Carbon Felt/Carbon Nanotubes/Pani as pH Sensor
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1018-EE14-10
Carbon Felt/Carbon Nanotubes/Pani as pH Sensor Glaucio Ribeiro Silva1, Elaine Yoshiko Matsubara2, Paola Corio3, Jose Mauricio Rosolen2, and Marcelo Mulato1 1 Physics and Mathematics, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto-SP, CA, 14040-901, Brazil 2 Chemistry, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto-SP, CA, 14040-901, Brazil 3 Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, CA, 05508-900, Brazil
Abstract This work proposes the use of the composite carbon felt/carbon nanotube/Polyaniline as an alternative for applications as a pH sensor device. The carbon felt/carbon nanotube is an electronic conductivity material that was obtained from polymer felt (poliacrilonitrile felt) using oxidation and carbonization processes. The cup-stacked and bamboo-like tubes were grown on the fibers of carbon felt by chemical vapor decomposition method. The sensor was obtained by incorporating polyaniline (Pani) on the nanotubes present on the fibers of carbon felt/carbon nanotubes composite. The measuring process uses an EGFET (Extended Gate Field Effect Transistors) configuration, which is a derivation of the ISFET (Ion Sensitive Field Effect Transistor) – that is basically a chemical semiconductor sensor. The drain-current versus sourcedrain voltage is presented for varying pH concentrations from 2 up to 12.
Introduction Carbon nanotubes (CNTs) have attracted the attention and interest of researchers of many fields because of their unique physical, chemical, electronic, and mechanical properties [1]. CNTs exhibit very good adsorption properties because they have high specific surface area and a nanoscaled structure that provides a large number of sites for reactions, thus leading to a high sensitivity. They have been found to be useful in many different applications, such as field emission displays, supercapacitors, batteries, hydrogen storage, tools in nanotechnology, chemical sensors, electronic devices, polymeric composites, and so forth [2, 3]. In the hundreds of studies carried out about CNTs, it is possible see that this material is an excellent support to several kinds of chemical species since it can be metallic or semiconductor, and can be submitted to several types of chemical and thermal treatments. However, for many of the mentioned technological applications, CNTs are also needed as electrodes, and carbon nanotubes/carbon felt composites (CNTs/felt) appears as interesting candidates for the development of several devices [4-6 ]. In this approach CNTs grow over an electronic conductivity three dimensional carbon felt substrate. This composite has good mechanical stability, is free of binder, can be submitted to several chemical treatments, and its geometry allows for the assembling of a large density of CNTs. In this context we have studied the possibilities of the composite CNTs/felt and polyaniline in the conducting emeraldine salt form (PANI) as EGFET sensor for pH detection. The choice of PANI is justified because of its excelle
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