Nematic twin molecules and their application in cholesteric polymer networks

The synthesis of some novel nematic twin molecules is described. The insert ion of lateral substituents into the mesogenic core leads to glass forming materials. Cholesteric mixtures of nematic twins and a highly twisting sorb itol derivative were crosslinked by in-situ photopolymerization, whereby th e LC-structure of the monomers is permanently fixed in the network. UV/VIS spectra of the networks were recorded to investigate the dependence of the reflection wavelength from the content of chiral monomer and from the polym erization temperature.