CN105885043B - The preparation method of polyaniline nano microballoon with nucleocapsid - Google Patents

Abstract

The invention discloses a method for preparing polyaniline nano-microspheres with a core-shell structure. The steps include: preparing monodisperse polystyrene microspheres; nitrating the polystyrene microspheres to obtain nitrated polystyrene microspheres; Aminated polystyrene microspheres are obtained after reducing nitrated polystyrene microspheres; after aniline solution is obtained by dissolving aniline in a non-polar organic solvent, the acidic aqueous solution of aminated polystyrene microspheres and initiator is added dropwise into the above-mentioned aniline solution to react to obtain polyaniline nano-microspheres with a core-shell structure. The polyaniline nano microspheres with a core-shell structure obtained by the preparation method of the invention not only have good appearance and uniform size, but also have good monodispersity, good dispersibility in water, and are not easy to agglomerate. The preparation method of the invention is simple, the conditions are mild, there is no metal ion interference, the reproducibility is good, and the practicability is strong.

Description

Preparation method of polyaniline nano-microspheres with core-shell structure

technical field

The invention relates to the field of polymer materials, in particular to a method for preparing polyaniline nano-microspheres with a core-shell structure.

Background technique

Polyaniline (PANI for short) is an important conductive polymer in polymer materials, and occupies an important position in conjugated conductive polymer materials. PANI molecule is a linear conjugated polymer connected head to tail, its structure is composed of reduction unit (y unit) and oxidation unit (1-y unit), the y value in the formula is used to characterize the redox degree of PANI, in The oxidation unit contains a quinone structure, and different y values correspond to different structures, components, colors and conductivity. It can be seen from the structural formula that the transformation from an insulator to a conductor can be realized by introducing substituent groups on the molecular chain of PANI or introducing different ions through protonic acid doping; in addition, PANI is easy to obtain because of its monomer raw materials, simple synthesis process, and at the same time It also has the advantages of excellent physical properties and good environmental stability, so it has become a hot spot in the research of conductive polymer materials today.

An important application field of PANI is the electrode material, which is its unique conjugated system with good electron conductivity, and can change the energy level gap and ionization potential of the molecular chain through chemical modification, so that it can be used in the field of electrochemical supercapacitors . However, the polymers prepared by the general method have disadvantages such as easy agglomeration, small effective specific surface area, and poor stability, which affect the electrochemical performance of PANI. To overcome these shortcomings, it is the most direct way to increase the effective specific surface area and stability of PANI materials by controlling their morphology and structure. In recent years, research on the morphology of polyaniline has mainly focused on nanospheres (RSC Adv.2015,5,12034–12042), nanowires (J.Mater.Chem.A,2015,3,23307–23315), (J.Power Sources 2015,294,16–21), nanorods (J.Mater.Chem.2012,22,2774–2780) and nanotubes (J.Mater.Chem.A,2013,1,3315–3324 )Wait. Although polyaniline with these morphologies has good electrochemical properties, there are still some problems, such as the preparation process is more complicated, and the process route is not easy to control; the prepared PANI material can have better electrochemical properties only when it is combined with other materials. ; And problems such as poor water solubility.

In order to solve the above-mentioned technical problems, the synthesis of polyaniline microspheres has also become a focus of research this year. As the application number is 200710304102.2, the Chinese patent uses polystyrene (Polystyrene, be called for short PS) microspheres as a synthetic template, and ferric nitrate (Fe( NO ₃ ) ₃ ) and ferric chloride (FeCl ₃ ) were used as oxidants to invent polystyrene/polyaniline conductive polymer composite microspheres with core-shell structure. Although this technology can obtain polyaniline microspheres with better morphology Balls, but the introduction of metal elements will affect the electrochemical performance of the material. The Chinese patent with application number 201110403637.1 uses a mixed solution of water and ethanol to prepare a polyaniline nanosphere with a diameter of 50-200nm. Although a good shape can be obtained, the size distribution is not uniform and the water solubility is poor. . Huang Bin et al. (Functional Materials, 2011, 42(1), 144-147), used the template method to prepare PANI hollow microspheres with PS colloidal particles as microsphere cores, and applied them to ESC electrode materials. Its electrochemical performance in the field of energy storage, although this kind of hollow microsphere has good electrochemical performance, but from the picture of scanning electron microscope, there are still problems such as uneven size. The Chinese patent with application number 201510852325.7 synthesized sulfonated polystyrene/polyaniline composite microspheres with sulfonated polystyrene (SPS for short) as the core and polyaniline as the shell. Although the problem of water solubility was solved, the Poor conductivity.

