Origin of Lyotropic Liquid Crystalline Mesophase Formation and Liquid Crystalline to Mesostructured Solid Transformation in the Metal Nitrate Salt-Surfactant Systems


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Albayrak C., ÖZKAN N. , Dag O.

LANGMUIR, vol.27, no.3, pp.870-873, 2011 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 3
  • Publication Date: 2011
  • Doi Number: 10.1021/la1035932
  • Title of Journal : LANGMUIR
  • Page Numbers: pp.870-873

Abstract

The zinc nitrate salt acts as a solvent in the ZnX-C12EO10 (ZnX is [Zn(H2O)(6)](NO3)(2) and C12EO10 is C12H25(OCH2CH2)(10)OH) lyotropic liquid crystalline (LLC) mesophase with a drastic dropping on the melting point of ZnX. The salt surfactant LLC mesophase is stable down to -52 degrees C and undergoes a phase change into a solid mesostructured salt upon cooling below -52 degrees C; no phase separation is observed down to -190 degrees C. The ZnX-C12EO10 mesophase displays a usual phase behavior with an increasing concentration of the solvent (ZnX) in the media with an order of bicontinuous cubic(V-1)-2D hexagonal(H-1) - a mixture of 2D hexagonal and micelle cubic(H-1 + I)-micelle cubic(I)-micelle(L-1) phases. The phase behaviors, specifically at low temperatures, and the first phase diagram of the ZnX-C12EO10 system was investigated using polarized optical microscopy (POM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and Raman techniques and conductivity measurements.