Abstract
For a polymer to be capable of forming a nematic, liquid crystalline state the molecules must be nearly rigid and rodβlike. There are two main classifications of such liquid crystalline states: lyotropic β generally applied to polymer solutions and implying the formation of a low viscosity state in a critical concentration range. and thermotropic β usually applied to melts where the low viscosity mesophase appears over a limited temperature range.
Lytropic βgenerally applied to polymer solutions and implying the formation of a low viscosity state in a critical concentration range. and thermotropic β usually applied to melts where the low viscosity mesophase appears over a limited temperature range.
For polymers we further find that attaining this low viscosity state depends critically on the previous thermomechanical history of the mesophase and that, by appropriate thermoβmechanical history, it is possible to induce a low viscosity state under conditions where such is not spontaneously formed. This extension of the liquid crystal state may also include polymers whose molecular flexibility is such that they do not naturally form liquid crystals.