

[0002] Electromagnetic wave absorbing materials can absorb the energy of incident electromagnetic waves and convert it into heat or other forms of energy, reducing the intensity of electromagnetic waves and providing an effective and feasible method for solving problems such as electromagnetic radiation and interference. An ideal absorbing material should simultaneously possess four properties: thinness, lightness, wide absorption bandwidth, and strong absorption capacity. To achieve these properties, magnetic materials are often used in combination with dielectric materials to achieve impedance matching, thereby enabling the material to absorb electromagnetic waves across a wide frequency range. Magnetic materials mainly include magnetic metals and their alloy powders, ferrites, etc. Magnetic absorbing materials have high saturation magnetization, giving them a significant advantage in electromagnetic wave absorption. However, their absorption mechanism is singular, and their absorption bandwidth is narrow. Therefore, magnetic materials are often combined with conductive polymers as dielectric materials to optimize the material's absorption performance. Conductive polymers are polymer materials with a conjugated electron system in their main chain, which can be varied by doping within the range of insulators, semiconductors, and conductors. Due to their high conductivity, conductive polymer materials can be used in the field of wave absorption, with their loss mechanism being conductive loss. Common conductive polymers for wave absorption include polyaniline and polypyrrole.

[0003] Since magnetic materials are generally metallic iron, cobalt, nickel and their oxides, they have a high density and require a high filling amount to achieve certain wave absorption performance. This results in a high overall density of the wave absorbing material, which is not conducive to practical applications. Summary of the Invention

[0004] To overcome the shortcomings of existing materials, this invention provides a method for preparing and applying polypyrrole-coated hollow iron oxide nanospheres self-assembled into nanorods.

[0005] This invention utilizes hollow Fe3O4 nanospheres as the core layer and polypyrrole (PPy) as the shell layer to prepare a one-dimensional nanorod composite material through self-assembly. The hollow structure of the Fe3O4 nanospheres significantly reduces the material weight. By self-assembling PPy-coated Fe3O4 nanospheres under a magnetic field to form a one-dimensional structure, and through the interlocking of the one-dimensional nanorods, a conductive network can be effectively formed in the material, improving the dielectric loss and enabling it to exhibit good microwave absorption performance with low filling amounts, thereby reducing the density of the microwave absorbing material.

[0006] A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres is specifically carried out according to the following steps:

[0007] 1. Hollow Fe3O4 nanospheres are added to deionized water and then dispersed evenly by ultrasonic or mechanical stirring to obtain suspension A;

[0008] 2. Add pyrrole monomer to suspension A, and then disperse it evenly by ultrasonic or mechanical stirring to obtain suspension B;

[0009] 3. Stir suspension B magnetically at room temperature for a period of time to obtain suspension C;

[0010] 4. Dissolve the oxidant in deionized water, and then add it to suspension C under ice bath and magnetic stirring conditions to obtain suspension D;

[0011] 5. The suspension D was reacted for a period of time under ice bath and magnetic stirring conditions to obtain a precipitate.

[0012] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0013] A self-assembled nanorod of polypyrrole-coated hollow iron oxide nanospheres is used as an electromagnetic wave absorbing material.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The raw materials used in this invention, such as pyrrole and Fe3O4, are readily available, and the product preparation method is simple and reliable. The prepared one-dimensional nanorod composite material has a stable structure and controllable morphology, and can effectively form a conductive network within the material, giving it good microwave absorption performance even with lower filling amounts. It has promising applications in the field of microwave absorption and can also be used to expand its applications in fields such as supercapacitors. Attached Figure Description

[0016] Figure 1 The image shows a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 1, magnified 2.10 kilometres.

[0017] Figure 2 The electromagnetic wave absorption performance of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 1 is shown in the figure.

[0018] Figure 3 SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 2, magnified 2.10 kilometres;

[0019] Figure 4 The image shows SEM images of hollow Fe3O4 nanospheres with a particle size of approximately 250 nm as described in Examples 1-4, magnified to 100.00 thousand times.

[0020] Figure 5 The image shows a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 2.10 kilometres.

[0021] Figure 6 The electromagnetic wave absorption performance of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3 is shown in the figure.

