Effects of mechanical constraint on director configuration of monodomain nematic elastomers under temperature variation

Abstract

Director configuration of a side-chain type 'monodomain' nematic elastomer with global director under temperature variation is investigated in a mechanically constrained geometry where the thermally induced macroscopic deformation is strictly prohibited. The corresponding elastomer in the unconstrained geometry exhibits a finite elongation along the director by cooling to a temperature in the nematic state from the isotropic state as a result of an increase in nematic order. The mechanical constraint, where the macroscopic dimensions in the nematic state are kept to be the same as those in the isotropic state, has a pronounced effect on director configuration: The constrained elastomer shows a 'polydomain' texture composed of randomly oriented local domains in the nematic state.