Desenvolvimento de filmes mesoporosos de platina e de cobre em eletrodos e microeletrodos a partir de soluções líquido cristalinas de tensoativos

• Ano de defesa: 2015
• Autor(a) principal: Silva, Jessica Soares da [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Mesoporous electrode; Electrodeposition; Liquid crystals; Eletrodo mesoporoso; Eletrodeposição; cristais líquidos
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=2797650; http://repositorio.unifesp.br/handle/11600/47280

The lyotropic liquid crystal (LLC) are mixtures of solvents and amphiphilic molecules at a given temperature and relative concentration. Recent studies have been report the use of liquid crystalline solutions of non-ionic surfactants as a template for the production of electrodes with platinum mesoporous films. These electrodes have a high number of active sites per area, resulting in higher sensivity. Thus, this work aims the producing of mesoporous films of platinum and copper onto electrodes surfaces employing liquid crystalline mixtures. The study of these mixtures revealed the presence of hexagonal phase, at room temperature, in the Triton X - 100 / H2O / metallic ion system in the mass proportion of 45%, 45% and 10%, respectively. Platinum electrode (Ø = 1 mm) and microelectrodes (r = 50?m) were modified using the electrodeposition. The mesoporous platinum microelectrode showed a rugosity factor 668, and surface area 142 times greater than the polished platinum. The copper mesoporous microelectrode showed higher sensitivity, good repeatability, and enabled a large number of determinations for nitrate from a single deposition. The surfaces of these devices were analyzed by scanning electron microscopy and the results proved extremely rough surfaces and pores in the dimensions of 22 ± 7 nm and 45 ± 3 nm for platinium and copper, respectively. Therefore, this study demonstrated the use of a simple methodology that enabled the development of devices with high performance and low cost.