MORPHOLOGICAL-STUDY OF ORIENTED FILMS OBTAINED FROM SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS

The morphological features of side-on fixed liquid crystalline polymers in an oriented state are investigated using polarizing microscopy, small angle light scattering (SALS) and infra-red dichroism techniques. A conventional side-chain polymer with mesogenic units attached longitudinally to the backbone is also studied for comparison. Banded texture usually only reported for main-chain liquid crystalline polymers is observed for these side-on fixed polymers under the crossed polarizing microscope, and SALS measurements also show typical grating diffraction patterns. This implies that side-on fixed rigid mesogens may significantly affect the conformation of the main chain of molecules, and the molecule as a whole may become rather rigid, exhibiting behaviour similar to that of the main chain. Infra-red dichroism measurements indicate that the main-chain axes of the molecules tend to orient in directions close to the shear direction. The side-on fixed mesogens are packed around the backbone, but their axes are not parallel to the latter.