Medidas de índice de refração em uma fase nemática calamítica
Ano de defesa: | 2002 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Dissertação |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Estadual de Maringá
Brasil Programa de Pós-Graduação em Física UEM Maringá, PR Departamento de Física |
Programa de Pós-Graduação: |
Não Informado pela instituição
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Departamento: |
Não Informado pela instituição
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País: |
Não Informado pela instituição
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Palavras-chave em Português: | |
Link de acesso: | http://repositorio.uem.br:8080/jspui/handle/1/2708 |
Resumo: | The temperature dependence of the extraordinary/ordinary refractive indexes, density and optical birefringence are determined near the reentrant isotropic (IRE) - calamitic nematic (Nc) and Nc - isotropic (I) phase transitions in a lyotropic mixture of potassium laurate, decanol and water. This reentrant isotropic phase is verified by our experimental data and discussed in terms of thermal variation of the micellar shape anisotropy. It is also discussed the origin of negative optical birefringence of the calamitic nematic phase. The coefficient of electronic polarizability (Øi) is related to the density and extraordinary/ordinary refractive indexes measurements via the temperature derivative of the Vuks's equation. The results showed that near the IRE - Nc and Nc - I phase transitions the measured value of Øi was found to be about two order of magnitude smaller than that obtained for nematic MBBA system. From the experimental results it was found by means of the Vuks's equation that near the maximum optical birefringence in the range of NC phase the extraordinary coefficient of electronic polarizability (Øıı) is equal to the ordinary coefficient (Ø). |