<p>Electrochemical supercapacitors (ES) have become an attractive research interest in advanced power systems and found many applications as an energy storage device in number of areas. The fabrication of advanced electrodes with novel materials and new techniques plays a key part in determining the properties of ES. Conducting polymer polypyrrole (PPY) has been found to be a promising electrode material for ES due to its high pseudo-capacitance and good electrical conductivity.</p> <p>Polypyrrole (PPY) films were successfully obtained on stainless steel substrates by anodic electropolymerization. Anionic dopants such as 2,6-naphthalenedisulfonic acid disodium salt (NSA), chromotropic acid disodium salt (CHR) and gallic acid were used for the synthesis of PPY. The roles of additives in the electrodeposition process have been discussed. The deposition was performed galvanostatically or potentiodynamically and the electrochemical properties of PPY have been investigated and compared by using different characterization techniques.</p> <p>The comparison of the experimental data for NSA, CHR and gallic acid showed the influence of aromatic ring and OH groups on the capacitive behaviour of PPY films. Adherent PPY films were obtained from pyrrole solutions containing CHR as dopant. The specific capacitance (SC) increased with increasing pyrrole and dopant concentration in the solutions used for deposition. The PPY films prepared on stainless steel substrates by electropolymerization are promising electrode materials for ES.</p> / Master of Applied Science (MASc)

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-03-08T13:43:05Z No. of bitstreams: 2 Dissertação_Josiane A. Reis.pdf: 2107398 bytes, checksum: 8227d0b419e79cd9673a8f0c0f25f611 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-03-08T13:43:17Z (GMT) No. of bitstreams: 2 Dissertação_Josiane A. Reis.pdf: 2107398 bytes, checksum: 8227d0b419e79cd9673a8f0c0f25f611 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-08T13:43:17Z (GMT). No. of bitstreams: 2 Dissertação_Josiane A. Reis.pdf: 2107398 bytes, checksum: 8227d0b419e79cd9673a8f0c0f25f611 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-07-31 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / Concerned about sustainability, analytical chemists have developed chemical analysis procedures that aim to minimize the consumption of reagents and samples combined with the reduction of operating costs. Thus, in recent years, Digital Image Based (DIB) methods have often been used as an alternative to quantitative determinations in analytical chemistry, especially in samples of environmental interest, food, beverages and drugs. This work proposes a method based on digital images for the determination of methanol in alcoholic beverages. The proposed system uses a scanner to acquire images generated according to the RGB (Red, Green, Blue) system. The determination of methanol is based on an oxidation reaction of methanol. After the reaction an image is captured and a region of the image is selected for decomposition of the pixels into the values of the RGB components. The analytical curve is obtained by relating the logarithm of the ratio between the white solution standard and the norm of the calibration solutions as a function of the concentrations of these solutions. The methanol content was determined in (mL / 100 mL of anhydrous alcohol) in the samples of cachaça, brandy and liqueur of jambú, cupuaçu and cocoa. In order to illustrate the viability of the proposed method, analyzes were performed on seven beverage samples. The results were compared with those obtained by spectrophotometry and when applying the paired t-test it was found that there was no statistically significant difference between the results obtained with the two methods at a 95% confidence level. / Preocupados com a sustentabilidade os químicos analíticos têm desenvolvido procedimentos de análise química que visam minimizar o consumo de reagentes e amostras aliadas a redução de custos operacionais. Dessa forma, nos últimos anos os métodos Baseados em Imagens Digitais (DIB) têm sido frequentemente usados como uma alternativa para determinações quantitativas em química analítica, principalmente em amostras de interesse ambiental, alimentícios, bebidas e fármacos. Neste trabalho propõe se um método baseado em imagens digitais para determinação de metanol em bebidas alcoólicas. O sistema proposto usa um scanner para aquisição das imagens geradas de acordo com o sistema RGB (Red, Green, Blue). A determinação do metanol é baseada em uma reação de oxidação do metanol. Após a reação uma imagem é capturada e uma região da imagem é selecionada para decomposição dos pixels nos valores das componentes RGB. A curva analítica é obtida relacionando o logaritmo da razão entre a norma da solução do branco e a norma das soluções de calibração em função das concentrações dessas soluções. O teor de metanol foi determinado em (mL/ 100mL de álcool anidro) nas amostras de cachaça, aguardente, licor de jambú, cupuaçu e cacau. A fim de ilustrar a viabilidade do método proposto, foram realizadas analises em sete amostras de bebidas. Os resultados foram comparados com os obtidos por espectrofotometria e ao se aplicar o teste t emparelhado verificou-se que não há estatisticamente diferença significativa entre os resultados obtidos com os dois métodos para um nível de 95% de confiança.