Static and Dynamic Light Scattering Near the Liquid Crystalline Blue Phase III – Isotropic Liquid Critical Point

Static and dynamic light scattering measurements, all using circularly polarized light, are used to investigate the third blue phase to isotropic liquid critical point in a mixture of S, S–$4''$(methylbutyl)phenyl–$4'$–(methylbutyl)biphenylcarboxylate (S,S-MBBPC) and its racemate. The intensity of light scattering and the relaxation time for the most strongly fluctuating chiral mode are found to be significantly greater than in a supercritical mixture of S,S-MBBPC. While the increase is substantial, there is no indication that any true divergence in these quantities is present. The results can qualitatively be explained by the simple phenomenological theory of Lubensky and Stark [3], which places this transition in the same universality class as the liquid-gas transition.