RU2318020C1 - Method for production of aqueous dispersion of conductive polyaniline and polysulpho acid interpolymer complex - Google Patents

Abstract

FIELD: biotechnology, microelectronic.

SUBSTANCE: claimed method includes blending of aniline and polysulpho acid in aerobic conditions. As reaction catalyst laccase from basidial fungi immobilized on water insoluble carrier is used. Said invention is useful in production of light-emitting diodes, antistatic and anticorrosive coatings.

EFFECT: economic and environmentally friendly method.

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Description

The invention relates to biotechnology and has a wide scope. Polyaniline is one of the most important electrically conductive polymers because of its high chemical stability, relatively high electrical conductivity, ease of preparation, and the ability to change its physicochemical properties with temperature, pH of the solution, and electric potential. Electrically conductive polyaniline can be used in electronic and light emitting devices, protection against electromagnetic radiation, protection against corrosion, light current sources, antistatic protection and other fields (Jayashree Anand, Srinivassan. Palaniappan, DNSathyanarayana. Conducting polianiline blends and composites. // Prog. Polym. Sci. 1998, Vol.23, P.993-1018; WO 2004/030029, code A3, published April 8, 2004, Krebs, Frederik; Jorgensen, Mikkel; Almdal, Kristoffer; Smart, Peter, J. Conducting polymer divices for inter-converting light and electricity.

Typically, electrically conductive polyaniline is chemically synthesized in a strongly acidic environment by oxidative polymerization of a monomer (Handbook of conducting polymers. // Eds. T. A. Scotheim, R. L. Elsenbaumer, J. R. Reynolds. N. Y.:, M. Dekker. 1998, P. 94). Moreover, the properties of such a polymer depend on the ordering of its structure. As a rule, in the vast majority of cases, ammonium persulfate is used as an oxidizing agent (initiator) in an amount commensurate with the monomer concentration, but sometimes peroxides, ferric chloride, and dichromates are used as an oxidizing agent. The reduction products of these compounds pollute polyaniline and must be processed, which creates additional costs in the process of polyaniline synthesis. In addition, the synthesis in a strongly acidic environment requires the availability of corrosion resistant equipment.

The use of enzymes in the synthesis of polyaniline is of great interest, because allows the process to be carried out in ecologically clean and mild conditions with a high degree of control of the rate of polymerization initiation and to obtain a polymer in high yield.

Typically, electrically conductive polyaniline is water insoluble, which makes it difficult to use. One of the approaches allowing to obtain pseudo-water-soluble derivatives of polyaniline is a method based on the introduction of a water-soluble negatively charged polyelectrolyte into the solution during the synthesis of polyaniline. As a rule, these polymers contain sulfo groups, which serve as a “doping” agent, and on these polyelectrolytes, as on a matrix, nanoparticles of electrically conductive polyaniline are synthesized from the monomer. The physicochemical properties of the resulting aqueous dispersion of nanoparticles largely depend both on the chemical structure of the polymer dopant on which the polyaniline is synthesized and on the conditions for the polymerization of the monomer.

Matrix synthesis of electrically conductive polyaniline was carried out in one stage using both polymerization chemical initiators and biocatalysts (V.A. Ivanov, O.L. Gribkova, K.V. Cheberyako, A.A. Nekrasov, V.A. Tverskoy, A .V. Vannikov. Matrix synthesis of polyaniline in the presence of poly (2-acrylamido-2methyl-1-propanesulfonic acid) // Electrochemistry. 2004, v.40, No. 3, pp. 339-345; WO 2005/121217 code A1, published December 22, 2005 Hsu, Che-Hsiung, Uckert, Frank. P. Water dispersible polyanilines made with polymeric acid colloids for electronic application .; M. Thiyagurajan, LASamuelson, J. Kumar, ALCholli. Helical conformational specifity of enzymatically synthesized water- solubl e conducting polyaniline nanocomposites. // J. Am. Chem. Soc. 2003, Vol. 125, P.11502-11503; Zhe Jiu, Yongxuan Su, Yixiang Duan. A novel method for polyaniline synthesis with the immobilized horseradish peroxidase enzyme. / / Synth. Met. 2001, Vol.122, P.237-242; AVKaramyshev, SVShleev, OVKoroleva, AIYaropolov, I.Yu. Sakharov. // Laccase-catalyzed synthesis of conducting polyaniline // Enzyme and Microbial Technology, 2003, v. 33, p.556-564; US Patent, 20040023346, code A1, published February 5, 2004, Samuelson Lynne.A. Bruno Ferdinando, Tripathy Sukant. K., Tripathy Susan, Nagarajan Ramaswamy, Kumar Jayant, Liu Wei. Enzymatic polymerization.

