Cholesteric Liquid Crystals: Flow Properties, Thermo- and Electromechanical Coupling

From an experimental point of view the outstanding development in the area of Lehmann-type effects is clearly the demonstration of the transmembrane transfer of water molecules across chiral liquid crystalline monolayers located at an air-liquid interface by Tabe and Yokoyama (2003). Tabe and Yokoyama observed the formation of patterns such target waves due to the phase winding of the director orientation. They showed that changing the handedness of molecules of the compound leads to a rotation in the opposite direction and that the precession frequency associated with phase winding is proportional to the concentration difference. In addition, they found that the speed of precession is proportional to the inverse of the pitch, that is to the chiral strength. Finally achiral compounds showed no effects in the same geometry under the same external force.