JPH10251510A - Electroconductive polyaniline complex and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject complex useful for a positive electrode material of a secondary battery, etc., capable of extremely improving electrical conductivity of a polyaniline, excellent in practical moldability, stability, etc., by dispersing very fine inorganic particles into a polyaniline. SOLUTION: This complex is obtained by dispersing (B) very fine inorganic particles into (A) a polyaniline or its derivative. The component B is porous particles, has <=100nm particle diameter and an oxide, to be concrete, TiO2 is used as the component B. The complex is obtained by compounding an aqueous or organic solvent solution of the component A with the component B in the blending amount of the component B of preferably about 10-80wt.% based on the total of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polyaniline composite and a method for producing the same.

[0002]

2. Description of the Related Art Aromatic conductive polymers such as polyaniline, polyphenylene, polythiophene, and polypyrrole have excellent stability in air and are easy to synthesize, so they are studied for application. The number is growing. Among them, polyaniline has excellent stability among conductive polymers and is an inexpensive material, so it is the first conductive polymer material to be practically used as a positive electrode material for secondary batteries. Polyaniline is characterized by its unique electrochemical properties
Many application fields are being studied, including positive electrode materials for secondary batteries, electrochromic materials, various sensor materials, antistatic paints, electromagnetic shielding materials, optical recording elements, solid electrolytic capacitor materials, plastic metal plating bases,
Artificial muscle material, various micro sensors, humidity sensor,
The application of anticorrosive paints, dispersants for electrorheological fluids, and the like is under study, and if practically used, it is a functional material that is expected to have many effects in the fields of electricity, electronics, and machinery.

[0003] Conventionally, with respect to polyaniline having such characteristics, studies for improving its conductivity have been conducted.
This is mainly done in connection with the dopant. That is, attempts have been made to improve the solubility and conductivity by synthesizing polyaniline by changing various dopants incorporated into polyaniline. As a physical conductivity improving means, the conductivity in the stretching direction is improved by controlling the orientation by stretching. However, in the studies so far, neither the method based on the addition of the dopant nor the method based on the physical orientation control can significantly improve the conductivity. In any of the conventional methods, a means of heating is indispensable, but it is generally known that heat treatment causes a decrease in conductivity.

[0004] The invention of this application has been made in view of the above situation, and exceeds the disadvantages and limitations of the conventional method, and usually has an electric conductivity in the range of 2 to 5 S / cm. Greatly improve the conductivity of polyaniline,
Moreover, it is an object of the present invention to provide a conductive polyaniline which is practically excellent in moldability, stability and the like.

[0005]

Means for Solving the Problems The present invention provides a conductive polyaniline composite characterized in that fine inorganic fine particles are dispersed in polyaniline or a derivative thereof to solve the above problems. . Further, the present invention includes, as an embodiment thereof, a composite in which the fine inorganic fine particles are porous particles, and the fine inorganic fine particles having a particle diameter of 100%.
Also provided are a composite having a diameter of not more than nm, a composite in which the fine inorganic fine particles are an oxide, a composite in which polyaniline or its derivative is obtained by oxidative polymerization of aniline or its derivative monomer in an aqueous solution, and the like.

The present invention still further provides a method for producing the above-mentioned composite, comprising mixing fine inorganic fine particles in an aqueous or organic solvent solution of polyaniline or a derivative thereof and subjecting the mixture to heat treatment. The present invention also provides a method for producing a composite, a method for producing a molded article having a predetermined shape by heat treatment, and the like.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application has the above-mentioned features. However, in the present invention, the conductivity of polyaniline is usually in the range of about 2 to 5 S / cm at most. However, it has been found that the conductivity generally decreases when heat treatment is performed, but the conductivity is greatly improved when heat treatment is performed by mixing with inorganic particles having a small particle size, particularly, porous particles having a large surface area. It was completed based on the knowledge obtained. Such improvement in conductivity is a unique phenomenon that has not been observed so far, and has been found to be effective as a means for dramatically improving the conductivity of polyaniline.

The fine inorganic fine particles dispersed in polyaniline or a derivative thereof have a small particle size, preferably 100 nm or less, more preferably about 10 nm or less. Those fine particles having a large surface area, that is, porous ones are considered to be preferable. The type may be an oxide, a carbide, a metal, an alloy, an organic metal, or various kinds of a composite thereof, and may be titanium, zirconium, hafnium, vanadium, niobium, tantalum, tin, indium, aluminum, iron Examples thereof include compounds of various elements such as silicon and silicon, and carbon.

