Document Type

Article

Publication Date

5-1-1996

Published In

Physical Review E

Abstract

The highly chiral compound S,S-4 ''-(methylbutyl)phenyl-4'-(methylbutyl) biphenyl carboxylate (S,S-MBBPC) undergoes a continuous supercritical evolution from the isotropic (I) phase to the third blue phase (BPI III). Mixtures of S,S-MBBPC and its racemate have been studied with high-resolution calorimetry capable of quantitative latent heat determinations and with optical activity measurements. Both experiments indicate that the first-order BP III-I transition line ends at a critical point when the chiral mole fraction X(c) similar or equal to 0.45. Analysis of C-p and optical activity data for the near-critical mixture with X = 0.45 indicates mean-field behavior instead of the theoretically predicted Ising fluctuation behavior, which would be analogous to that at the liquid-gas critical point of a simple fluid. It is speculated that the Ginzburg criterion can explain this mean-field behavior since the critical regime may be too small for experimental observation, as is the case for almost all Smectic-A -Smectic-C transitions.

Comments

This work is freely available courtesy of the American Physical Society.

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