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Transparent nematic phase in a liquid-crystal-based microemulsion

Nature volume 409, pages 321325 (18 January 2001) | Download Citation

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Abstract

Complex fluids1,2 are usually produced by mixing together several distinct components, the interactions between which can give rise to unusual optical and rheological properties of the system as a whole. For example, the properties of microemulsions (composed of water, oil and surfactants) are determined by the microscopic structural organization of the fluid that occurs owing to phase separation of the component elements. Here we investigate the effect of introducing an additional organizing factor into such a fluid system, by replacing the oil component of a conventional water-in-oil microemulsion with an intrinsically anisotropic fluid—a nematic liquid crystal. As with the conventional case, the fluid phase-separates into an emulsion of water microdroplets (stabilized by the surfactant as inverse micelles) dispersed in the ‘oil’ phase. But the properties are further influenced by a significant directional coupling between the liquid-crystal molecules and the surfactant tails that emerge (essentially radially) from the micelles. The result is a modified bulk-liquid crystal that is an ordered nematic at the mesoscopic level, but which does not exhibit the strong light scattering generally associated with bulk nematic order2: the bulk material here is essentially isotropic and thus transparent.

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Acknowledgements

We thank M. Takahashi for DSC measurements. H.T. is also grateful to T. C. Lubensky, E. M. Terentjev and S. Zumer for valuable discussions.

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Author notes

    • Jun Yamamoto

    Present address: Yokoyama Nano-structured Liquid-crystal Project, Tsukuba 300-2635, Japan.

Affiliations

  1. Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 , Japan

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Correspondence to Hajime Tanaka.

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https://doi.org/10.1038/35053035

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