Afm Studies Of Composite 16-mer Polyaniline Langmuir-biodgett (lb) Films

Atomic force microscopy (AFM) images of composite Langmuir-Blodgett (LB) films containing different weight percentages of cadmium stearate and 16-mer polyaniline are investigated. Upon increasing the amount of 16-mer polyaniline content in the composite, large globular structures with higher average roughness could be seen. © 1999 Elsevier Science S.A. All rights reserved.1011-3830831(1990) Langmuir-Blodgett Films, , G.G. Roberts (Ed.) Plenum Press, New YorkDhanabalan, A., Riul Jr., A., Oliveira Jr., O.N., (1998) Supramolecular Science, 5, p. 75. , and references thereinMacDiarmid, A.G., (1997) Synth. Met., 84, p. 27Dhanabalan, A., Riul Jr., A., Mattoso, L.H.C., Oliveira Jr., O.N., (1997) Langmuir, 13, p. 4882Riul Jr., A., Dhanabalan, A., Mattoso, L.H.C., De Souza, L.M., Ticianelli, E.A., Oliveira Jr., O.N., Thin Solid Films, , in pressSuwa, T., Kakimoto, M., Imai, Y., Araki, I., Iriyama, K., (1994) Mol. Cryst. Liq. Cryst, 225, p. 45Constantino, C.J.L., Dhanabalan, A., Pereira Da Silva, M.A., Cotta, M.A., Oliveira Jr., O.N., submitte

Characterization Of Langmuir-blodgett Films Of Parent Polyaniline

Conducting Langmuir-Blodgett (LB) films have been fabricated from parent polyaniline (PAni) which was doped with functionalized acids. In order to optimize experimental conditions for the formation of stable Langmuir monolayers and their subsequent transfer onto solid substrates, PAni was dissolved in ten different combinations of chloroform solutions. Use was made of camphor sulfonic acid, dodecyl benzene sulfonic acid, and toluenesulfonic acid, and of the solvents N-methyl pyrrolidine and m-cresol as processing agents. Because acidic subphases have been employed, as-deposited LB films were already doped, which was confirmed by the appearance of a polaronic band in the UV-Vis absorption spectra. The absorbance peak increases with the number of deposited layers indicating that a suitable multilayer buildup is accomplished. When analysed by atomic force microscopy, PAni LB films show a fibrillar structure with the fibril width ranging from ≈ 60 to 160 nm.284-285177180Cao, Y., Smith, P., Heeger, A.J., (1993) Synth. Met., 55-57, p. 3514Riul A., Jr., Mattoso, L.H.C., Mello, S.V., Telles, G.D., Oliveira O.N., Jr., (1995) Synth. Met., 71, p. 2067Mattoso, L.H.C., MacDiarmid, A.G., Epstein, A.J., (1994) Synth. Met., 68, p. 1Mattoso, L.H.C., Mello, S.V., Riul A., Jr., Oliveira O.N., Jr., Faria, R.M., (1994) Thin Solid Films, 244, p. 714Cheung, J.H., Rubner, M.F., (1994) Thin Solid Films, 244, p. 990Agbor, M.E., Petty, M.C., Monkman, A.P., Harris, M., (1993) Synth. Met., 55-57, p. 3789Punkka, E., Laakso, K., Stubb, H., Levon, K., Zheng, W.-Y., (1994) Thin Solid Films, 515-520, p. 243MacDiarmid, A.C., Epstein, A.J., (1994) Synth. Met., 65, p. 103Morgan, H., Taylor, D.M., Oliveira O.N., Jr., (1991) Biochim. Biophys. Acta, 1062, p. 149Cheung, J.H., (1993), Ph.D. Thesis, Massachusetts Institute of Technology, EUAMacDiarmid, A.G., Epstein, A.J., (1993) Brazilian Conf. on Polymers, p. 544. , São Paulo, Brazil, October Brazilian Polymer Association, São Carlos, BrazilMantovani, J.G., Warmack, R.J., Annis, B.K., MacDiarmid, A.G., Scherr, E., (1990) J. Appl. Polym. Sci., 40, p. 169

