Polarizing microscopy, optical activity, reflection, and transmission measurements are used to determine the phase diagram for the blue phases of chiral 4’’-(2-methylbutylphenyl)-4’ -(2-methylbutyl)-4-biphenylcarboxylate (CE2) mixed with nonchiral 4-n-pentylbenzenethio-4’-n-heptyloxybenzoate (7¯S5). These mixtures exhibit a chirality higher than previously investigated. The phase diagram shows two new features: (1) blue phase II becomes unstable at high concentrations of the chiral component, and (2) blue phase III possesses a wider temperature range than blue phase I for the most chiral mixtures.

• Received 8 December 1986

DOI:https://doi.org/10.1103/PhysRevA.35.3959