CN102337030A - Polypyrrole compound nanosphere possessing electromagnetic function and its preparation method - Google Patents

Abstract

A polypyrrole/γ-Fe ₂ O ₃ composite nanosphere with electromagnetic function, which has a spherical shape, a particle size of 50-290nm, an electrical conductivity of 39.56S/cm-66.7S/cm, and a saturation magnetization of It is 0.658emu/g～5.85emu/g. During preparation, first add pyrrole to ammonia solution, then add ferrous chloride aqueous solution, and then add ferric chloride solution dropwise under stirring, then add dopant aqueous solution, the molar ratio of the dopant to pyrrole is 0.001-3 : 1, and control the reaction temperature at 0-5°C, electromagnetically stir the reaction to produce a black-green precipitate; filter the precipitate, wash it with distilled water, ethanol and ether in sequence, and dry it in vacuum. Through the addition of dopant, the present invention not only realizes high electric performance, but also realizes synchronous growth of electric and magnetic performance, and simultaneously reaches the maximum value; the preparation method is easy to operate, and mass production can be realized.

Description

A polypyrrole composite nanosphere with electromagnetic function and preparation method thereof

technical field

The invention belongs to the technical field of nanometer materials, and in particular relates to a polypyrrole/γ- _Fe2O3 composite nanosphere with electromagnetic function that can be used as a wave-absorbing material and a preparation _method thereof.

Background technique

Conductive polymer composites with both electrical and magnetic functions have special optical, electrical, and magnetic properties, and have potential applications in electromagnetic shielding, electrochromic devices, microwave absorption, and nonlinear optics. In recent years, electromagnetically functionalized micro-nanostructure conductive polymer materials have become a research hotspot in the field of conductive polymer micro-nano materials. Recently, electromagnetically functionalized micro/nanostructured conductive polymer composites have been successfully synthesized, such as polyaniline/ _Fe3O4 nanotubes (Zhang, _ZM ; Wan, MXSynth. Met. 2003, 132, 205.) , Polyaniline/γ-Fe ₂ O ₃ nanowires (Zhang, ZM; Wan, MX; Wei, Y. Nanotechnology 2005, 16, 2827.). The preparation of these two electromagnetically functionalized micro/nanostructured conductive polymer composites requires a two-step reaction to complete, that is, the magnetic nanoparticles such as Fe ₃ O ₄ or γ-Fe ₂ O ₃ nanoparticles are prepared in advance, and then In the presence of the prepared Fe ₃ O ₄ or γ-Fe ₂ O ₃ nanoparticles, a conductive polymer is generated, and an electromagnetically functionalized conductive polymer with a micro/nano structure is generated by a self-assembly method. However, this method easily leads to the problem of non-uniform dispersion of magnetic nanoparticles in the composite because the magnetic nanoparticles are easy to agglomerate. Recently, a "chemical one-step method" (Zhang, ZM; Deng, JY; Shen, JY; Wan, MX; Chen, ZJMacromol. The one-step generation of particles overcomes the defects of the above-mentioned two-step method. The preparation method of "chemical one-step method" is as follows:

1) Add 0.2mL of aniline to 10mL of ammonia solution (1M), and ultrasonically disperse to form a white homogeneous solution.

2) Add a certain amount of FeCl ₂ .4H ₂ O (10 mg, 20 mg, 30 mg, 40 mg) into 5 mL of distilled water, dissolve it completely and pour it into the aniline solution. 10 mL of an aqueous solution of FeCl ₃ .6H ₂ O (1.08 g, 3.24 g, 5.4 g, 8.1 g, 10.8 g, and 16.2 g of FeCl ₃ .6H ₂ O, respectively) was then added dropwise to the aniline solution. The pH values of the reaction solution before and after the dropwise addition were 10 and 2, respectively.

3) The electromagnetic stirring reaction at room temperature was completed after 12 hours.

4) The product was centrifuged (30 rpm, 5 min), washed three times with distilled water, ethanol and ether, and then vacuum-dried to obtain electromagnetically functionalized polyaniline/γ-Fe ₂ O ₃ composite nanowires.

However, regardless of the above-mentioned two-step method or the "chemical one-step method", the electrical conductivity of the obtained electromagnetically functionalized conductive polymer composite is relatively low (10 ^-2 ~ 100 S/cm). Although, polypyrrole/FeooH composite nanospheres (Xiao, HM; Zhang, W. D.; Fu, SY Composites Science and Technology 2010, 70, 909) with high electrical conductivity (16.1S/cm) have been reported, but their saturation magnetization The strength is only 0.11emu/g. So far, the electrical and magnetic properties of electromagnetically functionalized conductive polymer composites cannot be balanced.

