KR20010109812A - Method of making a soluable polyaniline salt in a diversified organic polar solution - Google Patents

Abstract

The present invention relates to a method for preparing a polymer polyaniline salt having solubility in various organic polar solvents. According to the method of the present invention, the polyaniline salt is prepared by doping aniline monomer in the presence of an oxidizing agent and then doping with a dopant. It is preferable to use a polar dialkyl sulfate as the dopant, and ammonium persulfate is preferable as the oxidant.

According to the present invention, excellent thermal and atmospheric stability in the air, easy to electrochemical and chemical synthesis, and excellent solubility in various organic solvents to bring advantages in the workability, antistatic, electromagnetic wave absorbers, electromagnetic wave shielding paints and coating materials, storage batteries Polymer electrolytes for capacitors, photochemical cells, electrochromic devices, corrosion protection, resistive heating, cable shielding, microwave absorbers, temperature, shock, chemical sensors, EL devices Soluble polyaniline salts, which are highly applicable to nanofibers, optical fibers and optical transducers, can be synthesized by chemical methods.

Description

Method of making a soluable polyaniline salt in a diversified organic polar solution

The present invention relates to a process for preparing polyaniline salts having solubility in various organic polar solvents.

With the advancement and precision of science and technology, the demand for new materials is becoming more diverse. In response to such demands, conductive polymers have recently attracted attention as new functional materials. Conductive polymers are materials that have both electrical, magnetic and optical properties of metals, and mechanical properties and processability of conventional polymers. They are light and flexible, and their electric conductivity and electronic state are freely controlled. In addition, since it can be applied in various forms to the special application surface that was not feasible in the past, many basic and application studies have been conducted to realize this.

Among these conductive polymers, in particular, polyaniline is easy to synthesize and make derivatives, and has been widely studied worldwide because of its advantages of high electrical conductivity, high thermal and atmospheric stability, and low price.

Polyaniline is a water-insoluble black polymer obtained by oxidative polymerization in an acid solution of aniline or aniline derivatives, called "aniline black" and the name emeraldine for the first time in Octamer partially oxidized by Green and Woodhead. It became.

In 1910-1912, polyaniline was reported to exist in four different oxidation states, each as an octopus, followed by a study on the electrochemical oxidation of aniline in the 1950s and 1960s. In particular, since Macdiarmid reported that, in 1985, the median oxidation state of polyaniline, emeraldine base, increased the conductivity by about 10 to ¹⁰ times due to the doping of a positive asset, it became a great interest as a conductive polymer and has been studied by many researchers around the world. Started.

Polyaniline is an aromatic compound in which the polymer itself is nonpolar, and it has been reported that up to about 10 years ago, it was insoluble in most organic solvents or water regardless of the synthesis method. However, solubility studies continue to report that emeraldine base is partially dissolved in 80% acetic acid, 88% formic acid, and DMSO. In 1988, M. Angelopoulos et al reported that polyaniline (emeraldine base) showed improved solubility in NMP ( N- methyl-2-pyrrolidinone), a relatively weak polar solvent, and processed it into various types of films, fibers, and elastomers. This became possible. In 1989, AG Macdiarmid et al reported that derivatives substituted with large substituents (-CH ₃ , -OCH _3, etc.) in the benzene ring weakened the chain-to-chain bonds, thereby increasing the solubility in general organic solvents significantly. However, the electrical conductivity was low due to the decrease in the conjugate length due to the distortion between the benzene rings under the influence of large substituents.

In 1990, Cao et al. Reported that the emeraldine base was dissolved in concentrated sulfuric acid and processed conductive fibers therefrom to report an electrical conductivity of about 200 S / cm, followed by 1992 methanesulfonic acid (HCSA) and dodecylbenzenesulphonic acid (HDBSA). Polyaniline doped with a functional acid such as) increases the solubility in weak or very nonpolar solvents such as m -cresol by the action of counterion and solvation, and increases the crystallinity and electron mobility of the polymer. It has been reported to exhibit high electrical conductivity of 400 S / cm. In addition, by branding it with commercially available polymers, the processability is significantly improved.

1994 A.G. MacDiarmid et al. Anticipate that the electrical conductivity of doped polyaniline is enhanced by the solvent used, and that the polymer chain conformation is determined by the change of solvent through systematic studies. As a result, the concept of secondary doping in which charge mobility is affected is described.

However, in recent years, as the regulation of VOCs and the green round have been raised around the world, there are many restrictions on the use of highly carcinogenic organic solvents. Therefore, the researchers are doing a lot of research to improve the processability of polyaniline for low-toxic polar solvents such as water and alcohol.

