Optical signals of uniaxial and biaxial cholesteric lyotropic phases

Autor(es)

Braga, W. S. ; Santos, O. R. ; Kimura, N. M. ; Simoes, M. ; Palangana, A. J.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MOLECULAR LIQUIDS; v. 354, p. 5-pg., 2022-03-11.

Resumo

Lyotropic cholesteric liquid crystalline phases were prepared by doping the ternary mixture of potassium laurate eth KL/decanol (DeOH)/ deuterium oxide (D2O) with brucine sulphate, in two different concentrations. Using the variation of the average color in a heating cycle, with and without the insertion of compensator a gypsum plate (1 lambda), in the light path, the optical signal of the cholesteric phases Ch(D)(-)& nbsp;(Ch(C)(+) ) was confirmed as being negative(positive). When the biaxial cholesteric phase (Ch(B)) is between two uniaxial phases (Ch(D) -Ch(B)-Ch(D)) or (Ch(D) -Ch(B) -Ch(C)), the sign of the ChB phase depends on the uniaxial phase in its vicinity. In the case (Ch(D)(-)-Ch(B)-Ch(D)(-), the phase Ch(B) has a negative optical signal (Ch(B)(-)) across the domain. However, if the ChB phase is between uniaxial cholesteric phases of opposite optical signals, it cannot have just one signal, but must have a change at some point in the biaxial domain showing (Ch(D)(-)-Ch(B)-Ch(B)(+)-Ch(C)(+)) phase sequence.(c) 2022 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 14/50983-3 - INCT 2014: fluidos complexos
• Beneficiário: Antonio Martins Figueiredo Neto
• Modalidade de apoio: Auxílio à Pesquisa - Temático