CN100402583C - Synthetic method of polyaniline nanoparticles - Google Patents

Abstract

The invention discloses a synthesis method of polyaniline nanoparticles, relating to a synthesis method of polyaniline nanoparticles. After mixing the protonic acid dopant solution with a concentration of 0.1-4mol dm ^-3 , the aniline monomer solution with a concentration of 0.1-2mol dm ^- 3, and the rare earth chloride dopant solution with a concentration of 0.1-2mol dm ^-3 , pour it into In the reactor, add an external magnetic field on both sides of the reactor, control the magnetic field strength at 200-2000mT, and then add an oxidized initiator solution with a concentration of 0.1-1.0mol dm ^-3 into the reactor; the reaction temperature is normal temperature To 70°C, the reaction time is 1 to 8 hours. The invention has low synthesis cost and easy process control. The synthesized spherical polyaniline nanoparticles have a particle diameter of 30-100nm. The polyaniline nano particles produced by the invention have broad application prospects in optoelectronic devices, information, sensors, molecular wires and molecular devices, as well as electromagnetic shielding and stealth technologies.

Description

Synthetic method of polyaniline nanoparticles

technical field

The invention relates to a synthesis method of polyaniline nanoparticles.

technical background

Polyaniline is an important conductive polymer material, which has the advantages of high electrical conductivity, good redox reversibility, and environmental stability. Mirmohseni A, Solhjo R. Preparation and characterization of aqueous polyaniline battery using a modified polyaniline electrode. Euro. Polym. J. 2003; 39(2): 219-223. Moraes SR, Huerta-Vilca D, Motheo AJ. Characteristics of polyaniline synthesized in phosphate buffer solution. Euro. Polym. J. 2004; 40(9): 2033-2041. The macromolecular complexes formed by the reaction of polyaniline and rare earth ions have special chemical and physical properties. In the past two decades, nanoparticles have attracted widespread attention due to their special physical and chemical properties, and people's interest in conductive polymer nanoparticles mainly stems from their application in catalysis, molecular electronics, energy conversion devices and medicine. Controlled release medium. Generally, the techniques for preparing polymer nanoparticles include "template synthesis method", "microemulsion method", "freeze-drying method", "spray coating method" and "surface spreading film repair method". The template method is usually divided into hard template method and soft template method. The dura sheets used such as porous alumina H.J.Qiu, J.Zhai, S.H.Li, M.X.Wan, Oriented growth of self-assembled polyanilinenanowire arrays using a novel method, Adv.Funct.Mater., 2003, 13, 925-928, Soft template method such as surfactant J.C.Michaelson and A.J.McEvoy, Chem.Commun., 1994, 1, 79-80. However, these methods often have the disadvantages of high cost, difficulty in template removal, and difficulty in mass production, so it is necessary to further improve their synthesis methods.

Contents of the invention

The purpose of the invention is to provide a synthetic method for spherical polyaniline nanoparticles.

After mixing the protonic acid dopant solution with a concentration of 0.1-4mol dm ^-3 , the aniline monomer solution with a concentration of 0.1-2mol dm ^- 3, and the rare earth chloride dopant solution with a concentration of 0.1-2mol dm ^-3 , pour it into In the reactor, add an external magnetic field on both sides of the reactor, the magnetic field strength is 200-2000mT, and then add an oxidized initiator solution with a concentration of 0.1-1.0mol dm ^-3 into the reactor; the reaction temperature is From normal temperature to 70°C, the reaction time is 1-8 hours; the protonic acid dopant solution is hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, perchloric acid or oxalic acid.

The invention uses protonic acid as a dopant to carry out oxidative polymerization reaction, and can be used to regulate the size of nanoparticles by controlling the reaction temperature, the concentration of protonic acid, the concentration of rare earth salt, the concentration of monomer, the concentration of initiator and the strength of magnetic field. The synthesis cost is low, and the process is easy to control. The synthesized spherical polyaniline nanoparticles have a particle diameter of 30-100nm. The polyaniline nano particles produced by the invention have broad application prospects in optoelectronic devices, information, sensors, molecular wires and molecular devices, as well as electromagnetic shielding and stealth technologies.

The weight ratio of the protonic acid dopant solution to the aniline monomer solution, the rare earth chloride dopant solution and the oxidized initiator solution is 3-7:9-90:30-40:20-200.

The oxidizing initiator described in the present invention is persulfate or ferric chloride.

The protic acid dopant is an inorganic acid.

The inorganic acid can be hydrochloric acid or sulfuric acid or nitric acid or phosphoric acid or perchloric acid.

The protonic acid dopant is an organic acid.

The organic acid is oxalic acid.

The rare earth chloride dopant may be SmCl ₃ or GdCl ₃ or LaCl ₃ or NdCl ₃ or ErCl ₃ .

Description of drawings

Fig. 1 is a scanning electron micrograph of a kind of polyaniline nano-particle obtained in the present invention.

Fig. 2 is a transmission electron micrograph of polyaniline nanoparticles obtained in the present invention.

