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http://hdl.handle.net/10400.21/661
Título: | An electro-rheological study of the nematic liquid crystal 4-n-heptyl-4'-cyanobiphenyl |
Autor: | Cidade, M. T. Leal, Catarina R. Patricio, Pedro |
Palavras-chave: | Electrorheology Liquid crystals 7CB Continuum theory |
Data: | 2010 |
Editora: | Taylor & Francis LTD |
Citação: | CIDADE, M. T.; LEAL, C. R.; PATRÍCIO, P. – An electro-rheological study of the nematic liquid crystal 4-n-heptyl-4'-cyanobiphenyl. Liquid Crystals. ISSN 0267-8292. Vol. 37, N.º 10 (2010), pp. 1305-1311. |
Resumo: | An experimental and theoretical study of the electro-rheological effects observed in the nematic phase of 4-n-heptyl-4'-cyanobiphenyl has been conducted. This liquid crystal appears to be a model system, in which the observed rheological behaviour can be interpreted by the Leslie-Ericksen continuum theory for low molecular weight liquid crystals. Flow curves are illustrated at different temperatures and under the influence of an external electric field ranging from 0 to 3 kV mm-1, applied perpendicular to the direction of flow. Also presented is the apparent viscosity as a function of temperature, over similar values of electric field, obtained at different shear rates. A master flow curve has been constructed for each temperature by dividing the shear rate by the square of the electric field and multiplying by the square of a reference value of electric field. In a log-log plot, two Newtonian plateaux are found to appear at low and high shear rates, connected by a shear-thinning region. We have applied the Leslie-Ericksen continuum theory, in which the director alignment angle is a function of the electric field and the flow field boundary conditions are neglected, to determine viscoelastic parameters and the dielectric anisotropy. |
Peer review: | yes |
URI: | http://hdl.handle.net/10400.21/661 |
ISSN: | 0267-8292 |
Aparece nas colecções: | ISEL - Física - Artigos |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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An electro-rheological study of the nematic liquid crystal 4-n-heptyl-4'-cyanobiphenyl_rep.pdf | 51,15 kB | Adobe PDF | Ver/Abrir |
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