J. Phys. II France
Volume 7, Numéro 11, November 1997
Page(s) 1683 - 1691
DOI: 10.1051/jp2:1997209
J. Phys. II France 7 (1997) 1683-1691

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

Upindranath Singh1, Peter J. Collings2, Christopher J. Booth3 and John W. Goodby3

1  Department of Physics, Mathematics, and Computer Science, University of the West Indies, Cave Hill, Bridgetown, Barbados
2  Department of Physics & Astronomy, Swarthmore College, Swarthmore, PA 19081, USA
3  Department of Chemistry, University of Hull, Hull HU6 7RX, UK

(Received 22 May 1997, accepted 4 July 1997)

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.

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