Fluorescence confocal polarizing microscopy of a fluorescent bent-core liquid crystal exhibiting polarization splay modulated (B7) structures and defects.

The B7 phases of bent-core molecules are polarization splay modulated fluid smectics that exhibit an unusually complex variety of exotic macroscopic structures, textures, and defects visible in polarized light microscopy. Herein we describe optical studies of these structures using fluorescence confocal polarizing microscopy (FCPM) and depolarized transmission optical microscopy to probe their organization in three dimensions. These experiments utilize recently reported fluorescent bent-core molecules designed to give strong polarized fluorescence. This new bent-core molecular family provides the means for probing a variety of bent-core phases and structures by using FCPM and multiphoton fluorescence nonlinear imaging techniques. Comparative textural analysis of the B7 structures obtained using different types of imaging and the corresponding structural models are discussed.