Rotational reorganization of doped cholesteric liquid crystalline films.
In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric pitch. The direction of this reorganization is correlated to the sign of the change in helical twisting power of the dopant. The rotational reorganization of the liquid crystalline film was used to rotate microscopic objects 4 orders of magnitude larger than the bistable dopants in the film, which shows that molecular motors and switches can perform work. The surface of the doped cholesteric liquid crystalline films was found to possess a regular surface relief, whose periodicity coincides with typical cholesteric polygonal line textures. These surface features originate from the cholesteric superstructure in the liquid crystalline film, which in turn is the result of the presence of the chiral dopant. As such, the presence of the dopant is expressed in these distinct surface structures. A possible mechanism at the origin of the rotational reorganization of liquid crystalline films and the cholesteric surface relief is discussed.
Eelkema
Rienk
R
Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Pollard
Michael M
MM
Katsonis
Nathalie
N
Vicario
Javier
J
Broer
Dirk J
DJ
Feringa
Ben L
BL
D003460:Crystallization; D005449:Fluorenes / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D008853:Microscopy; D015394:Molecular Structure; D012399:Rotation; D013237:Stereoisomerism; D013499:Surface Properties; D013816:Thermodynamics
D005449:Fluorenes; C041509:fluorene