X-ray diffraction by liquid crystalline side-chain polymers

This article presents a survey of the literature on X-ray diffraction by mesomorphic side-chain polymers. The first part shows how the polymorphism of these compounds is usually determined with simple experimental techniques. This part also describes how the same techniques can be used to derive more structural information: (1) the exploitation of the wide angle diffuse ring thanks to an easy procedure allows one to measure the nematic order parameter; and (2) the exploitation of the reflections from the smectic layers allows one to study the backbone localization in the smectic phases. The second part describes the observation of different kinds of short range correlations and localized defects through their contribution to the X-ray diffuse scattering. This more elaborate type of study gives access to the elastic properties and, therefore, a more detailed insight into the physics of polymeric mesophases. Copyright (C) 1996 Elsevier Science Ltd.