Soft elasticity is not necessary for striping in nematic elastomers

The neoclassical model for nematic elastomers, which displays soft elasticity, predicts striping in stretched sheets. Thus the experimental observation of striped domains has been suggested as evidence for soft elasticity. Here we show that the postulated director rotations and shears in the domain regions are also predicted by more general constitutive models that do not involve any notion of softness. Striping in nematic elastomers may therefore be a more general phenomenon that is not necessarily an indication of soft elasticity. Furthermore, constitutive models more general than the neoclassical model may also explain the behavior of some nematic elastomers that do not appear to exhibit striping. (c) 2006 American Institute of Physics.