Ferroelectric liquid-crystal systems containing 1R,4R-p-menthan-3-one derivatives as chiral additives

Liquid-crystal systems with an induced smectic C* phase composed of an achi ral matrix (a two-component eutectic mixture of phenyl benzoate derivatives ) and some 2-arylidene derivatives of 1R,4R-p-menthan-3-one with variable t erminal alkoxy group (the number of carbon atoms in the alkyl chain was n = 1, 4-8) as chiral additives are studied. The effect or the length of the t erminal alkyl group on the main parameters of the induced chiral smectic C* phase (spontaneous polarization, rotational viscosity, and the tilt angle of molecules in smectic layers theta) is analyzed. It is revealed that the values of the rotational viscosity acid the angle theta is lowest and highe st, respectively, for the system containing the chiral additive with n = 6. It is established that points at which extremal values of the parameters a re attained do not correspond to the conditions of similarity of the length s of the component molecules. It is shown that, in the ferroelectric compos itions under study, the volume dipole moment is formed from the effective d ipole moments of the molecules of the additive in accordance to the additiv e mechanism.