The synthesis was carried out by sequentially mixing aqueous solutions of polysulfonic acid and aniline.

In chemical synthesis, the oxidative polymerization reaction was initiated, as a rule, by adding an aqueous solution of ammonium persulfate to the resulting mixture. The polymerization reaction was carried out with constant stirring. The reaction time and the ratio of aniline to ammonium persulfate were different in different works.

In the enzymatic matrix synthesis of polyaniline, an aqueous biocatalyst solution was added to the resulting mixture of aniline and polysulfonic acid. As the last used peroxidase from horseradish roots or laccase. The aniline polymerization reaction in the presence of peroxidase was carried out with constant stirring.

All of the above methods for producing an aqueous dispersion of polyaniline nanoparticles have disadvantages. The chemical method of initiating the polymerization of aniline on the matrix proceeds in an acidic environment and in the presence of significant amounts of a chemical initiator of the reaction, which requires the use of acid-resistant materials in the manufacture of equipment. Disposal of the resulting products of the reduction of the oxidizing agent (initiator) of the polymerization reaction requires significant costs. In addition, in the case of using ammonium persulfate as an initiator of oxidative polymerization of aniline, the sulfate anion formed during reduction competes with doping groups of the polymer matrix, which reduces the degree of ordering of the formed polyaniline particles.

Enzymatic matrix synthesis of polyaniline using peroxidases and laccases also has several disadvantages. Firstly, most peroxidases from various sources (except for peroxidase from palm leaves and soybeans (R. Cruz-Silva, J. Romero-Garcia, JL, Angulo-Sanchez, A. Ledezma-Perez, E. Arias-Marin, I. Moggio, E. Flores-Loyola. Template-free enzymatic synthesis of electrically conducting polyaniline using soybean peroxidase. // European Polymer J., 2005, V.41, P.1129-1135; AVCaramyshev, EGEvtushenko, VFIvanov , A.Ros Barswio, MGRoig, VLShnyrov, R. van Huystee, INKurochkin, A.Kh. Vorobiev, I.Yu. Sakharov. // Synthesis of Conducting Polyelectrolyte Complexes of Polyaniline anf Poly (2-acrilamido-1- mtthyl-1-propanesulfonic acid) Catalyzed by pH-Stable Palm Tree Peroxidase // Biomacromolecules, 2005, V.6, P.1360-1366) are acid labile and can be used in the synthesis at a solution pH above 4. oryh, the reaction mixture should be added in portions of the second substrate of the peroxidase - hydrogen peroxide so that its concentration in the conditions of synthesis was not higher 1mM At higher concentrations of hydrogen peroxide, peroxidase is inactivated with hydrogen peroxide to form an inactive compound.. Both in chemical synthesis and in the biocatalytic synthesis of electrically conductive polyaniline using peroxidase or laccase, the final product — the interpolymer complex of polyaniline and polysulfonic acid — is contaminated either with the products of chemical oxidant reduction or with enzymes that are in a homogeneous state in the reaction mixture. These contaminants alter the physicochemical properties of the resulting product. As a prototype, a method of enzymatic matrix synthesis of polyaniline was selected (AVKaramyshev, SVShleev, OVKoroleva, AIYaropolov, I.Yu. Sakharov. // Laccase-catalyzed synthesis of conducting polyaniline // Enzyme and Microbial Technology, 2003, v. 33, p.556-564), including the following sequence of operations:

- preparation of a mixture of aniline and matrix in 0.1 M citrate-phosphate buffer solution with a pH in the range of 3.5 ÷ 4.5,

- the introduction of the reaction mixture of laccase from the fungus Trametes hirsute.