The derivatives of polyaniline include those having various substituents in the molecule of monomer aniline. Alternatively, it may be modified after the polymerization reaction. Polyaniline or a derivative thereof is mixed with the above-mentioned inorganic fine particles as an aqueous solution or a solution of various organic solvents, and subjected to heat treatment. The blending of the inorganic fine particles in this case varies depending on the type, particle size, etc., but generally, 10 to 80% by weight based on the total amount of the polyaniline or its derivative can be used as a standard. . When the solvent for mixing is water, the inorganic fine particles may be mixed following the oxidative polymerization of the monomer in the aqueous solution. When an organic solvent is used, various solvents such as hydrocarbons, halogenated hydrocarbons, alcohols, ethers, esters, amides, and sulfoxides may be used alone or as a mixture.

The heat treatment can be performed at a temperature of about 30 to 120 ° C. for about 0.5 to 5 hours. Of course, these are not limiting. This heat treatment can be performed at the same time as the formation of molded articles of various shapes, for example, together with the casting of a film. Hereinafter, examples will be shown, and embodiments of the present invention will be described in more detail.

[0011]

EXAMPLE First, a mixed solution of aniline or an aniline derivative, an anionic surfactant, and ammonium persulfate is prepared to prepare a uniform aqueous solution of polyaniline. That is, as a specific example, dodecylbenzenesulfonic acid (DBS) is added to 100 ml of a 0.2 mol aqueous solution of aniline hydrochloride.
A) 0.2 mol was added and dissolved by heating, and the solution was further added with 0.25 mol of ammonium persulfate while stirring at a low temperature of 0 ° C. or lower to carry out a reaction for 4 hours. As the reaction progressed from an initially heterogeneous system to a homogeneous one, a green aqueous solution unique to polyaniline was obtained. When acetone or methanol is added to the resulting polyaniline polymerization solution, a precipitate of polyaniline is obtained.
The obtained polyaniline is further solubilized in water by adding 0.2 mol of dodecylbenzenesulfonic acid (DBSA) to give an aqueous solution of polyaniline.

Next, ultrafine titanium dioxide having a particle size of 7 nm was mixed with an aqueous solution of polyaniline to form a uniform colloid solution, and cast as a film. This was heated at 85 ° C., and the conductivity was measured. FIG. 1 illustrates this process. Table 1 shows the measurement results of the conductivity.

Table 1 also shows the case where silica gel and vanadium pentoxide were added instead of titanium dioxide.
It was shown to. For comparison, Table 1 also shows the conductivity when inorganic fine particles were added, when dried at room temperature, and the like.

[0014]

[Table 1]

[0015]

As described above in detail, according to the present invention, the conductivity of polyaniline or a derivative thereof is greatly improved. For example, in practice, when a water-soluble polyaniline is cast as it is to form a heat-treated polyaniline film, the resistance value is large and 10 ⁵
Although it becomes −10 ⁶ ohms, it is mixed with inorganic fine particles to form a dispersion, cast, and heat-treated. The resistance of polyaniline is reduced by two to five orders of magnitude, and the conductivity is improved. By this technique, an effective electrical conductivity can be obtained with a small amount of polyaniline. This technique also provides a few means for improving the conductivity of polyaniline. This opens up the possibility of application of polyaniline, in which only the heat-treated portion has improved conductivity, and the other untreated portions remain low in conductivity. This thermal recording element utilizes this difference in conductivity. It is considered to be used as a material, and furthermore, brings a possibility that it can be applied to various applications in combination with other electronic materials.

The technique of the present invention has a possibility of being used as a means for improving the conductivity of not only polyaniline but also many conductive polymers and conductive substances.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a process according to an embodiment.

Claims (7)

[Claims] 1. A conductive polyaniline composite, wherein fine inorganic fine particles are dispersed in polyaniline or a derivative thereof. 2. The composite according to claim 1, wherein the fine inorganic fine particles are porous particles. 3. The composite according to claim 1, wherein the fine inorganic fine particles have a particle size of 100 nm or less. 4. The fine inorganic fine particles are oxides.
Or the complex of any one of (3) to (3). 5. The composite according to claim 1, wherein the polyaniline or a derivative thereof is obtained by oxidative polymerization of an aniline or a derivative monomer in an aqueous solution. 6. The method for producing a composite according to claim 1, wherein fine inorganic fine particles are mixed with an aqueous or organic solvent solution of polyaniline or a derivative thereof and heat-treated. Method for producing conductive polyaniline complex. 7. The method according to claim 6, wherein a molded article having a predetermined shape is produced by heat treatment.