| Since the late 1990s, the growth of research in the field of bent-core, or banana-shaped, liquid crystal mesogens and the "banana phases" formed by them, has been explosive. This relatively new field in thermotropic liquid crystals is still characterized by considerable uncertainty with respect to basic issues such as phase structure, and the relationship between molecular structure and phases. In particular, bent-core mesogens containing no Schiff bases in their molecular structure are relatively rare; and of these types of materials it is even more rare to find those that exhibit fluid smectic phases. Synclinic and anticlinic smectic C bent-core phases exhibiting spontaneous ferroelectricity (SMCSPF and SMCAPF respectively), while interesting in and of themselves due to their rarity, also possess potential utility in various applications, including analog phase modulation and non-linear optics, making them clear targets for investigation. It is the primary goal of this research to not only synthesize, using empirical design elements, these rare ferroelectric materials, but also seek to clarify the relationship between mesogen structure and phase behavior. Empirical data were refined into several design elements, which were then employed in the syntheses of materials and prediction of phase behavior with a relatively high degree of success. Moreover, materials exhibiting behavior not previously seen resulted from this work, including the first non-Schiff base B4 phase, the first fully enantiotropic B2-B1 antiferroelectric, and a de Vries bent-core mesogen. In addition, a number of novel and potentially useful anticlinic antiferroelectric tilted smectic materials (SMCAP A) were also obtained. |
