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Teixeira P.R.S.,Laboratorio Interdisciplinar Of Materiais Avancados Limav | Teixeira P.R.S.,Instituto Federal Of Educacao Ciencia E Tecnologia Do Piaui Ifpi | do Nascimento Marreiro A.S.,Instituto Federal Of Educacao Ciencia E Tecnologia Do Piaui Ifpi | Farias E.A.O.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | And 3 more authors.
Journal of Solid State Electrochemistry | Year: 2015

Hybrid and electroactive thin films containing microcrystalline cellulose (MC) or MC modified with a phosphate group (PC) were prepared in conjunction with polyaniline (PANI) and poly(vinyl sulfonic acid) (PVS) by the layer-by-layer technique. The MC or PC was dispersed in a PANI solution employed in the deposition process, and they produced the PVS/PANI(MC) and PVS/PANI(PC) films. The ultraviolet-visible (UV-Vis) studies showed that the same amount of material was adsorbed at each stage of deposition, characterizing the PVS/PANI(MC) and PVS/PANI(PC) films as self-regulated systems. The electrochemical measurements and cyclic voltammetry were carried out in a buffered medium and showed that PVS/PANI(PC) films present higher values of current density probably due to the self-doping process of polyaniline in the presence of phosphate cellulose. The PVS/PANI(PC) film was tested in the presence of chromium VI, and in this case, the presence of a third reduction peak at 0.38 V was observed, which is characteristic of this metal, demonstrating the possibility of PVS/PANI(PC) as an active layer in the development of sensors for monitoring groundwater springs. © 2015, Springer-Verlag Berlin Heidelberg.


Farias E.A.O.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | Dionisio N.A.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | Quelemes P.V.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | Leal S.H.,Federal University of ABC | And 6 more authors.
Materials Science and Engineering C | Year: 2014

Composites prepared from polyaniline (PANI) and the ceramic technology of titanium dioxide (TiO2) have been proposed, however, the interaction of these materials with greater control of molecular arrangement becomes attractive in order to achieve properties not previously described or yet the optimization of those already reported. Therefore, in this study, thin hybrid films made of polyaniline (PANI), a conductive polymer, and the technological ceramic, titanium dioxide (TiO2), were prepared by the layer-by-layer (LbL) self-assembly technique. The films were characterized by cyclic voltammetry (CV), UV-VIS spectroscopy and atomic force microscopy (AFM). Aiming to improve the dispersion of the ceramic in the polymer matrix, the commercial surfactant, cetyl trimethylammonium bromide (CTAB), was used in the formation of the films. The best condition of deposition was found showing synergic interactions between the conjugated materials. The antibacterial activity of the PANI(TiO2)/CTAB films was studied and the obtained results suggest their use as antimicrobial coatings. © 2013 Elsevier B.V. All rights reserved.


De Oliveira Farias E.A.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | Dos Santos M.C.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | De Araujo Dionisio N.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | Quelemes P.V.,Nucleo de Pesquisa em Biodiversidade e Biotecnologia | And 5 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2015

This paper proposes a new application for natural polysaccharides (agar and carrageenan), both extracted from the cell wall of red seaweeds. Thin films were prepared by the Layer-by-Layer (LbL) self-assembly technique onto ITO (tin-doped indium oxide), where the polysaccharides of interest were deposited in layers alternating with polyaniline (PANI). The films developed were characterized by cyclic voltammetry (CV), ultraviolet-visible spectroscopy (UV-vis) and atomic force microscopy (AFM). Results showed the presence of agar as well as carrageenan, which improves the electrochemical stability of the conducting polymer in an acid medium. The interactions at the molecular level between PANI and the biopolymers affected the most appropriate sequence of deposition as employed in the process of material immobilization and also influenced the resulting morphology. Among the films studied, the most promising system as regards electrochemical measurements was the ITO/agar/PANI system, which was subsequently employed in the electrochemical detection of chromium (VI). ©2015 Published by Elsevier B.V.

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