Liquid-crystalline order in thermotropic copolymers with flexible spacers of different length

Conformational and orientational characteristics of a series of linear thermotropic copolymers, in which the mesogenic groups are separated from the main chain by spacers of different length, were studied by IR spectroscopy, X-ray diffraction, and calorimetry. It was demonstrated that mixed LC order can takes place in such copolymers. In this case, short polymethylene chains uncoil, whereas the longer chains pack to a more compact shape so that the lengths of monomer fragments become equal without violating the coaxiality of mesogenic fragments.