In general, polyaniline is an aromatic compound in which the polymer itself is a nonpolar compound, but a small amount of polyaniline is dissolved in the nonpolar solvent. However, polyaniline does not dissolve at all in a polar solvent such as alcohol. In order to develop polyaniline soluble in polar solvents such as alcohols, new dopants and polymer structures have to be devised based on the research results so far.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, to provide a method for preparing a conductive polyaniline salt having solubility in various organic polar solvents.

The inventors have studied extensively and intensively for the preparation of polyaniline salts soluble in organic polar solvents as described above. As a result, the polyaniline salts can be prepared by doping polyaniline bases using a functional dopant, dialkylsulfonate. It was found that the present invention was completed.

1 is a graph showing ultraviolet (UV) peak measurements up to the near infrared region by dissolving polyaniline doped with diethyl sulfate, a polyaniline salt prepared in the present invention, in various polar solvents,

2 is a graph showing the change in electrical conductivity with time at 160 degrees between the polyaniline salt [EB-DES / film] prepared in the present invention and a general polyaniline salt (EB-HCl / film).

The present invention provides a method for preparing a polymer polyaniline salt, which is soluble in an organic polar solvent. According to the present invention, a polyaniline base of formula (1) is doped with a diethylsulfate of formula (2) as a functional dopant at 95 ° C at room temperature. A method for preparing a conductive polymer polyaniline salt of formula (3) soluble in an organic polar solvent is provided.

(Formula 1)

The compound of Formula 1 is a general structural formula of polyaniline is composed of a repeated form of the reduced state and the oxidation state is called emeraldine (1-y = 0.5: intermediate oxidation type) base.

(Formula 2)

The compound represented by the formula (2) is diethyl sulfate in which n is 2.

(Formula 3)

The compound represented by Formula 3 is a polyaniline salt doped with diethyl sulfate.

More specifically, the present invention provides a method for preparing a conductive polymer polyaniline salt of formula (3) soluble in an organic polar solvent by doping a dopant represented by formula (2) to a polyaniline base of formula (1).

The polyaniline salt prepared by the method according to the present invention has an excellent solubility in alcohols and general organic solvents, which are environmentally friendly solvents, and thus have great processability. Soluble polyaniline salts of the present invention having advantages in electrical conductivity as well as processability include antistatic, electromagnetic wave absorbers, coatings and coating materials for electromagnetic wave shielding, transparent conductive electrodes, hole injection electrodes in light emitting diodes and hole transport layer applications, storage batteries and capacitors. Polymer electrolyte, photoelectrochemical cell, electrochromic display, corrosion protection, resistive heating, cable shielding, microwave absorber, temperature, shock, chemical This material is highly applicable to sensors, nano fiber processing and optical transducers.

Polyaniline salts have good thermal atmospheric stability and have electrical conductivity, but they do not dissolve well in general polar organic solvents due to strong attractive force between and between chains. Thus far, polyaniline bases are prepared by treating polyaniline salts to prepare n-methylpi. After dissolving and processing in Ralidone (NMP), conductivity was given. As such, when the polyaniline base is prepared and has conductivity, a good quality film can be obtained, but it has a disadvantage in that workability is cumbersome.

However, Cao et al. Recently reported that the emeraldine base is well dissolved in concentrated sulfuric acid and processed conductive fibers therefrom, reporting an electrical conductivity of about 200 S / cm, followed by 1992 methanesulfonic acid (HCSA) and dodecylbenzenesulphonic acid ( Polyaniline doped with a functional acid such as HDBSA) increases the solubility in weak or very nonpolar solvents such as m -cresol as a function of counterion and solvation, and increases the crystallinity and electron mobility of the polymer. It was reported that the electrical conductivity was ˜400 S / cm.

However, even in the case of polyaniline salts doped with functional acids such as conventional camphorsulphonic acid (HCSA) and dodecylbenzenesulphonic acid (HDBSA), the polymer itself is a non-polar aromatic compound, but is dissolved in a small amount in a nonpolar solvent, but is a polar solvent such as alcohol. Has the characteristic of not dissolving at all.

A study on the water solubility of polyaniline was done by Epstein et al. It has been reported that when polyaniline base and fuming sulfuric acid are treated at low temperature, a hydrophilic substituent, -SO ₃ H, is substituted with phenyl ring to obtain a sulfonated polymer which is dissolved in an aqueous solution according to a mechanism called self-doping. In 1995, SC Ng used phosphonic acid to solubilize polyaniline and exhibit an electrical conductivity of 10 ⁻⁴ S / cm. However, these results showed the possibility of dissolving in a polar solvent such as water by the introduction of a hydrophilic substituent on polyaniline, but did not attract much attention due to the difficulty of the substitution reaction and low electrical conductivity.

