Estudo da aplicação de filmes automontados de PAH/PEDOT: PSS em membranas de Nafion®

• Ano de defesa: 2013
• Autor(a) principal: Almeida, Tiago Pedroso de
• Orientador(a): Riul Júnior, Antonio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus Sorocaba
• Programa de Pós-Graduação: Programa de Pós-Graduação em Ciência dos Materiais - PPGCM-So
• Palavras-chave em Português: Filmes finos; Materiais nanoestruturados; Polímeros condutores; Layer-by-layer technique
• Palavras-chave em Inglês: Thin films; Nanostructured materials; Conducting polymers
• Área do conhecimento CNPq: ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA; ENGENHARIAS::ENGENHARIA MECANICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/8351

The present work aimed the fabrication of layer-by-layer nanostructured films of poly (allylaminehydrochloride) (PAH) and poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) onto Nafion® 212 membranes. Nafion® is the most used polyelectrolyte in proton exchange membranes (PEM) fuel cells due to its high proton conduction and good chemical stability at ambient temperature. Therefore, this polyelectrolyte presents some disadvantages due to the high methanol permeability when applied in Direct Methanol Fuel Cells (DMFC), reducing drastically the performance of the device. We studied how ultrathin films of PAH/PEDOT:PSS influence the methanol permeability and proton conduction in the LbL modified membranes. Results indicated good adherence of the LbL films onto Nafion® 212 and also good action as a methanol barrier. Nonetheless, together with the methanol blocking there was also a reduction in the proton conductivity, which occurs due to the LbL dipping deposition on both sides of Nafion® 212, trapping water inside the Nafion membrane, and certainly affecting the proton conduction. Moreover, the LbL film deposition might use some important chemical groups present at the Nafion® surface, used to water permeation, also affecting the proton permeation throughout the membrane.