New Achiral Non Symmetric Banana-Shaped Mesogens: Mesomorphic and Electro-Optical Properties

Abstract
The first series of achiral non symmetric banana-shaped mesogens has been synthesized. The mesophases observed for these compounds depend on the whole number of carbons in the alkyl chains (N). They were investigated by optical microscopy, calorimetry, X-ray diffraction experiments and electro-optical measurements. For intermediate and long chains (N ≥ 20) the liquid crystal phase is smectic (Sm?) and for shorter chains (N < 20) the mesophase appears to be columnar ordered (Col?). Yet the structure of neither one is fully resolved. Both phases exhibit a ferroelectric behaviour.