화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.366, 2577-2586, 2001
The flexoelectric behaviour of a hypertwisted chiral nematic liquid crystal
The flexoelectric behaviour of a hypertwisted chiral nematic bimesogenic liquid crystal is presented. Through detailed electro-optic measurements, with particular emphasis on the switching properties, we demonstrate remarkably high optical axis tilt angles. The material studied possessed a room temperature nematic phase and aligned easily on cooling under the application of a moderate electric field. Switching times of the order of 500 mus and contrast ratios of 90:1 are readily achieved. The tilt angles, measured using the rotating analyser technique, were found to be practically temperature independent and linear with the applied field. Tilt angles of 22.5 degrees were obtained with moderate applied fields of 9.4 V/mum whilst fields of 25 V/mum yielded tilt angles of 45 degrees. We believe these are the highest tilt angles ever recorded for such fields.