[0022] Figure 7 The image shown is a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 5.00 kilometres.

[0023] Figure 8 The image shows the nitrogen distribution of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 5.00 kilofold.

[0024] Figure 9 The image shown is a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 4, magnified 2.10 kilometres. Detailed Implementation

[0025] Specific Implementation Method 1: This implementation method describes a method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, which is specifically completed according to the following steps:

[0026] 1. Hollow Fe3O4 nanospheres are added to deionized water and then dispersed evenly by ultrasonic or mechanical stirring to obtain suspension A;

[0027] 2. Add pyrrole monomer to suspension A, and then disperse it evenly by ultrasonic or mechanical stirring to obtain suspension B;

[0028] 3. Stir suspension B magnetically at room temperature for a period of time to obtain suspension C;

[0029] 4. Dissolve the oxidant in deionized water, and then add it to suspension C under ice bath and magnetic stirring conditions to obtain suspension D;

[0030] 5. The suspension D was reacted for a period of time under ice bath and magnetic stirring conditions to obtain a precipitate.

[0031] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0032] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the particle size of the hollow Fe3O4 nanospheres mentioned in step one is 200nm to 1000nm. The other steps are the same as in Specific Implementation Method One.

[0033] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the concentration of hollow Fe3O4 nanospheres in suspension A mentioned in step one is 0.000625 g / mL to 0.05 g / mL. The other steps are the same as in Specific Implementation Method One or Two.

[0034] Specific Implementation Method Four: The difference between this implementation method and Specific Implementation Methods One to Three is that the mass ratio of the pyrrole monomer to the hollow Fe3O4 nanospheres in suspension A in step two is (0.5-5):1. The other steps are the same as in Specific Implementation Methods One to Three.

[0035] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the magnetic stirring time in step three is 0h to 12h. The other steps are the same as in Specific Implementation Methods One to Four.

[0036] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the oxidant mentioned in step four is ammonium persulfate, ferric chloride, or ferric chloride hexahydrate. The other steps are the same as in Specific Implementation Methods One to Five.

[0037] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the mass ratio of the oxidant to the pyrrole monomer in suspension C in step four is (0.5-5):1; the mass ratio of the oxidant to the volume of deionized water in step four is (0.33g-3.3g):(5mL-200mL). The other steps are the same as in Specific Implementation Methods One to Six.

[0038] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the magnetic stirring speed in step four is 100 rpm to 1000 rpm. The other steps are the same as in Specific Implementation Methods One to Seven.

[0039] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the magnetic stirring speed in step five is 100 rpm to 1000 rpm, and the magnetic stirring time is 0.5 h to 24 h. The other steps are the same as in Specific Implementation Methods One to Eight.

[0040] Specific Implementation Method 10: This implementation method is a self-assembled nanorod of polypyrrole-coated hollow iron oxide nanospheres as an electromagnetic wave absorbing material.

[0041] The beneficial effects of the present invention are verified using the following embodiments:

[0042] Example 1: A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, specifically completed according to the following steps:

[0043] 1. Add 0.1g of hollow Fe3O4 nanospheres with a particle size of approximately 250nm to 80mL of deionized water, and then disperse them evenly by ultrasound to obtain suspension A;

[0044] 2. Add 0.1g of pyrrole monomer to suspension A, and then disperse it evenly by sonication to obtain suspension B;

[0045] 3. Stir suspension B magnetically at room temperature and 400 rpm for 2 hours to obtain suspension C;

[0046] 4. Dissolve 0.33g of ammonium persulfate in 20mL of deionized water, and then add it to suspension C under ice bath and magnetic stirring at 400rpm to obtain suspension D;

[0047] 5. The suspension D was reacted in an ice bath with magnetic stirring at 400 rpm for 6 hours to obtain the precipitate.

[0048] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0049] Figure 1 The image shows a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 1, magnified 2.10 kilometres.

[0050] from Figure 1 The material clearly exhibits a rod-like structure, formed by the self-assembly of hollow Fe3O4 nanospheres.

