Shear viscosity and rheology of ternary and quaternary lyotropic liquid crystals in discotic and calamitic nematic phases

Verfasser / Beitragende:
[Celso Risi, A. Figueiredo Neto, Paulo Fernandes, Anderson Sampaio, Erol Akpinar, Marcus Santos]
Ort, Verlag, Jahr:
2015
Enthalten in:
Rheologica Acta, 54/6(2015-06-01), 529-543
Format:
Artikel (online)
ID: 605466386
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024 7 0 |a 10.1007/s00397-015-0850-2  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00397-015-0850-2 
245 0 0 |a Shear viscosity and rheology of ternary and quaternary lyotropic liquid crystals in discotic and calamitic nematic phases  |h [Elektronische Daten]  |c [Celso Risi, A. Figueiredo Neto, Paulo Fernandes, Anderson Sampaio, Erol Akpinar, Marcus Santos] 
520 3 |a 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. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Lyotropic liquid crystal  |2 nationallicence 
690 7 |a Micelles  |2 nationallicence 
690 7 |a Viscosity  |2 nationallicence 
700 1 |a Risi  |D Celso  |u Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil  |4 aut 
700 1 |a Figueiredo Neto  |D A.  |u Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil  |4 aut 
700 1 |a Fernandes  |D Paulo  |u Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil  |4 aut 
700 1 |a Sampaio  |D Anderson  |u Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil  |4 aut 
700 1 |a Akpinar  |D Erol  |u Arts and Sciences Faculty, Department of Chemistry, Abant Izzet Baysal University, 14280, Bolu, Turkey  |4 aut 
700 1 |a Santos  |D Marcus  |u Instituto de Física, Universidade de Brasília, 70919-970, Brasília, DF, Brazil  |4 aut 
773 0 |t Rheologica Acta  |d Springer Berlin Heidelberg  |g 54/6(2015-06-01), 529-543  |x 0035-4511  |q 54:6<529  |1 2015  |2 54  |o 397 
856 4 0 |u https://doi.org/10.1007/s00397-015-0850-2  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
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950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00397-015-0850-2  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Risi  |D Celso  |u Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Figueiredo Neto  |D A.  |u Instituto de Física, Universidade de São Paulo, 05314-970, São Paulo, SP, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Fernandes  |D Paulo  |u Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Sampaio  |D Anderson  |u Departamento de Física, Universidade Estadual de Maringá, 87020-900, Maringá, PR, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Akpinar  |D Erol  |u Arts and Sciences Faculty, Department of Chemistry, Abant Izzet Baysal University, 14280, Bolu, Turkey  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Santos  |D Marcus  |u Instituto de Física, Universidade de Brasília, 70919-970, Brasília, DF, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Rheologica Acta  |d Springer Berlin Heidelberg  |g 54/6(2015-06-01), 529-543  |x 0035-4511  |q 54:6<529  |1 2015  |2 54  |o 397