Contents of the invention

The purpose of the present invention is to solve the problems of the prior art, and to provide a method for preparing polyaniline nanospheres with a core-shell structure. The polyaniline nanospheres with a core-shell structure prepared by this method are not only uniform in size, Moreover, it has good water dispersibility, stable structure and good conductivity. Described technical scheme is as follows:

A preparation method of polyaniline nano microspheres with a core-shell structure, the steps comprising:

(1) preparing monodisperse polystyrene microspheres;

(2) ultrasonically dispersing the polystyrene microspheres in step (1) into a nitrating reagent, reacting at 40-50° C. for 1-2 hours, washing and drying to obtain nitrated polystyrene microspheres;

(3) obtaining aminated polystyrene microspheres after reducing the nitrated polystyrene microspheres in step (2);

(4) after aniline is dissolved in the non-polar organic solvent to obtain the aniline solution, then the acidic aqueous solution containing the aminated polystyrene microspheres and the initiator described in the step (3) is added dropwise in the above-mentioned aniline solution, and the After the system is stable, react at -5-5° C. for 10-24 hours, purify and dry to obtain the polyaniline nano-microspheres with a core-shell structure.

The non-polar organic solvent is preferably chloroform.

Preferably, the polystyrene microspheres in the step (1) are prepared by soap-free emulsion polymerization. The specific preparation method can be adjusted according to the existing technology, for example, as described in the Chinese patent application number 201510852325.7 in the background technology.

Preferably, the nitrating reagent in the step (2) is a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2.

Preferably, the reduction in step (3) is obtained by reducing Na ₂ S ₂ O ₄ or sodium borohydride at 70-80°C for 2-5 hours.

Preferably, the initiator is ammonium persulfate.

Preferably, the acidic aqueous solution in the step (4) is an aqueous sulfuric acid or hydrochloric acid solution with a concentration of 0.5 mol/L.

Preferably, the purification in step (4) is obtained by adding acetone, filtering, and then washing with ethanol.

Preferably, the mass ratio of aminated polystyrene microspheres to aniline in the step (4) is 1:(1-4).

Preferably, the molar ratio of aniline to initiator in the step (4) is 1:(0.5-5), more preferably 1:1.

Preferably, the acidic aqueous solution in the step (4) also contains sodium dodecylsulfonate with a solute mass of 10-20%.

The present invention has utilized the method for interfacial polymerization, and during the polymerization of step (4), the upper layer is an aqueous phase solution, the lower layer is an organic phase solution, and the polymerization reaction occurs at the interface, because the synthesized polyaniline nano-microspheres have hydrophilicity, After formation, it diffuses to the water phase, resulting in a decrease in the concentration at the interface, and the reaction continues. Therefore, the morphology characteristics of polyaniline microspheres can be effectively controlled by simply adjusting the amount of aniline monomer and initiator, and a microsphere product with a more uniform size can be obtained. At the same time, adding sodium dodecyl sulfonate may be due to the fact that the hydrophilic chain extends into the water phase, and the hydrophobic chain extends into the organic phase to form curved micelles, which makes the polyaniline nanospheres difficult to agglomerate due to van der Waals force, thus playing a role. The role of stabilizing the reaction system.

The beneficial effects brought by the technical solution provided by the embodiments of the present invention are:

The polyaniline nano-microspheres with core-shell structure obtained by the preparation method of the present invention take aminated polystyrene as the core and polyaniline as the shell, not only have good appearance and uniform size, but also have good monodispersity and good dispersibility in water. Not easy to reunite. At the same time, each polyaniline-wrapped microsphere of the polyaniline nano-microsphere prepared by the present invention contains a number of aminated polystyrene, which increases its surface area. And the applicant creatively found that the polystyrene modified by amination can increase the hydrophilicity and conductivity, and the amino group can also perform other surface modifications, so that the polyaniline nano-microspheres prepared by the present invention can be used in electrochemical super The field of capacitors has a better application prospect. The preparation method of the invention is simple, the conditions are mild, there is no metal ion interference, the reproducibility is good, and the practicability is strong.

