Eletrodos combinados e flexíveis de grafite com híbridos de derivados de grafeno e poli(o-etoxianilina).
Data
2023-07-04
Autores
Carnaúba, José Hérelis Simão 
Orientadores
Simões, Fábio Ruiz
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O desenvolvimento de novos eletrodos, visando diferentes aplicações, é uma das inúmeras possibilidades de uso para o grafeno e seus derivados, tais como, o óxido de grafeno (GO) e o óxido de grafeno reduzido (rGO). Os polímeros condutores (CPs) também têm sido utilizados no desenvolvimento de eletrodos para diversas aplicações. Mais recentemente, a sinergia entre os híbridos de grafeno e CPs tem sido objeto de estudos em um grande número de publicações científicas, especialmente, em aplicações como dispositivos eletroquímicos como supercapacitores, sensores eletroanalíticos, células solares e sistemas de armazenamento de cargas. Nesse trabalho foram produzidos e caracterizados eletrodos de circuito impresso (SPE) flexível, baseados em resina alquídica e grafite e modificados com o polímero condutor poli(o-etoxianilina) POEA, bem como seus respectivos híbridos com GO e rGO. O GO foi produzido a partir da exfoliação química do grafite em solução pelo método de Hummers modificado e o rGO foi obtido a partir da redução do GO com ácido L-ascórbico (L-AA). Tanto a POEA quanto seus híbridos foram sintetizados a partir do monômero o-etoxianilina pelos métodos de polimerização química e de eletropolimerização. Os SPEs modificados foram caracterizados por FT-IR, microscopia eletrônica de varredura (SEM, do inglês “Scanning Electron Microscopy”), voltametria cíclica (CV) e espectroscopia de impedância eletroquímica (EIS). Os voltamogramas dos SPEs modificados, com POEA ou com os híbridos de POEA com derivados de grafeno, mostraram picos redox característicos da POEA. Os resultados de EIS mostraram uma redução significativa da resistência de transferência de carga (Rct) para o processo de oxirredução da POEA em meio ácido (HCl 1,0 mol L-1), devido a incorporação de GO e rGO para os híbridos de POEA-GO e POEA-rGO, respectivamente, com 2,5 % em massa em relação à tinta condutora (47,5% de grafite e 50% de resina alquídica e 2,5 % material modificador). Os SPEs modificados com os híbridos eletropolimerizado também tiveram os valores de Rct menores do que os SPEs modificados eletroquimicamente apenas com a POEA. Contudo, a presença de rGO mesmo em proporção muito baixa (aproximadamente 0,17% em relação à tinta) proporcionou uma diminuição de até 3x do valor de Rct, em relação à contraparte modificada apenas com POEA. Desta forma, acredita-se que o sinergismo de propriedades dos derivados de grafeno com a POEA se mostrou mais vantajoso na produção das tintas.
The development of new electrodes, targeting different applications, is one of the many possible uses for graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO). Conductive polymers (CPs) have also been used in the development of electrodes for various applications. More recently, the synergy between graphene hybrids and CPs has been the subject of studies in a large number of scientific publications, especially in applications such as electrochemical devices such as supercapacitors, electroanalytical sensors, solar cells and charge storage systems. In this work, flexible screen-printed electrodes (SPE) were produced and characterized, based on alkyd resin and graphite and modified with the conductive polymer poly(o-ethoxyaniline) POEA, as well as their respective hybrids with GO and rGO. GO was produced from the chemical exfoliation of graphite in solution by the modified Hummers method and rGO was obtained from the reduction of GO with L-ascorbic acid (L-AA). Both POEA and its hybrids were synthesized from o-ethoxyaniline monomer by chemical polymerization and electropolymerization methods. The modified SPEs were characterized by FT-IR, scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Voltammograms of the modified SPEs, with POEA or with POEA hybrids with graphene derivatives, showed redox peaks characteristic of POEA. The EIS results showed a significant reduction in the charge transfer resistance (Rct) for the redox process of POEA in an acid medium (1.0 mol L-1 HCl), due to the incorporation of GO and rGO for the hybrids POEA-GO and POEA-rGO, respectively, with 2.5 % by mass in relation to the conductive ink (47.5 % graphite and 50 % alkyd resin and 2.5 % modifier material). SPEs modified with electropolymerized hybrids also had lower Rct values than SPEs electrochemically modified with POEA alone. However, the presence of rGO even in a very low proportion (approximately 0.17% in relation to the ink) provided a decrease of up to 3 times in the Rct value, in relation to the counterpart modified only with POEA. In this way, it is believed that the synergism of properties of graphene derivatives with POEA proved to be more advantageous in the production of inks.
The development of new electrodes, targeting different applications, is one of the many possible uses for graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO). Conductive polymers (CPs) have also been used in the development of electrodes for various applications. More recently, the synergy between graphene hybrids and CPs has been the subject of studies in a large number of scientific publications, especially in applications such as electrochemical devices such as supercapacitors, electroanalytical sensors, solar cells and charge storage systems. In this work, flexible screen-printed electrodes (SPE) were produced and characterized, based on alkyd resin and graphite and modified with the conductive polymer poly(o-ethoxyaniline) POEA, as well as their respective hybrids with GO and rGO. GO was produced from the chemical exfoliation of graphite in solution by the modified Hummers method and rGO was obtained from the reduction of GO with L-ascorbic acid (L-AA). Both POEA and its hybrids were synthesized from o-ethoxyaniline monomer by chemical polymerization and electropolymerization methods. The modified SPEs were characterized by FT-IR, scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Voltammograms of the modified SPEs, with POEA or with POEA hybrids with graphene derivatives, showed redox peaks characteristic of POEA. The EIS results showed a significant reduction in the charge transfer resistance (Rct) for the redox process of POEA in an acid medium (1.0 mol L-1 HCl), due to the incorporation of GO and rGO for the hybrids POEA-GO and POEA-rGO, respectively, with 2.5 % by mass in relation to the conductive ink (47.5 % graphite and 50 % alkyd resin and 2.5 % modifier material). SPEs modified with electropolymerized hybrids also had lower Rct values than SPEs electrochemically modified with POEA alone. However, the presence of rGO even in a very low proportion (approximately 0.17% in relation to the ink) provided a decrease of up to 3 times in the Rct value, in relation to the counterpart modified only with POEA. In this way, it is believed that the synergism of properties of graphene derivatives with POEA proved to be more advantageous in the production of inks.