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

Self-assembled Hybrid Films Of Phosphotungstic Acid And Aminoalkoxysilanes On Sio 2/si Surfaces

The present paper describes the influence of the chemical structure of two aminoalkoxysilanes: 3-aminopropyltriethoxysilane (APTS) and N-(3- (trimethoxysilyl)-propyl)-ethylenediamine (TSPEN) on the morphology of thin layer hybrid films with phosphotungstic acid (HPW), a Keggin heteropolyanion. X-ray photoelectron spectroscopy analyses indicated that both silane films showed protonated amine species interacting with the heteropolyanion by electrostatic forces as well as the presence of secondary carbamate anions. The hybrid films have different surface morphology according to atomic force microscopy analyses. The hybrid film with TSPEN forms flatter surfaces than the hybrid film with APTS. This effect is ascribed to higher flexibility and chelating ability of the TSPEN on adsorbed molecules. Ultrasonication effect on surface morphology of the hybrid film with APTS plays a fundamental role on surface roughness delivering enough energy to promote surface diffusion of the HPW heteropolyanions. This diffusion results in agglomerate formation, which corroborates with the assumption of electrostatic bonding between the HPW heteropolyanions and the protonated amine surface. These hybrid films could be used for electrochemical sensor design or to build photochromic and electrochromic multilayers. © 2011 Elsevier B.V. All rights reserved.520935743580Sagiv, J., (1980) J. Am. Chem. Soc., 102, p. 92Zhong, X., Yuan, R., Chai, Y.Q., Liu, Y., Dai, J.Y., Tang, D.P., (2005) Sens. Actuators, B, 104, p. 191Llorent-Martínez, E.J., García-Reyes, J.F., Ortega-Barrales, P., Molina-Díaz, A., (2005) Anal. Bioanal. 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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

Efeito do manejo do lençol freático na adaptação fisiomorfológica de duas espécies de trigo ao encharcamento Effect of the water table management in the morpho-physiological adaptation of two wheat species to waterlogging

Estudou-se o efeito de três manejos do lençol freático na indução de adaptações fisiomorfológicas dos trigos Triticum aestivum L. e Triticum durum L. à hipoxia, caracterizando e inferindo a influência relativa dos principais fatores físicos e biológicos interferentes. O experimento foi conduzido na ESALQ/USP, Piracicaba, SP, simulando-se ao máximo um meio físico/condição natural de uma várzea. Após a indução na fase vegetativa, através de períodos hipóxicos com duração progressiva, o grau de adaptação foi avaliado através de inundação permanente, incluindo o florescimento/formação de grãos. Observou-se: resposta diferenciada de exigência e/ou capacidade de extração de nutrientes entre as duas espécies; que a adubação foliar foi ineficiente para suprir as deficiências nutricionais da planta; que os manejos com curtos períodos de hipoxia induziram o trigo a adaptações fisiomorfológicas, porém não na intensidade ou eficiência de que resultassem parâmetros de produção em níveis adequados; enfim, que o manejo com o lençol freático mantido a 15 cm de profundidade durante todo o ciclo cultural foi o que propiciou melhor desempenho do trigo em cultivo sob encharcamento.<br>The effect of three different water table managements in the morpho-physiological adaptation to waterlogging of Triticum aestivum, L. and Triticum durum, L., and the relative influence of the main physical and biological interferance factors were studied. The trial was conducted at ESALQ/USP, Piracicaba, SP, under simulated conditions of a natural low land. After introduction of stress adaptation during the vegetative growth stage, while applying progressive times of hipoxics periods, there were observed different requirements and/or extraction capacities of nutrients between the two species; the fertilization on leaves was not enough to avoid nutritional deficiencies in wheat under hipoxia. The water table management used resulted in morpho-physiological adaptations, but not enough to reach adequate biometric parameters of productivity. The water table at a 15 cm depth throughout the crop cycle resulted in better performance