In order to solve the above problems, a polyaniline salt doped in various molar ratios to a polyaniline base using diethylsulfate, a polar functional group, is used as a dopant to prepare environmentally friendly solvents such as methyl alcohol, ethyl alcohol, 1-butanol, Alcohols such as isopropyl alcohol, isobutyl alcohol, t -butyl alcohol, benzyl alcohol, 2,2,2-trifluoroethanol, oleyl alcohol, ethylene glycol and the like and formic acid, 1-methyl-2-pyrrolidinone Polar solvents such as (NMP), dimethyl sulfoxide (DMSO), N, N' -dimethylformamide (DMF), etc., and weak polarities such as o -chlorophenol, m -cresol, tetrahydrofuran (THF), acetic acid, Soluble polyaniline salts excellent in solubility in various organic solvents such as trifluoroacetic acid and the like were synthesized.

The sulfate ions of the dialkyl sulfates used as functional dopants in the present invention serve as good leaving groups.

The dialkyl sulfate used as the functional dopant used in the present invention has a large size of the molecule, thus increasing the distance between the polymer chain and the chain, and the relative ion in the dialkyl sulfate is a polar solvent such as dimethyl sulfoxide (DMSO). Since it contains a polar functional group (sulfate) similar in structure and affinity between the polymer chain and the solvent can be seen to be dissolved in a polar solvent.

Hereinafter, according to the method of the present invention, a method for synthesizing a conductive polyaniline salt soluble in an organic polar solvent will be described in detail.

<Example 1>

Synthesis of polyaniline salts having solubility in various organic polar solvents of the present invention is as follows.

Aniline (C ₆ H ₅ NH ₂ , 99.5%, purchased by Aldrich Co.) was purified using a general vacuum distillation apparatus, and stored in a refrigerator in a brown bottle. Ammonium persulfate [(NH ₄ ) ₂ S ₂ O ₈ )] to be used as an oxidant was purchased (Aldrich Co.) and used as it is.

First, 500 ml 1 mol hydrochloric acid solution was prepared. 20 ml of aniline was dissolved in 300 ml of 1 mol hydrochloric acid solution and stored at room temperature. Separately, 11.5 g of [(NH ₄ ) ₂ S ₂ O ₈ ] was dissolved in 200 ml of 1 mol hydrochloric acid solution and stored at room temperature. The solution with oxidant was slowly added to the solution with aniline.

After 90 minutes, the precipitate was filtered using a Whatman filter paper (# 1) in a Buchner funnel connected to an aspirator, and the precipitate was washed with each used positive asset. The filtered piece (sample) was again made into a turbid solution in 10 ml of 1 mole hydrochloric acid, and then stirred in a 500 ml 1 mole hydrochloric acid solution and stirred with a magnetic paddle for 15 hours, followed by aspiration using Whatman filter paper (# 2). Filtration was carried out in a Buchner funnel connected to the radar. At this time, 2L of 1 mol hydrochloric acid was used to wash the filtrate until it was completely colorless.

This gave 50% protonated polyaniline. A 50% protonated polyaniline hydrochloride fragment was put back into 500 ml 0.1 normal ammonia solution and stirred for 15 hours with a magnetic paddle. At this time, the reaction solution was adjusted to pH 9 with 0.1 normal ammonia solution. The reaction solution was filtered after 15 hours and washed with 0.1 normal ammonia solution. The filtered pieces were put in a drying tube connected to a vacuum line and dried under vacuum (about 10 ⁻³ torr) for 48 hours to prepare a polyaniline base (emeraldine base) of Formula 1. 1 mole of polyaniline base prepared at 30 ° C. and 3 mole of diethylsulfate of Formula 2 are environmentally friendly protic solvents such as methyl alcohol, ethyl alcohol, 1-butanol, isopropyl alcohol, isobutyl alcohol, t Alcohols such as butyl alcohol, benzyl alcohol, 2,2,2-trifluoroethanol, lauryl alcohol, oleyl alcohol, ethylene glycol and the like; And organic solvents such as 1-methyl-2-pyrrolidone (NMP), acetic acid, dimethyl sulfoxide (DMSO), N, N' -dimethylformamide (DMF) and tetrahydrofuran (THF). After dissolving and knocking with ultrasonic waves to dissolve the efficiency of doping in an ultrasonic cleaner for 30 minutes, a polyaniline salt solution could be prepared. It showed an electrical conductivity of 20 ~ 10 ^-3 S / cm during film preparation from the prepared solution.

