caa a22 4500 605466386 CHVBK 20210128100307.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s00397-015-0850-2 doi (NATIONALLICENCE)springer-10.1007/s00397-015-0850-2 Shear viscosity and rheology of ternary and quaternary lyotropic liquid crystals in discotic and calamitic nematic phases [Elektronische Daten] [Celso Risi, A. Figueiredo Neto, Paulo Fernandes, Anderson Sampaio, Erol Akpinar, Marcus Santos] We report rheological studies of micellar nematic phases of potassium laurate/ decanol/ water mixtures with and without addition of salt (K2SO4) at a fixed temperature of 20 ∘C. Using a cone-plate rheometer, we verified that the ternary mixture (i.e., without salt) exhibiting the discotic (N D ) nematic phase showed only a slight pseudo-plastic (or shear-thinning) behavior. In contrast, a pronounced pseudo-plastic effect was observed in the N D phase of the quaternary samples. On the other hand, all the N C samples (salted or unsalted) showed a quasi-Newtonian behavior. In addition, we have made viscosity measurements using a (variation of a) rotating Couette flow viscometer. Finally, we also performed density measurements, using a density cell attached to the viscometer. Our results showed a contrasting behavior between the two types of nematic phases in two aspects. Firstly, regarding the ternary samples only, the apparent viscosity η at moderate shear rates was lower in the N C than in the N D phase. The second aspect, regarding both ternary and quaternary samples, is that η in the N D phase dramatically increased as the salt concentration increased, while in the N C phase η was quite insensitive to the addition of salt. In order to analyse the results, we have used two different theoretical frameworks, namely the nematodynamics in the first aspect and the classical theory of electrolyte solutions in the second one. Springer-Verlag Berlin Heidelberg, 2015 Lyotropic liquid crystal nationallicence Micelles nationallicence Viscosity nationallicence Risi Celso Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil aut Figueiredo Neto A. Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil aut Fernandes Paulo Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil aut Sampaio Anderson Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil aut Akpinar Erol Arts and Sciences Faculty, Department of Chemistry, Abant Izzet Baysal University, 14280, Bolu, Turkey aut Santos Marcus Instituto de Física, Universidade de Brasília, 70919-970, Brasília, DF, Brazil aut Rheologica Acta Springer Berlin Heidelberg 54/6(2015-06-01), 529-543 0035-4511 54:6<529 2015 54 397 https://doi.org/10.1007/s00397-015-0850-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-015-0850-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Risi Celso Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Figueiredo Neto A. Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Fernandes Paulo Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil aut NATIONALLICENCE 700 1- Sampaio Anderson Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil aut NATIONALLICENCE 700 1- Akpinar Erol Arts and Sciences Faculty, Department of Chemistry, Abant Izzet Baysal University, 14280, Bolu, Turkey aut NATIONALLICENCE 700 1- Santos Marcus Instituto de Física, Universidade de Brasília, 70919-970, Brasília, DF, Brazil aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/6(2015-06-01), 529-543 0035-4511 54:6<529 2015 54 397