Molecular engineering of stimuli-responsive, functional, side-chain liquid crystalline copolymers: synthesis, properties and applications

Abstract

This review describes the recent progress made in designing stimuli-responsive, functional, side-chain, end-on mesogen attached liquid crystalline polymers (LCPs). Developments in synthetic methodologies including controlled and living techniques provide an easy access to well-defined liquid crystalline polymers. For example, the synthesis of linear liquid crystalline block copolymers (LCBCPs), block copolymers with a linear, coil–coil, non-LC block and an end-on mesogen attached LC block, provides a route to polymers with morphology and properties akin to conventional block copolymers. However, synthesis of topologically branched LCBCPs with a branched coil–coil non-liquid LC block and an end-on mesogen attached LC block is used to manipulate the phase behavior, morphology and alignment kinetics of the resultant polymer. Furthermore, synthesis of branched liquid crystalline random copolymers wherein the branched coil–coil non LC unit and end-on mesogen LC unit are statistically distributed results in never-before-seen helical and curved interfaces with new and enhanced properties. Finally, synthetic strategies to incorporate organic dye molecules into a variety of liquid crystalline polymer frameworks produce new optically active and adaptive soft materials. In the Outlook section, the need for topologically diverse synthetic and naturally derived liquid crystalline polymer architectures along with processing tools and field directed assemblies to produce functional materials and their applications are discussed.