The reaction was carried out within 24-72 hours. The solution was then dialyzed for 24 hours to remove the monomer.

Polysulfostyrene with a molecular weight of 70 kDa was used as a matrix for the synthesis of polyaniline.

The objective of the invention is to develop a simple, environmentally friendly matrix method for producing an aqueous dispersion of nanoparticles of electrically conductive polyaniline, not contaminated with the components of the reaction mixture (enzyme). The problem is solved by the proposed method, providing for the oxidative polymerization of aniline using an immobilized redox laccase enzyme (n-diphenol: oxygen oxidoreductase, EC 1.10.3.2) under aerobic conditions. This enzyme catalyzes the free radical oxidation of a wide range of organic compounds, including aromatic organic compounds with a lone pair of electrons, molecular oxygen and its simultaneous reduction directly to water. Sources of laccase were the culture fluid of the basidiomycete fungi Trametes hirsuta, Trametes pubescens, Trametes ochracea, Cerrena maxima, Coriolopsis fulvocinerea, Trametes versicolor.

The method includes the following stages: 1) synthesis of an aqueous dispersion of electrically conductive polyaniline particles in the process of aniline oxidative polymerization under aerobic conditions in the presence of polysulfonic acid dissolved in the reaction mixture at pH 2.5–5.5, temperature 4–35 ° C, catalyzed by immobilized laccase from basidiomycetes (Scheme 1 ); 2) removal of immobilized laccase from the reaction medium

Scheme 1. Enzymatic synthesis of an interpolymer complex of polyaniline and polysulfonic acid with immobilized laccase.

The enzymatic method for producing an aqueous dispersion of an interpolymer complex of electrically conductive polyaniline and polysulfonic acid, which is both a matrix in the synthesis and dopant using immobilized laccases from various sources, is environmentally friendly and allows you to get the final product (interpolymer complex of electrically conductive polyaniline and polysulfonic acid) not contaminated with the enzyme by immobilized enzyme from the reaction medium. Additionally, the immobilization of laccase allows you to use the enzyme repeatedly, which reduces the cost of synthesis.

The invention is illustrated by the following examples.