Contents of the invention

The purpose of the present invention is to provide a polypyrrole/γFe ₂ O ₃ composite nanosphere with electromagnetic function and its preparation method, which can overcome the shortcomings of low electrical conductivity and inability to balance electrical and magnetic properties in the prior art .

A polypyrrole/γFe ₂ O ₃ composite nanosphere with electromagnetic functions, characterized in that the composite nanosphere has a spherical shape, a particle size of 50-290nm, and an electrical conductivity of 39.56S/cm-66.7S /cm, the saturation magnetization is 0.658emu/g～5.85emu/g.

The above-mentioned preparation method of the polypyrrole/γ- _{Fe2O3 composite} nanosphere with electromagnetic function is characterized in that pyrrole is first added to the ammonia solution with a concentration of (0.8-1.2) mol/L, ultrasonically forms a white emulsion, and then Add (8-10)mL ferrous chloride aqueous solution with a concentration of (0.0168-0.0699) mol/L to the white emulsion to obtain a solution containing ferrous chloride, stir it in an ice-water bath, and dissolve it in 15-30 minutes Into the above-mentioned ferrous chloride-containing solution, add dropwise an aqueous ferric chloride solution with a concentration of (0.5-0.6) mol/L, and add a dopant aqueous solution after the dropwise addition, and the molar ratio of the dopant to pyrrole is 0.001- 3:1, after adding the dopant aqueous solution, control the reaction temperature at 0-5°C, and react with electromagnetic stirring for 10-12 hours to produce a black-green precipitate; finally filter out the black-green precipitate, and use 8-10ml of distilled water and ethanol in sequence After washing with ether and drying in vacuum, polypyrrole/γ-Fe ₂ O ₃ composite nanospheres were obtained.

The invention overcomes the defects of non-uniform dispersion of magnetic particles, low electrical conductivity of the compound and incompatibility of electrical and magnetic properties existing in the traditional method. Through the addition of dopants, the electrical properties of the product are greatly improved, and the electrical conductivity can be increased by 10 ³ to 60 times; while achieving high electrical properties, the simultaneous growth of electrical and magnetic properties is achieved through the control of the amount of ferrous chloride , and reach the maximum value at the same time; the preparation method is simple to operate and can realize mass production.

Description of drawings

Fig. 1 is a scanning electron micrograph of polypyrrole/γ-Fe ₂ O ₃ composite nanospheres prepared in Example 1 of the present invention.

Fig. 2 is a scanning electron micrograph of polypyrrole/γ-Fe ₂ O ₃ composite nanospheres prepared in Example 2 of the present invention.

Fig. 3 is an X-diffraction pattern of polypyrrole/γ-Fe ₂ O ₃ composite nanospheres prepared in Examples 1 and 2 of the present invention.

Figure 4 is the hysteresis loop of polypyrrole/γ-Fe ₂ O ₃ composite nanospheres (amount of FeCl ₂ a: 30 mg; b: 75 mg; c: 100 mg; d: 125 mg).

Detailed ways

The polypyrrole/γ-Fe ₂ O ₃ composite nanosphere with electromagnetic function of the present invention is characterized in that the shape of the composite nanosphere is spherical, the particle diameter is 50-290nm, and the electrical conductivity is 39.56S/cm ～66.7S/cm, the saturation magnetization is 0.658emu/g～5.85emu/g. When preparing, first add pyrrole to the ammonia solution with a concentration of (0.8-1.2) mol/L, ultrasonically form a white emulsion, and then add (8-10) mL of ammonia solution with a concentration of (0.0168-0.0699) mol/L to the white emulsion. ferrous chloride aqueous solution to obtain a solution containing ferrous chloride, stirred under ice-water bath conditions, and added dropwise to the solution containing ferrous chloride with a concentration of (0.5 to 0.6) mol/L within 15 to 30 minutes. ferric chloride aqueous solution, add dopant aqueous solution after dropwise addition, the molar ratio of this dopant and pyrrole is 0.001～3:1, after adding dopant aqueous solution, control reaction temperature at 0～5 ℃, electromagnetic Stir the reaction for 10-12 hours to produce a black-green precipitate; finally filter out the black-green precipitate, wash with 8-10ml of distilled water, ethanol and ether, and then vacuum-dry to obtain polypyrrole/γ-Fe ₂ O ₃ composite nanospheres .

