STRUCTURAL AND STEREOCHEMICAL ISOMERISM EFFECTS IN THERMOTROPIC LIQUID-CRYSTALLINE POLYMERS

A critical survey is presented of the major contributions so far available on the influence of structural and stereochemical isomerism on the physical properties of thermotropic liquid crystalline polymers. The structure-property correlation in liquid crystalline polymeric materials is still far beyond to be satisfactorily rationalizable in terms of chemical and physical responses, as predictable at molecular level and modulable, from a practical point of view, at the stage of polymer formulation. In this connection it will be pointed out how isomerism effects in the polymer-repeating units can play sometimes a key role. For convenience, structural and stereochemical isomerism features shall be treated separately and the systems divided in «side-chain» and «main-chain» type, in accordance with the relative position of the mesogens within the repeating units. © 1990 Società Italiana di Fisica.