10 research outputs found
Preparação e caracterização óptica de filmes de poli(estireno sulfonados) dopados com neodímio
Systematic Evaluation of the Preparation of Conducting PANI/ABS Blends
ABSTRACT: Films of blended poly(acrylonitrile-butadiene-styrene) (ABS) and polyaniline (PANI) were produced by codissolving both components in a common organic solvent, which was then evaporated. The influence of the preparation conditions on the properties of the blends was analyzed by factorial design. The factors evaluated were the PANI content in the blend, the m-cresol to chloroform solvent ratio, the dopant used (dodecylbenzenesulfonic acid (DBSA) or camphor sulfonic acid) and its concentration, and the acrylonitrile content in the ABS. The responses analyzed were the flexibility and electrical conductivity of the blends. The results showed that the PANI content in the blend and the acrylonitrile content in the ABS were the major factors influencing both of the assessed responses. The dopant affected only the conductivity, DBSA being preferred for the development of more conductive PANI/ABS blends. The solvent ratio did not have any influence, owing to the uniform expanded coil conformation expected for PANI molecules at the studios ratios. After the best conditions had been established, a percolation threshold study was performed that pointed to a low threshold of 3 wt % PANI necessary in the blend, giving a flexible blend with a conductivity of 3 S/cm
Lead detection using micro/nanocrystalline boron-doped diamond by square-wave anodic stripping voltammetry
Monitoring heavy metal ion levels in water is essential for human health and safety. Electroanalytical techniques have presented important features to detect toxic trace heavy metals in the environment due to their high sensitivity associated with their easy operational procedures. Square-wave voltammetry is a powerful electrochemical technique that may be applied to both electrokinetic and analytical measurements, and the analysis of the characteristic parameters of this technique also enables the mechanism and kinetic evaluation of the electrochemical process under study. in this work, we present a complete optimized study on the heavy metal detection using diamond electrodes. It was analyzed the influence of the morphology characteristics as well as the doping level on micro/nanocrystalline boron-doped diamond films by means of square-wave anodic stripping voltammetry (SWASV) technique. the SWASV parameters were optimized for all films, considering that their kinetic response is dependent on the morphology and/or doping level. the films presented reversible results for the Lead [Pb (II)] system studied. the Pb (II) analysis was performed in ammonium acetate buffer at pH 4.5, varying the lead concentration in the range from 1 to 10 mu g L-1. the analytical responses were obtained for the four electrodes. However, the best low limit detection and reproducibility was found for boron doped nanocrystalline diamond electrodes (BDND) doped with 2000 mg L-1 in B/C ratio. (C) 2014 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)LAS INPE Natl Inst Space Res, BR-12227010 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, BrazilCNPq: 573797/2008-0FAPESP: 2008/57719-9FAPESP: 2012/00393-0Web of Scienc