Example No. 1. 0.1 M citrate buffer solution pH 3.5, containing aniline at a concentration of 25 mM and poly (2-acrylamido-2metal-1-propanesulfonic acid) with a molecular weight of 1000 kDa, at a concentration of 25 mM, calculated per polymer unit, (ratio of aniline and monomer PAMPS unit is 1: 1) was mixed for 6 hours to bind and establish electrostatic equilibrium between positively charged aniline molecules (pKa 4.63) and negatively charged sulfo groups of the polymer (pKa 0.7) at a temperature of 20 ° C. Then, the polymerization reaction was initiated by adding 300 mg of the laccase from Trametes hirsuta fungus immobilized on carboxymethyl cellulose to the reaction solution. The synthesis of the polymer was carried out for 24 hours at room temperature with constant stirring. The formation of an interpolymer electrically conductive complex of polyaniline (PANI) and PAMPS was judged by the color change of the solution. After the immobilized laccase is introduced into the reaction mixture, the solution first turns blue (the formation of an emeraldine base) and then turns dark green, which indicates the formation of a polyaniline salt. After the completion of the aniline polymerization reaction on a polysulfonic acid matrix, the reaction mixture was centrifuged, the precipitate of immobilized laccase was separated, and the supernatant, which is an aqueous suspension of particles of the PANI / PAMPS polyaniline electrically conductive complex, was dialyzed against bidistilled water to remove components of the non-aniline buffer solution low molecular weight aniline oligomers. The electrical conductivity of the dried PANI / PAMPS sample, measured by the standard two-point method, was 1.2 mS / cm. On the UV-visible spectra of the aqueous dispersion of nanoparticles of the PANI / PAMPS interpolymer complex, there are absorption bands in the region of 420 nm and 780 nm, which corresponds to the electrically conductive PANI in the form of an emeraldine salt. The laccase was immobilized as follows: 500 mg of granulated KM cellulose, with a specific capacity of 0.8 mg equivalent carboxyl groups per 1 g of carrier, previously washed from a suspension of small particles by decantation in water, was suspended in 5 ml of bidistilled water containing 35 mg Woodward reagent and was stirred at 5 ° C for 1 hour. The precipitate was separated by decantation and resuspended in 5 ml of distilled water containing 0.2 mg of Laccase Trametes hirsuta. The reaction mixture was stirred for 24 hours at 5 ° C. The precipitate was separated by centrifugation and washed with double-distilled water to remove excess unreacted laccase. The obtained immobilized laccase was used for the synthesis of polyaniline.

Example No. 2. The synthesis of polyaniline on a PAMPS matrix was carried out similarly to that described in example No. 1, but at pH 3.0.

Example No. 3. The synthesis of polyaniline on a PAMPS matrix was carried out similarly to that described in example No. 1, but at a temperature of 4 ° C.

Example No. 4. The synthesis of polyaniline on the PAMPS matrix was carried out similarly to that described in example No. 1, but the initial concentrations of aniline and the PAMPS monomer unit of 100 mM each at a temperature of 20 ° C were used.

Example No. 5. The synthesis of polyaniline on the PAMPS matrix was carried out similarly to that described in example No. 1, but the initial concentrations of aniline and the PAMPS monomer unit of 25 mM and 75 mM were used, respectively, at a temperature of 20 ° C and pH 3.5.

Example No. 6. The synthesis of polyaniline on the PAMPS matrix was carried out similarly to that described in example No. 1, but the initial concentrations of aniline and the PAMPS monomer unit were 75 mM and 25 mM, respectively, at a temperature of 20 ° C and pH 3.5.

Example No. 7. The synthesis of polyaniline on the PAMPS matrix was carried out similarly to that described in example No. 1, but in the absence of components of the buffer system at pH 3.5 and a temperature of 20 ° C, the concentration ratio of aniline and the monomer unit of PAMPS was 1: 1.2

Example No. 8. The synthesis of polyaniline on a PAMPS matrix was carried out similarly to that described in example No. 1, but immobilized laccase was isolated from the basidiomycete fungus Cerrena maxima.

Example No. 9. Polyaniline was synthesized on a PAMPS matrix as described in Example No. 1, but laccase from the basidiomycete Trametes hirsuta was immobilized on an aminated silochrome with a capacity of 0.6 mmol of amino groups per gram of sorbent using Woodward's reagent, carbodiimide, or glutaraldehyde as the crosslinking agent. In the latter case, Schiff base was reduced with sodium borohydride. In all cases, the technical result was achieved regardless of the laccase used and the method of immobilization of the enzyme.

Claims (1)

A method of producing an aqueous dispersion of an interpolymer complex of electrically conductive polyaniline and polysulfonic acid, comprising mixing aniline with polysulfonic acid under aerobic conditions in the presence of a laccase from a basidiomycete, characterized in that laccase from Trametes hirsuta, or Trametes pubescens, or Trametes ochracea, or Cerreniopsima fulvocinerea immobilized on a water-insoluble carrier, the process being carried out at a pH of 2.5-5.5 and a temperature of 4-35 ° C.