Example 1

1) adding pyrrole to ammonia solution with a concentration of 1 mol/L, and ultrasonically forming a white emulsion, wherein the volume ratio of pyrrole to ammonia solution is 0.0133;

2) Add 10 mL of ferrous chloride solution with a concentration of 0.0168 mol/L to the above solution;

3) Under ice-water bath conditions, under stirring, in 20 minutes, add ferric chloride solution with a concentration of 0.599mol/L to the solution obtained in the above step 2) within 20 minutes, and add p-toluenesulfonic acid solution after the addition is completed , wherein the molar ratio of p-toluenesulfonic acid to pyrrole is 2, after the p-toluenesulfonic acid solution is added, the reaction temperature is controlled at 0-5°C, the reaction is carried out under electromagnetic stirring for 12 hours, and a black-green precipitate is obtained;

4) The precipitate obtained in the above step 3) was filtered, washed with 10ml of distilled water, ethanol and ether in sequence, and then vacuum-dried to obtain polypyrrole/γ-Fe ₂ O ₃ composite nanospheres with electromagnetic functions.

Fig. 1 shows the scanning electron micrograph of the electromagnetically functionalized polypyrrole/γ-Fe ₂ O ₃ composite nanosphere prepared in Example 1 of the present invention. It can be seen from the figure that the particle size of the polypyrrole/γ-Fe ₂ O ₃ composite nanosphere is uniform, the average diameter is about 260nm, the electrical conductivity is 42.86S/cm, and the saturation magnetization is 0.958emu/g. Its structure was analyzed by X-ray diffraction, as shown in FIG. 3 . In addition to the characteristic peaks attributed to polypyrrole appearing at 2θ=25.1°, multiple diffraction peaks appear at 2θ=30.4°, 35.7°, 43.4°, 53.8°, 57.3° and 62.9°, and these diffraction peaks are consistent with the standard The diffraction peaks are completely consistent, which proves that the polypyrrole/γ-Fe ₂ O ₃ composite nanospheres are successfully prepared by the preparation method of the present invention.

Test of absorbing performance:

The absorption effect of electromagnetic waves in the three frequency bands of 1～18GHz, 18～26.5GHz and 26.5～40GHz is measured respectively by arch bridge antenna method, and the measurement results show that the absorption attenuation of the material prepared in this embodiment is at 7～16GHz and 26～40GHz The values are all over -5dB, and the absorption attenuation values at 8-12GHz and 28-35GHz are above -10dB, and the maximum absorption attenuation can reach -11dB in the wave frequency range of 1-18GHz, which shows that the material obtained in this example It has a good absorption effect on electromagnetic waves in a wide frequency band.

Example 2

1) adding pyrrole to the aqueous ammonia solution with a concentration of 0.96mol/L, and ultrasonically forming a white emulsion, wherein the volume ratio of pyrrole to the aqueous ammonia solution is 0.0135;

2) Add 10 mL of ferrous chloride solution with a concentration of 0.0559 mol/L to the above solution;

3) Under ice-water bath conditions, under stirring, in 20 minutes, in the solution that above-mentioned step 2) obtains, dropwise add concentration and be 0.585mol/L ferric chloride solution, add p-toluenesulfonic acid solution after dropwise addition, Wherein the molar ratio of p-toluenesulfonic acid to pyrrole is 1.8, after the p-toluenesulfonic acid solution is added, the reaction temperature is controlled at 0-5°C, and the reaction is electromagnetically stirred for 11 hours to obtain a black-green precipitate;

4) The precipitate obtained in the above step 3) was filtered, washed three times with 9ml of distilled water, ethanol and ether, and then vacuum-dried to obtain electromagnetically functionalized polypyrrole/γ-Fe ₂ O ₃ composite nanospheres.

Figure 2 shows the scanning electron micrograph of the polypyrrole/γ-Fe ₂ O ₃ composite nanosphere with electromagnetic function prepared in Example 2 of the present invention, its average diameter is about 80nm, the conductivity is 64.4S/cm, and the saturation magnetization The strength is 4.85emu/g. Its structure was analyzed by X-ray diffraction, as shown in FIG. 3 . In addition to the characteristic peaks at 2θ=25.1° attributed to polypyrrole/γ-Fe ₂ O ₃ , multiple diffraction peaks appeared at 2θ=30.4°, 35.7°, 43.4°, 53.8°, 57.3° and 62.9° , these diffraction peaks are completely consistent with the standard diffraction peaks, which proves that polypyrrole/γ-Fe ₂ O ₃ composite nanospheres are successfully prepared by the preparation method of the present invention.

