The smectic layer spacing of a nonfluorinated ferroelectric liquid crystal (FLC) compound with almost no shrinkage and only minor tendency to form zigzag defects was characterized by small angle x-ray diffraction. The material lacks a nematic phase. The smectic-A*-smectic-C* phase transition was studied by measuring the thermal and electric field response of the optical tilt and the electric polarization. These properties are described very well by a Landau expansion even without introduction of a higher-order Theta(6) term. This result suggests a pure second-order phase transition far from tricriticality and differs considerably from the typical behavior of the A*-C* transition in most FLC materials.

In this work, the liquid crystal (S)-2-methylbutyl-[4'-(4' '-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2')-benzoyl)-propionyl)]-propionate (ZLL 7/*) was investigated by means of 13C NMR spectroscopy. This compound has a very peculiar mesomorphic behavior, showing the following phases: paraelectric SmA, ferroelectric SmC*, antiferroelectric SmC*A, re-entrant ferroelectric SmC*re, and ferroelectric hexatic Sm*HEX. The structural and orientational ordering properties of ZLL 7/* have been determined by exploiting the nuclear chemical shielding properties of 13C. To this aim, solid-state NMR techniques such as CP, SPINAL-64, and SUPER have been used in combination with DFT calculations. The agreement between experimental and in vacuo DFT shielding parameters appears to be satisfactory. The orientational order parameters obtained from the 13C shielding analysis have been discussed, taking into account different data analysis approaches and comparing them to those previously obtained from an independent 2H NMR study.