Estudo de filmes poliméricos de complexos a base de tiofeno8Schiff na construção de sensores eletroquímicos
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Data
2011-11-28
Autores
Pereira, Paulo Augusto Raymundo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os polímeros condutores a Base de Tiofeno-Schiff despontam como materiais alternativos para obtenção de eletrodos modificados com potencial aplicação em sensores químicos devido as excelentes propriedades condutoras e quelantes conferidas pelo poli-tiofeno e pelas Bases de Schiff, respectivamente. Neste trabalho, o complexo Tiofeno-Salen foi sintetizado e caracterizado por UV8Vis e FTIR, em seguida, monômeros complexos metálicos-tiofeno-Schiff foram sintetizados com a complexação de cátions metálicos de transição como Ni2+, Cu2+, VO2+, Fe3+, Ru3+ e Ce4+ e novamente caracterizados por UV8Vis e FTIR para comprovar a formação dos monômeros complexos metálicos-tiofeno-Schiff. Filmes poliméricos desses complexos metálicos foram obtidos pela técnica de eletropolimerização anódica e foram caracterizados eletroquimicamente por voltametria cíclica em solução aquosa. Verificou-se a influência de diversas variáveis experimentais tais como solvente, eletrólito de suporte, intervalo de varredura de potenciais, velocidade de varredura de potenciais, concentração do monômero e número de ciclos durante a etapa de eletropolimerização. Os substratos condutores utilizados na etapa de eletropolimerização foram o eletrodo de platina e o eletrodo de carbono vítreo, demonstrando a influência do substrato condutor na etapa de eletropolimerização e verificou-se que o eletrodo de platina apresentou maior eficiência de transferência eletrônica quando comparado ao eletrodo de carbono vítreo devido a natureza amorfa do carbono vítreo para esses filmes poliméricos estudados. Os eletrodos de platina modificados com esses filmes poliméricos foram também utilizados no estudo das suas propriedades eletroquímicas para a detecção de analitos de interesse analítico como L-dopa, ditionito, piridoxina, sulfito, nitrito, L-tiroxina e ácido gálico.
Conducting polymers of the Thiophene-Schiff Bases emerge as alternative materials to obtain modified electrodes with potential applications in chemical sensors due to the excellent conductive chelating properties conferred by the poly-thiophene and the Schiff Bases, respectively. In this work, the complex Thiophene-Salen was synthesized and characterized by UV-Vis and FTIR, then monomers complex metals8thiophene8Schiff were synthesized with the complexation of cations of transition metals such as Ni2+, Cu2+, VO2+, Fe3+, Ru3+ and Ce4+ and again characterized by UV-Vis and FTIR to confirm the formation of monomer-metal complexes with thiophene-Schiff. Polymer films of these complexes were obtained by anodic electropolymerization technique and were characterized electrochemically by cyclic voltammetry in aqueous solution. There was the influence of different experimental variables such as solvent, supporting electrolyte, potential scan range, potential scan rate, monomer concentration and number of cycles during the electropolymerization. The conductive substrates used in the electropolymerization were platinum electrode and a glassy carbon electrode, demonstrating the influence of the conductive substrate in the electropolymerization and was found that the platinum electrode showed a higher electron transfer efficiency when compared to the carbon electrode vitreous due to amorphous nature of glassy carbon for these polymer films studied. The platinum modified electrodes with these polymer films were also used to study their electrochemical properties for the detection of analytes of analytical interest as L-dopa, dithionite, pyridoxine, sulphite, nitrite, L-thyroxine and gallic acid presented higher apllication as chemical sensors for these analytes.
Conducting polymers of the Thiophene-Schiff Bases emerge as alternative materials to obtain modified electrodes with potential applications in chemical sensors due to the excellent conductive chelating properties conferred by the poly-thiophene and the Schiff Bases, respectively. In this work, the complex Thiophene-Salen was synthesized and characterized by UV-Vis and FTIR, then monomers complex metals8thiophene8Schiff were synthesized with the complexation of cations of transition metals such as Ni2+, Cu2+, VO2+, Fe3+, Ru3+ and Ce4+ and again characterized by UV-Vis and FTIR to confirm the formation of monomer-metal complexes with thiophene-Schiff. Polymer films of these complexes were obtained by anodic electropolymerization technique and were characterized electrochemically by cyclic voltammetry in aqueous solution. There was the influence of different experimental variables such as solvent, supporting electrolyte, potential scan range, potential scan rate, monomer concentration and number of cycles during the electropolymerization. The conductive substrates used in the electropolymerization were platinum electrode and a glassy carbon electrode, demonstrating the influence of the conductive substrate in the electropolymerization and was found that the platinum electrode showed a higher electron transfer efficiency when compared to the carbon electrode vitreous due to amorphous nature of glassy carbon for these polymer films studied. The platinum modified electrodes with these polymer films were also used to study their electrochemical properties for the detection of analytes of analytical interest as L-dopa, dithionite, pyridoxine, sulphite, nitrite, L-thyroxine and gallic acid presented higher apllication as chemical sensors for these analytes.
Descrição
Palavras-chave
Schiff bases, Electropolymerization, Modified electrode, Electrochemical behaviour, Chemical sensors, Química analítica, Polimerização, Schiff, Bases de, Eletroquimica, Filmes poliméricos, Sensores eletroquímicos, Eletropolimerização
Como citar
PEREIRA, Paulo Augusto Raymundo. Estudo de filmes poliméricos de complexos a base de tiofeno8Schiff na construção de sensores eletroquímicos. 2011. 176 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2011.