The use of an e-tongue for discriminating ethanol/water mixtures and determination of their water content

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThis paper discusses the applicability of an electronic tongue (e-tongue) based on capacitance measurements to determine the water content in ethanol. The e-tongue consisted of an array of interdigitated electrodes coated with ultrathin films of gallium nitrate and titanium dioxide, which were robust against attack by ethanol. Principal Component Analysis (PCA) was used to treat the capacitance data for discriminating ethanol/water mixtures even in cases with very small water contents. Discrimination is easier if the water added to ethanol contains ions, as is the case of tap water or if NaCl is added to the mixtures. With this e-tongue we were able to quantify the water content through a linear relationship between the first principal component (PCl) and the added water to the biofuel. Therefore, we have proven to be possible to measure the water content precisely, which is one of the major problems in ethanol biofuel adulteration nowadays. (C) 2016 Elsevier B.V. All rights reserved.This paper discusses the applicability of an electronic tongue (e-tongue) based on capacitance measurements to determine the water content in ethanol. The e-tongue consisted of an array of interdigitated electrodes coated with ultrathin films of gallium nitrate and titanium dioxide, which were robust against attack by ethanol. Principal Component Analysis (PCA) was used to treat the capacitance data for discriminating ethanol/water mixtures even in cases with very small water contents. Discrimination is easier if the water added to ethanol contains ions, as is the case of tap water or if NaCl is added to the mixtures. With this e-tongue we were able to quantify the water content through a linear relationship between the first principal component (PCl) and the added water to the biofuel. Therefore, we have proven to be possible to measure the water content precisely, which is one of the major problems in ethanol biofuel adulteration nowadays.230566570FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçãoSem informaçãoSem informaçãoAuthors thank UNIVALEM (SP, Brazil) for kindly supplying the anhydrous and hydrous ethanol and FAPESP, CAPES and CNPQ for the financial support. The authors also thank Prof. Osvaldo N. Oliveira Jr for revising the manuscript

Information visualization and feature selection methods applied to detect gliadin in gluten-containing foodstuff with a microfluidic electronic tongue

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESThe fast growth of celiac disease diagnosis has sparked the production of gluten-free food and the search for reliable methods to detect gluten in foodstuff. In this paper, we report on a microfluidic electronic tongue (e-tongue) capable of detecting trace amounts of gliadin, a protein of gluten, down to 0.005 mg kg(-1) in ethanol solutions, and distinguishing between gluten-free and gluten-containing foodstuff. In some cases, it is even possible to determine whether gluten-free foodstuff has been contaminated with gliadin. That was made possible with an e-tongue comprising four sensing units, three of which made of layer-by-layer (LbL) films of semiconducting polymers deposited onto gold interdigitated electrodes placed inside microchannels Impedance spectroscopy was employed as the principle of detection, and the electrical capacitance data collected with the e-tongue were treated with information visualization techniques with feature selection for optimizing performance. The sensing units are disposable to avoid cross-contamination as gliadin adsorbs irreversibly onto the LbL films according to polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS) analysis. Small amounts of material are required to produce the nanostructured films, however, and the e-tongue methodology is promising for low-cost, reliable detection of gliadin and other gluten constituents in foodstuff.9231964619652FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES2012/15543-72013/14262-72014/16789-52014/03691-7Sem informaçãoSem informaçãoThis work was supported by FAPESP (2013/14262-7), CNPq, CAPES, MCTI-SisNano (Brazil). F.M.S. thanks FAPESP Grant 2012/15543-7. A.R.Jr. thanks FAPESP (2014/03691-7) for financial support. D.S.C. thanks FAPESP (2014/16789-5) and Embrapa - Rede Agronano for support