High-Temperature Enantiomeric Glassy Liquid Crystals with Exclusive Cholesteric Mesomorphism

Glassy liquid crystals are a unique class of materials that can preserve their spontaneously ordered liquid crystalline state upon cooling through the glass-transition temperature. Cholesteric glassy liquid crystals (ChGLCs), in particular, are attractive for their selective reflection and circular polarization properties, and core-pendent ChGLCs display high morphological stability and exclusive mesomorphism over a broad temperature range. An enantiomeric pair of core-pendent ChGLCs was prepared following a deterministic synthesis route, allowing for both enantiomers to be scaled up and purified at the gram-level. The ability to process these compounds into well-ordered, nm- and mu m-thick films with glassy, monodomain cholesteric structures is demonstrated. Processed films exhibit a photonic band gap structure that splits unpolarized incident light into circularly polarized transmitted light of one handedness and circularly polarized reflected light of the opposite handedness. Mixing enantiomers at different stoichiometric ratios alters the cholesteric structure, thereby tuning the wavelength of reflection from the near-UV to the mid-IR. Moreover, glass transition temperatures and clearing temperatures of enantiomeric mixtures are independent of the mixing ratio, enabling the design and fabrication of durable circular polarizers, notch filters, and polarization control devices across different spectral regions.