Electronics and Nanotechnology, April 12-14, 2011, Kyiv, Ukraine 65 Carbon nanotubes and their composites with polyaniline: prospects of application Melezhik A.V., Dyachkova T.P., Filatova E.Yu., Tkachev A.G. Tambov State Technical University, Tambov, Russia, e-mail: [email protected] Abstract – Carbon nanotubes of the Taunit series and their composites containing 40-60% of polyaniline (PANI) have been synthesized. Due to high surface area (300-700 m2/g) of original nanotubes and electron donor- acceptor ability of PANI these materials are promising as electrodes of supercapacitors. Keywords – Carbon nanotubes, polyaniline, superapacitor. I. INTRODUCTION Carbon nanotubes (CNTs) were widely investigated as components of supercapacitors and batteries due to high surface area and electro- conductivity of CNTs. Besides this, CNTs and bulk structures formed by them have favorable pore size distribution in the mesopore range. Usually CNTs form agglomerates of different texture. Pore structure of agglomerates is determined by conditions of CNTs synthesis. Polyaniline is electron conducting and donor-acceptor polymer, which can be formed as layer on the surface of carbon nanotubes. CNTs modified with PANI have increased capacity as supercapacitor electrodes. II. MAIN PART We have obtained CNTs packed in loose bundles which can be interesting for electrochemical applications. These CNTs are: multiwalled CNTs with individual nanotube diameter of 8-15 nm, surface area 300 m 2 /g (Fig. 1) and few-walled CNTs Taunit-4 with individual nanotube diameter of 6 nm, surface area 600-700 m 2 /g (Fig. 2). Length of bundles for these nanotubes is up to 0.1 mm and more. Interesting peculiarity of Taunit-4 is its ability to form flexible sheets with bulk density of 0.1-0.4 g/cm 3 dependently on processing conditions. Fig. 1. Multiwalled (8-15 nm diameter) CNTs in bundles. Fig. 2. Few-walled (6 nm diameter) CNTs (Taunit-4) in bundles. The CNTs sheets can be used as electrode materials. To achieve uniform deposition of PANI on CNTs surface special regimes of deposition and CNTs pretreatment are needed. We have found that preliminary oxidative functionalization of CNT surface which resulted in chemical attachment of carboxyl groups favored adhesion of PANI coating to CNT surface (Fig. 3). Fig. 3. Dependence of PANI deposited mass on the CNTs carboxylation degree. Besides increasing mass content of the PANI attached carboxylation of CNTs increases chemical stability of PANI coating. TG analysis of the CNTs-PANI composites was studied. III . CONCLUSION Carbon nanotubes and CNTs-PANI nano- composites have been synthesized. These materials combine high surface area, electro- conductivity, chemical and thermal stability, which is favorable for application of these materials as electrode materials for supercapacitors.

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Page 1: Carbon nanotubes and their composites with polyaniline

Electronics and Nanotechnology, April 12-14, 2011, Kyiv, Ukraine 65

Carbon nanotubes and their composites with polyaniline: prospects of application

Melezhik A.V., Dyachkova T.P., Filatova E.Yu., Tkachev A.G. Tambov State Technical University, Tambov, Russia, e-mail: [email protected]

Abstract – Carbon nanotubes of the Taunit series and their composites containing 40-60% of polyaniline (PANI) have been synthesized. Due to high surface area (300-700 m2/g) of original nanotubes and electron donor-acceptor ability of PANI these materials are promising as electrodes of supercapacitors. Keywords – Carbon nanotubes, polyaniline, superapacitor.

I. INTRODUCTION Carbon nanotubes (CNTs) were widely

investigated as components of supercapacitors and batteries due to high surface area and electro-conductivity of CNTs. Besides this, CNTs and bulk structures formed by them have favorable pore size distribution in the mesopore range. Usually CNTs form agglomerates of different texture. Pore structure of agglomerates is determined by conditions of CNTs synthesis. Polyaniline is electron conducting and donor-acceptor polymer, which can be formed as layer on the surface of carbon nanotubes. CNTs modified with PANI have increased capacity as supercapacitor electrodes.

II. MAIN PART We have obtained CNTs packed in loose

bundles which can be interesting for electrochemical applications. These CNTs are: multiwalled CNTs with individual nanotube diameter of 8-15 nm, surface area 300 m2/g (Fig. 1) and few-walled CNTs Taunit-4 with individual nanotube diameter of 6 nm, surface area 600-700 m2/g (Fig. 2). Length of bundles for these nanotubes is up to 0.1 mm and more. Interesting peculiarity of Taunit-4 is its ability to form flexible sheets with bulk density of 0.1-0.4 g/cm3 dependently on processing conditions.

Fig. 1. Multiwalled (8-15 nm diameter) CNTs in bundles.

Fig. 2. Few-walled (6 nm diameter) CNTs (Taunit-4) in bundles. The CNTs sheets can be used as electrode materials.

To achieve uniform deposition of PANI on CNTs surface special regimes of deposition and CNTs pretreatment are needed. We have found that preliminary oxidative functionalization of CNT surface which resulted in chemical attachment of carboxyl groups favored adhesion of PANI coating to CNT surface (Fig. 3).

Fig. 3. Dependence of PANI deposited mass on the CNTs carboxylation degree. Besides increasing mass content of the PANI attached carboxylation of CNTs increases chemical stability of PANI coating. TG analysis of the CNTs-PANI composites was studied.

III. CONCLUSION Carbon nanotubes and CNTs-PANI nano-

composites have been synthesized. These materials combine high surface area, electro-conductivity, chemical and thermal stability, which is favorable for application of these materials as electrode materials for supercapacitors.