X-ray investigations on liquid crystalline side chain polymers

X-ray investigations have been carried out on crystalline and smectic polymers with polysiloxane backbones and mesogenic side groups attached to the main chain by flexible alkyl spacers. Fibers suitable for obtaining high-quality X-ray patterns of crystalline and smectic phases were produced by stretching samples, in which case the main chains were oriented or, with even better success, by alignment of the polymer side chains in a magnetic field. Ordered domains were detected for the crystalline and smectic state which were differently oriented depending on the fiber producing procedure. However, the packing of the chains within the domains is unaffected by the alignment procedure. The packing of the crystalline phase differs little from commonly known polymeric systems, and the smectic phase can be described with the same kind of packing in a less ordered state.