Field dependent switching angle of a columnar pyrene

Abstract

The switching behaviour of 1,3,6,8-tetrakis-((S)-2-(heptyloxy)propanoyloxy)pyrene was studied near room temperature in a monotropic columnar phase. The switching angle (optical tilt angle) increases linearly with the applied electric field from 0° to c. ± 10° at ± 0.35°/(V μm ⁻¹), then rapidly increases to its upper limit of 22°. The electric polarization is roughly proportional to the switching angle with a maximum value of 110nC cm⁻² at high field strengths. At field strengths up to 10 V μm⁻¹, a voltage and temperature independent 0 to 90 per cent switching time of c. 650 μs was measured. The observations are explained in terms of deformation and unwinding of an intracolumnar helix.