Data/hora: 22/06/2024 19:40:55

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 22/12/1999
Data da última atualização: | 02/07/2013
Autoria: | MALMONGE, J. A.; CAMPOS, M. S. de; MATTOSO, L. H. C.
Afiliação: | UNESP-Campus de Ilha Solteira; EMBRAPA-CNPDIA.
Título: | Absorption spectra of thin films of poly (o-methoxyaniline) irradiated by X-ray.
Ano de publicação: | 1997
Fonte/Imprenta: | In: ENCONTRO NACIONAL DE FISICA DA MATERIA CONDENSADA, 20., jun. 1997, Caxambu, MG. Resumos... Sao Paulo: Sociedade Brasileira de Fisica, 1997.
Páginas: | p. 317.
Idioma: | Inglês
Conteúdo: | The adsorption spectra of thim film of poly(o-methoxyaniline)(POMA), chemically synthesized, coated on quartz slides by dip coating from chloroform solution were measured as a function of irradiation dose. The UV-Vis Nir absorption analysis showed that unirradiated films(emeraldine base) presents two adsorption peaks at about 320nm and about 620nm assigned respectively to PI - PI and excitonic transitions. Upon irradiation, under 50% RH, we have observed that the intensity of the first (about 320nm) and second (about 620nm) peaks decrease while the intensity of two new peaks at 840nm and 430nm increase as function of irradiated dose. The same behavior is found when polyanilines are conventionally doped with inorganic acids. These two new absorption bands are consistent with an increase in the mobility of the charge carriers, i.e. doping of the polymers to the conductive regime. After 230kGy of radiation dose, we observed that absorption at 620 disappeared and the absorption at 840nm and 430nm had reached the maximum. The irradiated film was dedoped with 0.1M NH-4OH and its spectra of absorption was similar to unirradiated film. This same reversible process occurs to polyanilines doped with inorganic acid. The electrical conductivity measured by four probe increases from about 10E-10 S/cm (unirradiated films) to 10E-10 S/cm (irradiated fims). The conductivity reached for polyanilines was 0.5S/cm. We have also observed that conductivity increases as a function of radiation dose and humidity level, and that water plays an important role on doping induced by X-ray radiation.
Palavras-Chave: | filmes; polímeros.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (5727-1) - UPC - SP - -- - PROCI-97.00128 -  - 1997.00128 - DIS