Shear Flow Rheology of Liquid Crystalline Polymers

The rheological behavior of liquid crystalline polymers in shear flows is reviewed with the aim of pointing out the most important features which characterize tumbling. The latter expression refers to the fact that, in some nematics, the director (i.e., the average molecular orientation) is not stable in shear flows unless some other stabilizing field prevails. Many liquid crystalline polymers seem to be tumbling nematics, so that the molecular orientation achieved in a shear flow may be difficultto control.