Ferroelectric liquid crystals with extremely wide SmC* phase range

New series of ferroelectric liquid crystals containing four aromatic rings in the mesogenic core and the alkyllactate unit as a chiral centre were synthesized and investigated. All compounds have the SmA phase and the chiral SmC* phase in a very broad temperature range around 100 K. For the chlorine substituted materials the spontaneous polarization reaches the values of 110 - 150 nC/cm(2) at temperatures 50 K below the phase transition to the SmC* phase in contrast to the value of 60 nC/cm(2) for non-substituted compound. Similarly, increase due to the Cl substitution has been observed also for the values of spontaneous tilt angle.