| Abstract: | Liquid crystalline side group copolymers containing cholesteryl and S-(-)-chloropropionyloxybiphenyl groups were synthesized and investigated by size exclusion chromatography, 1H NMR spectroscopy, polarization microscopy, X-ray diffraction and differential scanning calorimetry. The spacer of the cholesteryl-containing side groups was changed by the substitution of two methylene groups by ether groups. The existence of a cholesteric phase on copolymerization of two monomers containing chiral tail groups, from which the homopolymers exhibit only smectic phases, could be observed. This cholesteric phase only exists over a narrow range of copolymer composition. The temperature dependence of the reflection wavelength for the cholesteric phase was determined. For the cholesteryl-containing homopolymer, an SA bilayer phase was observed, whereas the S-(-)-chloropropionyloxybi2 phenyl homopolymer showed a higher ordered SB phase below an SA monolayer phase. The layer periodicities of the SA phases of the copolymers depend on the composition. The substitution of two methylene groups of the spacer by ether groups led to disappearance of the cholesteric phase. Simultaneously, over a small range of copolymer composition a biphasic region was obtained. |