<Example 2>

Aniline (C ₆ H ₅ NH ₂ , 99.5%, purchased by Aldrich Co.) was purified using a general vacuum distillation apparatus, and stored in a refrigerator in a brown bottle. Ammonium persulfate [(NH ₄ ) ₂ S ₂ O ₈ )] to be used as an oxidant was purchased (Aldrich Co.) and used as it is.

First, 1 mole hydrochloric acid solution was prepared in 500 ml of a mixture of water and methanol (water: methanol = 50: 50). 20 ml of aniline was dissolved in 300 ml of 1 mol hydrochloric acid mixed solution and stored at room temperature. Separately, 11.5 g of [(NH ₄ ) ₂ S ₂ O ₈ ] was dissolved in 200 ml of 1 mol hydrochloric acid solution of water and methanol mixed solution (water: methanol = 50: 50) and stored at room temperature. The solution with oxidant was slowly added to the solution with aniline. Thereafter, a polyaniline salt was prepared in the same manner as in Example 1. It showed an electrical conductivity of 5 ~ 10 ^-5 S / cm at the time of film preparation from the prepared solution.

<Example 3>

At room temperature, 0.1 moles of sodium dodecylsulfate (SDS) and 0.1 moles of aniline were mixed in a reaction vessel, and 20 ml of 0.1 M HCl solution was slowly added thereto, and the mixture was stirred with a magnetic spoon for 60 minutes until the mixture became opaque.

Thereafter, the reaction solution was heated to 80 ° C. and the heating was stopped when the solution became clear. The reaction solution was allowed to cool until it reached 25 ° C. When the temperature of the solution reached room temperature, 0.05 mol of oxidizing agent [(NH ₄ ) ₂ S ₂ O ₈ ] was separately dissolved in 20 ml of 0.1 M HCl solution, and the solution containing the oxidizing agent was added to the reaction vessel containing aniline over 1 minute. Added. The reaction proceeds slowly, stirring with a magnetic spoon for 24 hours. The subsequent process was carried out in the same manner as the polymerization of aniline. 1 mole of polyaniline base prepared at 30 ° C. and 3 mole of diethylsulfate of Formula 2 are environmentally friendly protic solvents such as methyl alcohol, ethyl alcohol, 1-butanol, isopropyl alcohol, isobutyl alcohol, t − Alcohols such as butyl alcohol, benzyl alcohol, 2,2,2-trifluoroethanol, lauryl alcohol, oleyl alcohol, ethylene glycol and the like; And organic solvents such as 1-methyl-2-pyrrolidone (NMP), acetic acid, dimethyl sulfoxide (DMSO), N, N' -dimethylformamide (DMF) and tetrahydrofuran (THF). After dissolving and knocking with ultrasonic waves to dissolve the efficiency of doping in an ultrasonic cleaner for 30 minutes, a polyaniline salt solution could be prepared. It showed an electrical conductivity of 5-10 ^-4 S / cm when preparing the film from the prepared solution.

<Example 4>

2-Ethocyanine was purified after vacuum distillation and ammonium persulfate was purchased from Aldrich Co. and used as it was.

30.7 mL (0.22 mole) of 2-ethoxyaniline was dissolved in 300 mL 1M hydrochloric acid (HCl) and cooled to 0 ° C., and 11.5 g (0.05 mole) of ammonium persulfate [(NH ₄ ) ₂ S ₂ O ₈ ] was dissolved in 200ml 1M hydrochloric acid (HCl) and stored at 0 ° C. The solution containing the 2-ethoxyaniline (2-ethoxyani-line) was stirred with a magnetic straw and the solution containing the oxidant was added over 2 minutes and left for 120 minutes. The subsequent procedure was carried out in the same manner as the polymerization of aniline. A polyethoxyaniline base of formula 4 was prepared.

1 mole of polyethoxyaniline base prepared at 30 ° C. and 3 mole of diethylsulfate of formula 2 are environmentally friendly protic solvents such as methyl alcohol, ethyl alcohol, 1-butanol, isopropyl alcohol, and isobutyl alcohol. alcohols such as t -butyl alcohol, benzyl alcohol, 2,2,2-trifluoroethanol, lauryl alcohol, oleyl alcohol, ethylene glycol and the like; And organic solvents such as 1-methyl-2-pyrrolidone (NMP), acetic acid, dimethyl sulfoxide (DMSO), N, N' -dimethylformamide (DMF) and tetrahydrofuran (THF). After dissolving and hitting with ultrasonic waves to dissolve the efficiency of doping in an ultrasonic cleaner for 30 minutes, a polyethoxyaniline salt solution of Formula 4 could be prepared. The film showed an electrical conductivity of 10 ⁻² −10 ⁻⁶ S / cm when the film was prepared.