Detailed ways

1. Preparation of reaction solution: concentration of protonic acid dopant (hydrochloric acid or sulfuric acid or nitric acid or phosphoric acid or perchloric acid or oxalic acid solution) is 0.1～2mol dm ^-3 ; concentration of aniline monomer solution is 0.1～1.0mol dm ^-3 ; The concentration of the rare earth chloride dopant solution (SmCl ₃ or GdCl ₃ or LaCl ₃ or NdCl ₃ or ErCl ₃ ) is 0.1-2mol dm ^-3 .

2. Preparation of oxidative initiator (ammonium persulfate or ferric chloride) solution: the concentration is 0.1-1.0 mol dm ^-3 .

3. Mix the prepared 3-7g proton dopant hydrochloric acid solution, 9-90g aniline monomer solution, and 30-40g rare earth dopant samarium chloride (SmCl ₃ ) solution evenly, and set aside.

4. Pour the above mixed solution into a closed reactor, and heat the reactor with a water bath to control the temperature below 70°C. Add a magnetic field with a magnetic field strength of 200-2000mT on both sides of the reactor, and gradually add 20-200g of the prepared oxidative initiator ammonium persulfate to the reactor within 10 minutes, and control the entire reaction time to 1-8 hours.

Above-mentioned hydrochloric acid solution can be replaced with sulfuric acid or nitric acid or phosphoric acid or perchloric acid or oxalic acid solution.

SmCl ₃ solution can be replaced by GdCl ₃ or LaCl ₃ or NdCl ₃ or ErCl ₃ solution.

Ammonium persulfate solution can be replaced by ferric chloride solution.

5. Analysis:

After the reaction was completed, a dark green suspension was obtained, which was filtered and washed with 1.0 mol dm ^-3 dilute hydrochloric acid until the filtrate was colorless. After drying, observe the morphology of the particles with a transmission electron microscope (TEM) or a scanning electron microscope (SEM). The product is mainly polyaniline nanoparticles with a diameter of 30-100 nm, as shown in Figures 1 and 2. Infrared spectrum and ultraviolet spectrum analysis showed that the product was doped polyaniline containing rare earth. The conductivity of the measured sample is roughly in the range of 0.1-10S cm ^-1 .

6. Application examples:

Compared with conventionally synthesized polyaniline, which is insoluble and infusible, which makes its processing difficult, the nanonization of polyaniline particles greatly broadens its application fields. An example is as follows:

1) Since the particle size of polyaniline nanoparticles is smaller than the wavelength of visible light, the amount of polyaniline aniline nanoparticles required to maintain the same conductivity of the conductive film made by blending polyaniline nanoparticles with ordinary plastics is much lower than that of conventional plastics. The amount of polyaniline used makes the visible light transmittance of the conductive film reach 95%, which cannot be achieved by conventionally synthesized polyaniline. At the same time, the use of polyaniline nanoparticles can also improve the mechanical properties of the conductive film.

2) Compared with conventionally synthesized polyaniline, the conductive film made of polyaniline nanoparticles blended with ordinary plastics has good conductivity, which makes it widely used in antistatic coatings and antistatic films. prospect.

3) In the field of metal anti-corrosion coatings, polyaniline nanoparticles also show unique properties superior to traditional polyaniline. The anti-corrosion coating composed of polyaniline nanoparticles with a particle size of 70-100nm can improve the anti-corrosion performance of metals by more than 70%.

In addition, the gas barrier performance of the self-supporting film made of polyaniline nanoparticles is also greatly improved, and its oxygen permeability coefficient is reduced by 400% compared with traditional polyaniline. It is expected to have a broad application prospect in plastic packaging film and plastic wrap.

Claims (4)

1. The method for synthesizing polyaniline nanoparticles, characterized in that the proton acid dopant solution with a concentration of 0.1 to 4mol dm ^-3 and the aniline monomer solution with a concentration of 0.1 to 2mol dm ^-3 and the rare earth with a concentration of 0.1 to 2mol dm ^-3 After the chloride dopant solution is mixed evenly, pour it into the reactor, apply an external magnetic field on both sides of the reactor, the magnetic field strength is 200-2000mT, and then add ^the Oxidative initiator solution; the reaction temperature is from normal temperature to 70°C, and the reaction time is 1-8 hours; the protonic acid dopant solution is hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, perchloric acid or oxalic acid. 2. according to the described synthetic method of claim 1, it is characterized in that the weight ratio of protonic acid dopant solution and aniline monomer solution, rare earth chloride dopant solution, oxidized initiator solution is 3～7: 9～90 : 30~40: 20~200. 3. according to the described synthetic method of claim 1 or 2, it is characterized in that described oxidation initiator is persulfate or iron trichloride. 4. The synthesis method according to claim 1 or 2, characterized in that the rare earth chloride dopant is SmCl ₃ or GdCl ₃ or LaCl ₃ or NdCl ₃ or ErCl ₃ .

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