Structure and morphology of liquid‐crystalline polymers

Liquid‐crystalline phases are characterized by structures intermediate between a three‐dimensionally ordered crystal and a disordered fluid. Polymers with liquid‐crystalline structures can be obtained from specific monomers containing mesogenic groups with a tendency to form liquid‐crystalline phases. These mesogenic groups are either incorporated into the main chain or attached to a chain as side groups. In both cases liquid‐crystalline structures, and also enantiotropic liquid‐crystalline phases, have been reported. Smectic polymers are characterized by layered structures with long‐range order in the direction of the layer normal and two‐dimensional short‐range order within the layers. The nematic polymers are characterized by a preferred direction on a microscopic scale and short‐range positional order of the centers of mass of the mesogenic groups. Thermal and textural properties are similar to the corresponding properties of low molecular weight liquid crystals.