Description of drawings

Fig. 1 is the field emission scanning electron microscope micrograph of monodisperse polystyrene microsphere of the present invention;

Fig. 2 is the field emission scanning electron microscope micrograph of aminated polystyrene microsphere of the present invention;

Fig. 3 is the field emission scanning electron microscope micrograph of the polyaniline nano-microsphere 1 of embodiment 1;

Fig. 4 is the field emission scanning electron microscope micrograph of the polyaniline nano-microsphere 2 of embodiment 2;

Fig. 5 is the field emission scanning electron microscope micrograph of the polyaniline nano microsphere 3 of embodiment 3;

Fig. 6 is the field emission scanning electron microscope micrograph of the polyaniline nano microsphere 4 of embodiment 4;

Fig. 7 is the field emission scanning electron microscope micrograph of the polyaniline nano microsphere 5 of embodiment 5;

FIG. 8 is a field emission scanning electron micrograph of the polyaniline nanospheres 6 of Example 6. FIG.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the implementation of the present invention will be further described in detail below in conjunction with specific examples.

Example 1

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 40° C. for 2 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with Na ₂ S ₂ O ₄ at 70° C. for 5 h to obtain aminated polystyrene microspheres;

(4) After dissolving 0.2g aniline in chloroform to obtain aniline solution, then drop the acidic aqueous solution of 0.2g above-mentioned aminated polystyrene microspheres, 0.14g sodium dodecylsulfonate and 0.49g initiator ammonium persulfate Add it to the above aniline solution, the molar ratio of aniline to ammonium persulfate is 1:1, and the acidic aqueous solution is an aqueous hydrochloric acid solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at -5°C for 24 hours, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 1 with a core-shell structure.

Example 2

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 50° C. for 1 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with sodium borohydride at 80° C. for 2 h to obtain aminated polystyrene microspheres;

(4) After dissolving 0.4g of aniline in chloroform to obtain aniline solution, the acidic aqueous solution of 0.2g of the above-mentioned aminated polystyrene microspheres, 0.118g of sodium dodecylsulfonate and 0.98g of initiator ammonium persulfate was dropped Add it to the above aniline solution, the molar ratio of aniline to ammonium persulfate is 1:1, and the acidic aqueous solution is a sulfuric acid aqueous solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at 5° C. for 10 h, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 2 with a core-shell structure.

Example 3

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 45° C. for 1.5 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with sodium borohydride at 75° C. for 3 h to obtain aminated polystyrene microspheres;

(4) After dissolving 0.8g of aniline in chloroform to obtain aniline solution, the acidic aqueous solution of 0.2g of the above-mentioned aminated polystyrene microspheres, 0.25g of sodium dodecylsulfonate and 1.96g of initiator ammonium persulfate was dropped Add it to the above aniline solution, the molar ratio of aniline to ammonium persulfate is 1:1, and the acidic aqueous solution is an aqueous hydrochloric acid solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at 0° C. for 20 h, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 3 with a core-shell structure.

Example 4

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 50° C. for 1 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with sodium borohydride at 80° C. for 2 h to obtain aminated polystyrene microspheres;

(4) After 0.4g aniline is dissolved in chloroform to obtain aniline solution, then the acidic aqueous solution of 0.2g above-mentioned aminated polystyrene microspheres and 0.98g initiator ammonium persulfate is added dropwise in the above-mentioned aniline solution, aniline and persulfate The molar ratio of ammonium sulfate is 1:1, and the acidic aqueous solution is a sulfuric acid aqueous solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at 5° C. for 10 h, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 4 with a core-shell structure.

Example 5

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 50° C. for 1 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with sodium borohydride at 80° C. for 2 h to obtain aminated polystyrene microspheres;

(4) After dissolving 0.2g aniline in chloroform to obtain aniline solution, then drop the acidic aqueous solution of 0.2g above-mentioned aminated polystyrene microspheres, 0.08g sodium dodecylsulfonate and 0.245g initiator ammonium persulfate Add it to the above-mentioned aniline solution, the molar ratio of aniline to ammonium persulfate is 1:0.5, and the acidic aqueous solution is a sulfuric acid aqueous solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at 5° C. for 10 h, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 5 with a core-shell structure.

Example 6

(1) Add 95mL of ethanol, 5mL of deionized water, and 1.818g of polyvinylpyrrolidone into a four-neck flask. Under nitrogen protection, after magnetic stirring at 70°C for 20min, add 20g of styrene and 0.182g of azobisisobutyl Nitrile, magnetically stirred for 12 hours, then naturally cooled to obtain a white emulsion. The product was washed with absolute ethanol, centrifuged and vacuum-dried at room temperature for 10 hours to obtain polystyrene microsphere powder.

