Induced antiferroelectric smectic-C-A* phase by doping ferroelectric-C* phase with bent-shaped molecules

Doping of the ferroelectric Sm-C* phase with bent-shaped molecules induces the antiferroelectric Sm-C-A* phase. The effect was observed by means of el ectro-optic and dielectric measurements in systems with weak interlayer int eractions in which the relative strength of anticlinic-synclinic order betw een molecules in adjacent layers is easily controlled by external factors. Fourier-transform infrared spectroscopy studies suggest that the bent-shape d molecules are not flat. They reorient upon the electric field-induced ant iferroelectric-ferroelectric transition to adopt a position in which the av erage direction of the carbonyl groups is in the smectic plane and a bendin g tip along the C-2 symmetry axis.