Study on lyotropic liquid crystals of the 3-octyloxy-2-hydroxypropyl trimethyl ammonium bromide-<i style="mso-bidi-font-style: normal">n</i>-hexanolwater system

Abstract

Phase diagram of ternary system for 3-octyloxy-2-

hydroxypropyl trimethyl ammonium bromide (R₈TAB)-<i style="mso-bidi-font-style:normal">n</i>-hexanol- water has been investigated using turbidity titration method at 25 °C. Typical lyotropic liquid crystals (LLCs) of lamellar, hexagonal and cubic phases have been found in the system. The structure and the structure conversion have been

determined using polarizing-light microscope, ²H nuclear magnetic resonance (²H NMR) and differential scanning calorimetry (DSC). Experimental results show that with the enhancement of relative amount of water in a mixture maintaining mass ratio of R₈TAB to C₆H₁₃OH at 3:2, the phase transition is as follows: from mixed lamellar and hexagonal liquid crystals to mixed lamellar, hexagonal and cubic ones, then to single cubic one and finally to mixed hexagonal one and isotropic liquid phase.