Optical Properties and Liquid-Crystalline Behaviors of Cyclosiloxane-based Oligomer Films

摘要

A series of liquid crystalline (LC) oligomer films (IP-VP) were prepared by use of cyclo(tetramethylhydrogeno)siloxane (CTMHS), and two different cholesteric monomers that possess ortho- or para-substituted benzene. The chemical structures, liquid-crystalline properties and optical properties of the synthesized materials were characterized by various experimental techniques. All the samples showed cholesteric phase with very wide mesophase temperature ranges. From IP to VP, the glass transition temperature and the isotropic temperature decreased slightly with increase of C2PB component in the polymer systems. The maximum reflection bands shift to long wavelength from IP to VP, suggesting the helical pitch become longer with more ortho-substituted benzene in the polymer systems