Side-chain jacketing effect and mesogen-jacketed liquid crystalline polymers

Abstract

Side-chain liquid crystalline polymers (LCPs) with the mesogens either terminally or laterally attached to the backbone are usually synthesized based on the concept of “flexible spacer”. The insertion of spacers with reasonable lengths between the backbone and mesogens can effectively decouple dynamics of backbone and mesogen, and thus facilitate ordered packing of side-chains. In contrast to that, the molecular design of mesogen-jacketed liquid crystalline polymers (MJLCPs), which belong to the catalog of laterally attached side-chain LCP, attempts to take the advantage of the coupling of side-chain and backbone. At the chemical structure level, the feature MJLCP is that the relatively bulky side-groups such as calamitic mesogens are linked to the backbone through a very short linkage or even a single carbon-carbon band. This arrangement of side-chains can cause significant “jacketing” effect, forcing the backbone to well extend. In this review, we discuss the “jacketing” effect, the special chain conformations of MJLCP due to the “jacketing” effect, and also the liquid crystalline phase structures of MJLCP. We demonstrate that the shape and dimension of MJLCP can be tuned upon using the “jacketing” effect. Furthermore, MJLCP can be used as rod-like component in block copolymers and also as main-chain part in combined main-chain/side-chain LCPs, which can render interesting hierarchical supramolecular orderings.