Band textures of liquid crystalline polymers in elongational flows
Résumé
A rheooptical device, where an obstacle generates an elongational flow, was used to study the behavior of an anisotropic (hydroxypropyl)cellulose solution. Good agreement was found between calculated and measured elongational rates. After cessation of flow, a band texture appears if the elongation rate is larger than a critical value. The conditions for the formation of the bands, their optical features, and their spacing are similar to those arising after cessation of shear.