<i>π</i> ‐Extended Viologen‐Based Lyotropic Chromonic Liquid Crystal Reactive Mesogen: Uniaxial Orientation and Photopolymerization for Transmittance and Color Controllable Electrochromic Smart Glass

Abstract

Abstract To advance the development of an electrochromic (EC) smart glass, a π ‐extended viologen‐based lyotropic chromonic liquid crystal ( π V‐LCLC) reactive mesogen (RM) is newly designed and successfully synthesized in this study. By extending the π ‐conjugation length of viologen, the π V‐LCLC RM forms a stable LCLC phase at room temperature and retains its chemical integrity during the EC reactions, exhibiting reversible transitions across three redox states: dication (D), cation‐radical (C), and neutral (N). A uniaxially oriented nanostructure is constructed on the macroscopic scale through shear‐coating and molecular self‐assembly. Subsequent photopolymerization of the uniaxially oriented π V‐LCLC film significantly enhances its mechanical and chemical stability while enabling polarization‐dependent transmittance and distinct color transitions. This newly developed π V‐LCLC RM facilitates the fabrication of energy‐efficient EC optical devices with tunable transmittance and multicolor modulation, and it is operable at a low voltage of 2.5 V.