(2) ultrasonically disperse the above polystyrene microsphere powder into a mixed acid with a volume ratio of concentrated sulfuric acid and concentrated nitric acid of 3:2, react at 50° C. for 1 h, wash and dry to obtain nitrated polystyrene microspheres;

(3) Reducing the above-mentioned nitrated polystyrene microspheres with sodium borohydride at 80° C. for 2 h to obtain aminated polystyrene microspheres;

(4) After dissolving 0.2g aniline in chloroform to obtain aniline solution, then drop the acidic aqueous solution of 0.2g above-mentioned aminated polystyrene microspheres, 0.2g sodium dodecylsulfonate and 1.225g initiator ammonium persulfate Add it to the above-mentioned aniline solution, the molar ratio of aniline to ammonium persulfate is 1:5, and the acidic aqueous solution is an aqueous hydrochloric acid solution with a concentration of 0.5mol/L. After the system was stabilized, reacted at 5° C. for 10 h, added acetone, filtered, washed with ethanol, and dried to obtain the polyaniline nanospheres 6 with a core-shell structure.

The polystyrene microspheres obtained in step (1) of the above embodiments, the aminated polystyrene microspheres obtained in step (3), and the polyaniline nanospheres 1-6 of the core-shell structure are scanned by an electron microscope to obtain The micrographs of the field emission scanning electron microscope are shown in Figures 1-8. It can be seen from the drawings that the polyaniline nanospheres with core-shell structure obtained in the present invention not only have good appearance and uniform size, but also have good monodispersity and are not easy to agglomerate. At the same time, each polyaniline-wrapped microsphere of the polyaniline nano-microsphere prepared by the present invention contains a number of aminated polystyrene, which increases its surface area.

After secondary doping with hydrochloric acid, the polyaniline nanospheres 1-6 were tested for electrical conductivity and cyclic voltammetry, and the results showed that they had good electrical conductivity and good energy storage performance.

Adding the above-mentioned polyaniline nano-microspheres 1-6 into water shows that they have good dispersion and are not easy to agglomerate.

It should be noted that: the above-mentioned embodiments only list a few structures, and those of ordinary skill in the art can obtain corresponding structures by using the methods in the embodiments, only the data are modified, and they are not listed one by one.

The serial numbers of the above embodiments of the present invention are for description only, and do not represent the advantages and disadvantages of the embodiments.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (9)

1. a kind of preparation method of the polyaniline nano microballoon with nucleocapsid, step include：

(1) polystyrene microsphere of monodispersity is prepared；

(2) by the polystyrene microsphere ultrasonic disperse to nitrating agent in step (1), 1~2h is reacted at 40~50 DEG C, is washed It washs, be dried to obtain nitrification polystyrene microsphere；

(3) amination polystyrene microsphere will be obtained after the nitrification polystyrene microsphere reduction in step (2)；

(4) aniline is dissolved in after obtaining aniline solution in non-polar organic solvent, then amination described in step (3) will be contained The acidic aqueous solution of polystyrene microsphere and initiator is added drop-wise in above-mentioned aniline solution, after stable system, at -5~5 DEG C Reaction 10~purify afterwards for 24 hours obtains the polyaniline nano microballoon with nucleocapsid after drying；In the acidic aqueous solution Dodecyl sodium sulfate also containing Solute mass 10~20%.

2. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Polystyrene microsphere in step (1) is prepared by the method for emulsifier-free emulsion polymerization.

3. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Nitrating agent in step (2) is the concentrated sulfuric acid and concentrated nitric acid volume ratio is 3:2 mixed acid.

4. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Reduction in step (3) is to pass through Na₂S₂O₄Or sodium borohydride reductase 12~5h at 70~80 DEG C is obtained.

5. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Initiator is ammonium persulfate.

6. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Acidic aqueous solution in step (4) is the sulfuric acid or aqueous hydrochloric acid solution that concentration is 0.5mol/L.

7. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described Purifying in step (4) is filtered after acetone is added, and is obtained after then being washed with ethyl alcohol.

8. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described The mass ratio of amination polystyrene microsphere and aniline is 1 in step (4):(1~4).

9. the preparation method of the polyaniline nano microballoon with nucleocapsid according to claim 1, it is characterised in that：It is described The molar ratio of aniline and initiator is 1 in step (4):(0.5~5).