[0051] Microwave absorption performance testing method: The sample and paraffin were mixed evenly at a 1:1 mass ratio and then compacted into a ring with an outer diameter of 7.00 mm and an inner diameter of 3.04 mm. The dielectric constant and permeability of the sample in the range of 2–18 GHz were then tested using a vector network analyzer. Finally, the microwave absorption performance of the sample was calculated using transmission line theory.

[0052] Figure 2 The electromagnetic wave absorption performance of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 1 is shown in the figure.

[0053] from Figure 2 It can be seen that the polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods prepared in Example 1 have obvious wave absorption effect at low frequencies.

[0054] Example 2: A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, specifically completed according to the following steps:

[0055] 1. Add 0.1g of hollow Fe3O4 nanospheres with a particle size of approximately 250nm to 80mL of deionized water, and then disperse them evenly by ultrasound to obtain suspension A;

[0056] 2. Add 0.1g of pyrrole monomer to suspension A, and then disperse it evenly by sonication to obtain suspension B;

[0057] 3. Stir suspension B magnetically at room temperature and 800 rpm for 2 hours to obtain suspension C;

[0058] 4. Dissolve 0.33g of ammonium persulfate in 20mL of deionized water, and then add it to suspension C under ice bath and magnetic stirring at 800rpm to obtain suspension D;

[0059] 5. The suspension D was reacted in an ice bath with magnetic stirring at 800 rpm for 6 hours to obtain the precipitate.

[0060] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0061] Figure 3 SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 2, magnified 2.10 kilometres;

[0062] from Figure 3 It can be seen that the self-assembled nanorods were successfully prepared. Compared with Example 2, the content of self-assembled rod-shaped structures was relatively reduced in this example due to the larger magnetic stirring speed.

[0063] Example 3: A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, specifically completed according to the following steps:

[0064] 1. Add 0.1g of hollow Fe3O4 nanospheres with a particle size of approximately 250nm to 80mL of deionized water, and then disperse them evenly by ultrasound to obtain suspension A;

[0065] 2. Add 0.2g of pyrrole monomer to suspension A, and then disperse it evenly by sonication to obtain suspension B;

[0066] 3. Dissolve 0.66g of ammonium persulfate in 20mL of deionized water, and then add it to suspension B under ice bath and magnetic stirring at 400rpm to obtain suspension C.

[0067] 5. The suspension D was reacted in an ice bath with magnetic stirring at 400 rpm for 6 hours to obtain the precipitate.

[0068] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0069] Figure 5 The image shows a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 2.10 kilometres.

[0070] from Figure 5 It can be seen that the self-assembled nanorods were successfully prepared. Compared with Examples 1 and 2, the increased pyrrole content in this example promoted the self-assembly of the rod-shaped structure, resulting in a slight increase in the aspect ratio of the rod-shaped structure. There were also fewer scattered unassembled reactants.

[0071] Microwave absorption performance testing method: The sample and paraffin were mixed evenly at a 1:1 mass ratio and then compacted into a ring with an outer diameter of 7.00 mm and an inner diameter of 3.04 mm. The dielectric constant and permeability of the sample in the range of 2–18 GHz were then tested using a vector network analyzer. Finally, the microwave absorption performance of the sample was calculated using transmission line theory.

[0072] Figure 6 The electromagnetic wave absorption performance of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3 is shown in the figure.

[0073] from Figure 6 It can be seen that the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres exhibit significant high-frequency absorption effects. The effective absorption bandwidth is 3.12 GHz at a thickness of 1.5 mm and reaches 3.72 GHz at a thickness of 2 mm, achieving a wide absorption range even with relatively thin thicknesses.

[0074] Figure 7 The image shown is a SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 5.00 kilometres.

[0075] from Figure 7 It can be seen that the self-assembled nanorods were successfully prepared. The nanorods were formed by the self-assembly of hollow Fe3O4 nanospheres. The nanorods are approximately 16 μm in length and 3 μm in diameter.

[0076] Figure 8 The image shows the nitrogen distribution of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 3, magnified 5.00 kilofold.

[0077] from Figure 8 It can be seen that the nitrogen element is uniformly distributed on the surface of the nanorods, indicating that polypyrrole is uniformly coated on the surface of the iron oxide nanospheres.