Test of absorbing performance:

The absorption effect of electromagnetic waves in the three frequency bands of 1～18GHz, 18～26.5GHz, and 26.5～40GHz is measured by the arch bridge antenna method, and the measurement results show that the absorption attenuation of the material prepared in this embodiment is at 6～18GHz and 24～40GHz. The values are all over -5dB, and the absorption attenuation values at 10-15GHz and 27-36GHz are above -10dB, and the maximum absorption attenuation value can reach -12dB in the wave frequency range of 1-18GHz, which shows that the The material has a good absorption effect on electromagnetic waves in a wide frequency band.

Example 3

1) adding pyrrole to ammonia solution with a concentration of 1 mol/L, and ultrasonically forming a white emulsion, wherein the volume ratio of pyrrole to ammonia solution is 0.0133;

2) Add 10 mL of ferrous chloride solution with a concentration of 0.0559 mol/L to the above solution;

3) Under ice-water bath conditions, under stirring, in 20 minutes, add ferric chloride solution with a concentration of 0.600mol/L dropwise to the solution obtained in the above step 2) within 20 minutes, and add phosphoric acid solution after the dropwise addition, wherein phosphoric acid The molar ratio to pyrrole is 2.1. After the phosphoric acid solution is added, the reaction temperature is controlled at 0-5°C, and the reaction is electromagnetically stirred for 12 hours to obtain a black-green precipitate;

4) The precipitate obtained in the above step 3) was filtered, washed three times with 10 ml of distilled water, ethanol and ether, and then vacuum-dried to obtain electromagnetically functionalized polypyrrole/γ-Fe ₂ O ₃ composite nanospheres. Scanning electron microscopy and X-ray diffraction proved that polypyrrole/γ-Fe ₂ O ₃ composite nanospheres were successfully prepared.

Test of absorbing performance:

The absorption effect of electromagnetic waves in the three frequency bands of 1～18GHz, 18～26.5GHz and 26.5～40GHz is measured respectively by arch bridge antenna method. The measurement results show that the absorption attenuation of the material prepared in this embodiment is at 8～17GHz and 25～38GHz. The values are all over -5dB, and the absorption attenuation values at 9-13GHz and 29-37GHz are above -10dB, and the maximum absorption attenuation value can reach -9dB in the wave frequency range of 1-18GHz, which shows that the The material has a good absorption effect on electromagnetic waves in a wide frequency band.

The volume ratio of the pyrrole to the ammonia solution in the present invention is 0.0102-0.0145:1. The dopant is p-toluenesulfonic acid, phosphoric acid, acetic acid or trifluoroacetic acid.

Claims (4)

1. polypyrrole/γ-Fe with function solenoid ₂O ₃The mixture nanometer ball, the pattern that it is characterized in that this mixture nanometer ball is a spheroidal, and particle diameter is 50～290nm, and specific conductivity is 39.56S/cm～66.7S/cm, and saturation magnetization is 0.658emu/g～5.85emu/g.

2. the described polypyrrole/γ-Fe of claim 1 with function solenoid ₂O ₃The preparation method of mixture nanometer ball is characterized in that at first adding the pyrroles, ultrasonic formation white emulsion to concentration in the ammonia soln of (0.8～1.2) mol/L; In this white emulsion, adding (8～10) mL concentration afterwards is the ferrous chloride aqueous solution of (0.0168～0.0699) mol/L; Obtain containing chlorination ferrous solution, under the ice-water bath condition, stir, dripped the ferric chloride in aqueous solution of concentration for (0.5～0.6) mol/L introversive above-mentioned containing in the chlorination ferrous solution at 15～30 minutes; Dropwise the back and add the doping agent aqueous solution; This doping agent and pyrroles's mol ratio is 0.001～3: 1, and after the interpolation of the doping agent aqueous solution finished, control reaction temperature was at 0～5 ℃; Induction stirring reaction 10～12 hours produces the blackish green deposition; Leach the blackish green deposition at last, with 8～10ml zero(ppm) water, ethanol and the oven dry of ether washing final vacuum, obtain polypyrrole/γ-Fe successively ₂O ₃The mixture nanometer ball.

3. polypyrrole/the γ of function solenoid as claimed in claim 2-Fe ₂O ₃The preparation method of mixture nanometer ball, the volume ratio that it is characterized in that described pyrroles and ammonia soln is 0.0102～0.0145: 1.

4. polypyrrole/the γ of function solenoid as claimed in claim 2-Fe ₂O ₃The preparation method of mixture nanometer ball is characterized in that described doping agent is tosic acid, phosphoric acid, acetate or trifluoroacetic acid.

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