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Cover Picture: On the Origin of the “Giant” Electroclinic Effect in a “De Vries”‐Type Ferroelectric Liquid Crystal Material for Chirality Sensing Applications (ChemPhysChem 6/2009)
Author(s) -
Kapernaum Nadia,
Walba David M.,
Korblova Eva,
Zhu Chenhui,
Jones Chris,
Shen Yongqian,
Clark Noel A.,
Giesselmann Frank
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200990020
Subject(s) - ferroelectricity , liquid crystal , condensed matter physics , tilt (camera) , phase transition , chirality (physics) , dielectric , materials science , coupling (piping) , order (exchange) , chemistry , physics , optoelectronics , chiral anomaly , geometry , composite material , mathematics , fermion , finance , quantum mechanics , nambu–jona lasinio model , economics
Abstract The cover picture shows characteristics of a new ‘de Vries’‐type ferroelectric liquid crystal in which the ferroelectric transition is an order–disorder transition where the directions of molecular tilt inside a smectic layer order into a certain direction. Since the rod‐like molecules (drawn as cylinders) are tilted in the paraelectric SmA* (with random tilt directions) as well as in the ferroelectric SmC* phase, the ferroelectric transition is connected with a rather weak contraction of the smectic layer thickness (even though the optical tilt θ reaches values of about 25°). On page 890, F. Giesselmann et al. show that this new ferroelectric material exhibits a remarkably weak temperature dependence of its giant electroclinic effect (the coupling between tilt and elelctric field) in the SmA* phase. The origin of this striking electroclinic effect is the co‐occurrence of a ‘de Vries’‐type ordering with a weak first‐order tilting transition.