Semisoft elasticity and director reorientation in stretched sheets of nematic elastomers.

Electrically driven director-rotation of swollen nematic elastomers as revealed by polarized Fourier transform infrared spectroscopy.

We have investigated the director reorientation behavior of unconstrained nematic gels (nematic elastomer swollen by low molecular mass liquid crystals) under electric fields by means of polarized Fourier transform infrared (FTIR) spectroscopy. The polarized FTIR reveals that the director rotates about the (y) axis normal to the original director ( x axis) and field directions ( z axis), and th...

Nematic fluctuations and semisoft elasticity in liquid-crystal elastomers.

We give a detailed theory of nematic fluctuations in liquid-crystal elastomers (LCEs) and calculate relaxation rates as obtained by dynamic light scattering (DLS). In ideal LCEs, a nematic state is formed by a spontaneous orientational symmetry breaking of an isotropic state, manifesting itself in an existence of a coupled director-shear soft mode (Goldstone mode). The relaxation rate of the so...

Elastic Instability and Stripe Domains in Liquid Crystalline Elastomers

We consider the elastic and orientational response of a uniform nematic elastomer subjected to an extension perpendicular to its director. By allowing a possibility of local shear in the material, we show that the effect of "soft elasticity" leads to a new regime of director reorientation, through a highly non-uniform stripe domain state (in contrast to earlier predictions and observations of a...

Soft Elastic Response of Stretched Sheets of Nematic Elastomers: a Numerical Study

Semisoft nematic elastomers and nematics in crossed electric and magnetic fields.

Nematic elastomers with a locked-in anisotropy direction exhibit semisoft elastic response characterized by a plateau in the stress-strain curve in which stress does not change with strain. We calculate the global phase diagram for a minimal model, which is equivalent to one describing a nematic in crossed electric and magnetic fields, and show that semisoft behavior is associated with a broken...