[0078] Example 4: A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, specifically completed according to the following steps:

[0079] 1. Add 0.1g of hollow Fe3O4 nanospheres with a particle size of approximately 250nm to 80mL of deionized water, and then disperse them evenly by ultrasound to obtain suspension A;

[0080] 2. Add 0.2g of pyrrole monomer to suspension A, and then disperse it evenly by sonication to obtain suspension B;

[0081] 3. Stir suspension B magnetically at room temperature and 400 rpm for 2 hours to obtain suspension C;

[0082] 4. Dissolve 0.66g of ammonium persulfate in 20mL of deionized water, and then add it to suspension C under ice bath and magnetic stirring at 400rpm to obtain suspension D;

[0083] 5. The suspension D was reacted in an ice bath with magnetic stirring at 400 rpm for 6 hours to obtain the precipitate.

[0084] 6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

[0085] Figure 9 SEM image of the self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres prepared in Example 4, magnified 2.10 kilometres.

[0086] from Figure 9 It can be seen that the self-assembled nanorods were successfully prepared, but there were a lot of scattered unassembled reactants.

[0087] Figure 4 The image shows SEM images of hollow Fe3O4 nanospheres with a particle size of approximately 250 nm as described in Examples 1-4, magnified to 100.00 thousand times.

[0088] Figure 4 The hollow Fe3O4 nanospheres with a particle size of approximately 250 nm described in Examples 1-4 were commercially available. The nanospheres have a uniform particle size distribution of approximately 250 nm and are formed by the accumulation of smaller particles.

Claims

1. A method for preparing self-assembled nanorods of polypyrrole-coated hollow iron oxide nanospheres, characterized in that... The preparation method is specifically carried out according to the following steps:

1. Hollow Fe3O4 nanospheres are added to deionized water and then dispersed evenly by ultrasonic or mechanical stirring to obtain suspension A; The hollow Fe3O4 nanospheres mentioned in step one have a particle size of 200nm~1000nm; The concentration of hollow Fe3O4 nanospheres in suspension A mentioned in step one is 0.000625 g / mL to 0.05 g / mL; 2. Add pyrrole monomer to suspension A, and then disperse it evenly by ultrasonic or mechanical stirring to obtain suspension B; The mass ratio of the pyrrole monomer to the hollow Fe3O4 nanospheres in suspension A in step two is (0.5~5):1; 3. Stir suspension B magnetically at room temperature for a period of time to obtain suspension C; 4. Dissolve the oxidant in deionized water, and then add it to suspension C under ice bath and magnetic stirring conditions to obtain suspension D; The mass ratio of the oxidant to the pyrrole monomer in suspension C mentioned in step four is (0.5~5):1; 5. The suspension D was reacted for a period of time under ice bath and magnetic stirring conditions to obtain a precipitate.

6. The precipitate was subjected to magnetic separation, washing, and drying to obtain polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods.

2. The method for preparing polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods according to claim 1, characterized in that... The magnetic stirring time mentioned in step three is 0h~12h.

3. The method for preparing polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods according to claim 1, characterized in that... The oxidant mentioned in step four is ammonium persulfate, ferric chloride, or ferric chloride hexahydrate.

4. The method for preparing polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods according to claim 1, characterized in that... The mass ratio of the oxidant to the volume of deionized water in step four is (0.33g~3.3g):(5mL~200mL).

5. The method for preparing polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods according to claim 1, characterized in that... The magnetic stirring speed mentioned in step four is 100 rpm to 1000 rpm.

6. The method for preparing polypyrrole-coated hollow iron oxide nanospheres self-assembled nanorods according to claim 1, characterized in that... The magnetic stirring speed in step five is 100 rpm to 1000 rpm, and the magnetic stirring time is 0.5 h to 24 h.

7. The application of a self-assembled nanorod of polypyrrole-coated hollow iron oxide nanospheres prepared by the preparation method described in claim 1, characterized in that... A self-assembled nanorod of polypyrrole-coated hollow iron oxide nanospheres is used as an electromagnetic wave absorbing material.

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