Fluorescent Columnar Liquid-Crystalline Polymers: Synthesis, Mesomorphic Behaviors and Tunable Emission Wavelengths^†

Fluorescent columnar liquid-crystalline polymers have attracted intensive attention due to their unique features that can be applied in many fields. However, the utilization of molecular engineering to achieve efficient fluorescence tuning has rarely been resolved. Herein, we report a series of liquid-crystalline polymers with α-cyanostilbene pendants attaching to polymethacrylate backbone by variant length ethylene glycol spacers, that assemble into hexagonal columnar mesophases and exhibit efficient fluorescence emission. Both the columnar ordering and the emission wavelength can be tuned just by altering the length of flexible spacers. With an elongation of the spacer, the columnar ordering and dimensions increased, and the fluorescence emission blue-shifted gradually. With good correlation of molecular design, columnar structure and fluorescence property, this study is expected to augment the understanding of spacer length influence in liquid-crystalline polymers and provide a guidance for the design and development of novel functional polymer materials.