Suppressing crystalline phases of liquid crystalline polymers

Thermotropic liquid crystalline (LC) materials rely on temperature-dependent reversible transitions between liquid crystalline (e.g. nematic) and isotropic states. However, many mesogens that demonstrate LC phases as monomers do not show LC behavior in the polymer form; instead, they form semi-crystalline polymers whose crystallinity can inhibit the desired material response to stimuli. In order to suppress the crystallinity of the LC polymers, copolymers of LC mesogens and non-LC spacers were prepared by first synthesizing macromonomers via azide-alkyne click chemistry. These macromonomers were then polymerized to form polymers with known mesogen-to-spacer ratios. Wide-angle X-ray scattering (WAXS) and thermal characterization of the resulting polymers was then undertaken to determine the impact of spacer content and polymer composition on the crystallinity and LC phase transition temperatures of these materials.