(Formula 4)

(Formula 5)

Example 5

The conductive polyaniline salts prepared above are prepared by using functional polymers [polymethyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl alcohol ( PVA), polyvinylacetate, polyacrylonitrile (PAN), polyvinyl butyral, acrylonitrile-butadiene-styrene (ABS), nylon (Nylon 6, 12, 6.6), polyurethane, epoxy, acrylic resin, nitrocellulose (nitrocellulose), methyl cellulose (methylcellulose), etc.] and blend in methyl alcohol, ethyl alcohol, 1-butanol, isopropyl alcohol, isobutyl alcohol, t - butyl alcohol, benzyl alcohol, 2, 2 Alcohols such as, 2-trifluoroethanol, oleyl alcohol, ethylene glycol and the like and formic acid, 1-methyl-2-pyrrolidinone (NMP), dimethyl sulfoxide (DMSO), N, N' -dimethylform Polar solvents such as amide (DMF) and the like E.g. o - chlorophenol, m -.-Cresol, tetrahydrofuran (THF), 5-90, respectively in a non-polar solvent such as a variety of organic solvents, and for example, chloroform, dichloromethane, benzene, such as acetic acid, trifluoroacetic acid wt% / wt. melt to prepare a conductive polyaniline salt blend.

The present invention not only enables the improvement of workability according to workability by preparing a soluble and conductive polyaniline salt having excellent solubility in general organic solvents, as well as alcohols, which are environmentally friendly solvents, and can be competitively priced compared to conventional metals. Therefore, it is expected to have a lot of influence on related industries. Soluble, conductive polypyrrole is an antistatic, electromagnetic wave absorber, electromagnetic wave shielding coating material and conductive paint development, storage battery, electrochemical battery, electrochromic display, corrosion preventing paint, transparent conductive electrode It can be applied to polymer electrolyte, metallization, resistive heating, cable shielding, microwave absorbor, temperature, shock, chemical sensor, nano fiber, optical transducer for capacitor.

Claims (8)

A method for preparing a polymer polyaniline salt having solubility in various organic polar solvents, wherein the polyaniline salt of Formula 3 is soluble in alcohol and organic solvent by doping the polyaniline base of Formula 1 with diethylsulfate, which is a functional dopant of Formula 2. Method for producing a conductive polymer polyaniline salt, characterized in that. The method of claim 1, R in Formula 4 is hydrogen, alkyl of 1 to 10 carbons, alkyl, isoalkyl, alkoxy, alkoxyalkyl, alkoxyalkyl, alkylsulfonyl nyl), alkoxycarbonyl, alkylsilane, arylsulfonyl lfonyl), a method for producing a conductive polyaniline substituent salt, characterized in that the alkenyl (alkenyl). The method according to claim 1 or 2, The dopant is a method for producing a conductive polyaniline salt, characterized in that n in the formula 2 dialkyl sulfate of 1 to 10. The method according to claim 1 or 2, A method for preparing a conductive polyaniline salt soluble in alcohols and organic solvents, characterized in that the dopant molar ratio of formula (2) according to the polyaniline base of formula (1) is doped at 0.5 molar ratio to 10 molar ratio. The method according to any one of claims 1 to 2, Method for producing a conductive polymer polyaniline salt, characterized in that the dopant of the formula (2) is added to the sonicator for 30 minutes or more after doping the polyaniline base of the formula (1). The method according to any one of claims 1 to 3, In the reaction of preparing the polyaniline base of Formula 1, the solvent is prepared in water, an organic solvent [alcohol (butanol, methanol, chloroform, dichloromethane, acetonitrile, formic acid, acetic acid, etc.)] or a mixed solvent of water and an organic solvent. Method for producing a conductive polymer polyaniline salt, characterized in that the doped dopant of formula (2). The method according to any one of claims 1 to 3, The prepared conductive polyaniline salts are made of functional polymers [polymethyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl alcohol (PVA) , Polyvinylacetate, polyacrylonitrile (PAN), polyvinyl butyral, acrylonitrile-butadiene-styrene (ABS), nylon (Nylon 6, 8, 12, 6.6), polyurethane, epoxy, Acrylic resin, nitrocellulose, methylcellulose, etc.] and a method for producing a conductive polyaniline salt blend by dissolving in alcohols and various organic solvents. The method of claim 7, wherein A method for producing a conductive polyaniline salt blend, characterized in that the addition ratio of the functional polymer is 5 to 90%, respectively.