Suppression of Phase Transitions in a Confined Rodlike Liquid Crystal

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• 作者：Christos Grigoriadis ; Hatice Duran ; Martin Steinhart ; Michael Kappl ; Hans-Jürgen Butt ; George Floudas
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：November 22, 2011
• 年：2011
• 卷：5
• 期：11
• 页码：9208-9215
• 全文大小：998K
• 年卷期：0
• ISSN：1936-086X

文摘

The nematic-to-isotropic, crystal-to-nematic, and supercooled liquid-to-glass temperatures are studied in the liquid crystal 4-pentyl-4′-cyanobiphenyl (5CB) confined in self-ordered nanoporous alumina. The nematic-to-isotropic and the crystal-to-nematic transition temperatures are reduced linearly with the inverse pore diameter. The finding that the crystalline phase is completely suppressed in pores having diameters of 35 nm and below yields an estimate of the critical nucleus size. The liquid-to-glass temperature is reduced in confinement as anticipated by the model of rotational diffusion within a cavity. These results provide the pertinent phase diagram for a confined liquid crystal and are of technological relevance for the design of liquid crystal-based devices with tunable optical, thermal, and dielectric properties.