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

The morphological features of side-on fixed liquid crystalline polymer s in an oriented state are investigated using polarizing microscopy, s mall angle light scattering (SALS) and infra-red dichroism techniques. A conventional side-chain polymer with mesogenic units attached longi tudinally to the backbone is also studied for comparison. Banded textu re usually only reported for main-chain liquid crystalline polymers is observed for these side-on fixed polymers under the crossed polarizin g microscope, and SALS measurements also show typical grating diffract ion patterns. This implies that side-on fixed rigid mesogens may signi ficantly affect the conformation of the main chain of molecules, and t he molecule as a whole may become rather rigid, exhibiting behaviour s imilar to that of the main chain. Infra-red dichroism measurements ind icate that the main-chain axes of the molecules tend to orient in dire ctions close to the shear direction. The side-on fixed mesogens are pa cked around the backbone, but their axes are not parallel to the latte r.