Microscopic Textures of Micellar Cholesteric Liquid Crystals

Abstract

Cholesteric Phases of Micellar solutions consisting of potassium laurate (KL), l-de-canol and D₂O were studied as a function of the concentration of a chiral additive, brucine sulfate (BS). The molar ratio of decanol to KL was kept constant at 0.36:1, while the molar ratio of BS to KL was varied from zero to 0.016:l. The D₂O concentration was kept near 67% by weight. Microscopic observations of the textures and phase transitions were made on thin films. The phase diagram shows three different cholesteric phases, including a biaxial cholesteric phase. Reentrant cholesteric phases occur in a small concentration range. The transitions between the different cholesteric phases appear sharp but continuous. A new type of a cholesteric texture was found in the biaxial range. The texture seems to have a multiple twist and a three dimensional periodicity in the micellar alignment.

Keywords:

• Miceller cholesterics
• microscopic textures