Molecular rotational potentials in the SC* phase of binary ferroelectric liquid crystal mixtures

The spontaneous polarization and tilt angle have been measured as a function of temperature and concentration in the S_C* phase of four binary ferroelectric liquid crystal mixtures. The substances have been chosen in a way that different situations could be studied, for example mixtures of a chiral substance (P_s non-zero) with a non-chiral one (P_s = 0) and mixtures of chiral compounds with the same sign of P_s as well as with opposite signs. The results have been interpreted by means of a molecular rotational model and potentials associated with the tilt as well as with the chirality have been determined as a function of concentration.