Effect of surfactant alkyl chain length on lyotropic uniaxial to biaxial cholesteric phase transitions

Autor(es)

Akpinar, Erol ^[1] ; Uygur, Nazli ^[1] ; Uyanik, Seda ^[1] ; Figueiredo Neto, Antonio Martins ^[2]

Afiliação do(s) autor(es)

^[1] Abant Izzet Baysal Univ, Fac Arts & Sci, Dept Chem, TR-14030 Golkoy, Bolu - Turkey

^[2] Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05508090 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: EUROPEAN PHYSICAL JOURNAL E; v. 42, n. 9 SEP 2019.
• Citações Web of Science: 0

Resumo

Some ionic surfactant-based lyotropic mixtures, exhibiting cholesteric phases, were prepared to investigate the effect of the surfactant alkyl chain length on a) uniaxial-to-biaxial phase transitions and b) stabilization of different cholesteric phases. Potassium alkanoates, KCx, (potassium undecanoate, KC11, potassium dodecanoate, KC12, and potassium tridecanoate, KC13) were chosen as the surfactant molecules. The lyotropic mixtures, which were composed of KCx/potassium sulfate (K2SO4)/decanol (DeOH)/water/brucine, where brucine is a chiral dopant molecule, were studied. Partial phase diagrams were constructed to show how the surfactant alkyl chain affects the phase topologies in the phase diagrams. It was observed that the presence of a longer surfactant alkyl chain in the mixture favors the stabilization of the larger discotic cholesteric, Ch(D), and cholesteric biaxial, Ch(B), phase domains. The phase transitions from the uniaxial cholesteric to biaxial cholesteric phase were shifted to lower temperatures. (AU)

• Processo FAPESP: 16/24531-3 - Propriedades estruturais e biofísicas de lipoproteínas nativa e modificada
• Beneficiário: Antonio Martins Figueiredo Neto
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/50983-3 - INCT 2014: fluidos complexos
• Beneficiário: Antonio Martins Figueiredo Neto
• Modalidade de apoio: Auxílio à Pesquisa - Temático