Polymerisable Liquid-Crystal Systems Beyond Elastomers: Mesophase Control, Alignment, Optical Function and Stability

Polymerisable liquid-crystal systems extend well beyond liquid-crystal elastomers. Reactive mesogens can form rigid or glassy anisotropic networks, polymer-stabilised liquid crystals, optical retarders, chiral photonic structures and patterned microarchitectures. In all of these, the functional state depends on orientational order at the moment it is locked by polymerisation. Cure conversion alone is therefore an incomplete quality metric. This review separates mesophase identity, director alignment, network fixation and optical function; examines thermal, electric-field and photoalignment routes; and defines metrology for birefringence, retardation, texture and spatial registration. Published work demonstrates initiatorless photopolymerisation of liquid-crystal monomers, photopolymerisation in mesogenic solvents, patterned reactive-mesogen architectures and photo-imprinted helical order. [1-4] The qualification framework emphasises that a printed or coated article can be geometrically correct while its director field is wrong, metastable or thermally erased. ER-416.