Gelling and the collective dynamics in ferroelectric liquid crystals.

Meziane, Rachid; Brehmer, Martin; Maschke, Ulrich; Zentel, Rudolf · Soft Matter · 2008

basic_science · Level V

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Abstract

Dielectric spectroscopy has been applied to investigate the dynamic behaviour of a ferroelectric liquid crystal in the smectic C* and smectic A phases confined in gel matrices of a fibre like (1D) or platelet like (2D) structure. These gel matrices were obtained from semicarbazide or bis-acylurea derivatives, which self assemble because of their H-bonding motif. The confinement strongly influences the magnitude of the spontaneous polarization and the collective fluctuations of the director detected as the Goldstone-mode. It is thus possible to detect gelation by dielectric spectroscopy. By this method it was possible to follow the destruction and restoration of the gel structure induced by the photochemical trans-cis isomerisation.