Analysis of Liquid Crystal Phase Behavior and Morphology via Polarized Optical Microscopy in Standard and Surface Aligned Observation Cells

Abstract

As the applications of liquid crystals continue to expand within the worlds of electronic displays, soft robotics, and elsewhere, understanding the phase behaviors and morphologies of liquid crystal systems has become increasingly in demand. One may gain insight into these characteristics by analyzing liquid crystal systems of varied chemical structures and lengths, across a range of analytical methods like polarized optical microscopy and scanning electron microscopy. Since no single analytical method can provide a holistic picture of liquid crystal phase behavior and morphology, expanding the scope of polarized optical microscopy by constructing aligned observation cells to observe monodomain liquid crystal alignment was a goal. In this work, liquid crystal monomers of varied molecular structures were successfully synthesized, and aligned observation cells were constructed so that successful monodomain alignment was observed through polarized optical microscopy. Moreover, evidence of organizationally complex dark conglomerate B4 phases was observed with polarized optical microscopy. Small scale structures, characterized by these phases, like nanocylinders, were then successfully imaged via scanning electron microscopy, pointing toward further analysis of liquid crystal systems of high complexity.