Preparation and properties of cholesteric network polymers based on liquid crystalline epoxides

Polyether network polymers with cholesteric superstructure are formed by the photochemically induced cationic copolymerisation of a nematic diepoxide with chiral epoxides. If a cholesteric superstructure is formed or not, depends on the temperature at which the photopolymerisation is carried out. The storage modulus is higher above T-G in samples with cholesteric superstructure. Optical rotations and vibrational circular dichroism spectra (VCD) depend strongly on the surface state of the substrates. From the VCD spectra it is concluded that the copolymerisation leads to different superstructures depending on the rub directions of the substrates.