Optical Properties of Cholesteric Liquid Crystal Elastomer Film

A series of liquid crystal elastomer (LCE) films (ABC films) were prepared by polymerization of polymethylhydrosiloxane (PMHS), liquid crystal (LC) monomer cholesterol 4-(allyloxy) benzoate (M B ) and cross-linking agent 4'-(undec-10-enoyloxy)-[1,1'-biphenyl]-4-yl dodec-11-enoate (M C ) . The chemical structures and LC properties of the monomers and polymers were characterised by Fourier Transform Infrared Spectrometer (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), polarized optical micrograph (POM) and X-ray diffractometer (XRD). M B is a cholesteric LC and M C is a smectic LC. The ABC films are cholesteric LCEs. The temperature at which 5% weight loss occurred for the ABC films are around 300 °C. The glass transition temperature of ABC films increases with the increase of LC monomer M B content. The ABC films have a strong absorption around 200-330nm in the ultraviolet (UV) region, and the absorption range does not change with temperature.