POLYDOMAINS IN LIQUID-CRYSTAL ELASTOMERS

In liquid-crystal elastomers, the simultaneous presence of rubber elas ticity due to the crosslinked backbone chains and of optical birefring ence due to the mesogens in the side chains lead to exceptional physic al properties. An elastic deformation of the network influences the or der of the mesogens and, therefore, the optical properties. A theory b ased on a Landau-de Gennes expansion of the free energy is proposed. I n the opaque polydomain phase, the local orientation is given by a com promise between the external mechanical field and a local anchoring in teraction. As the field is increased, it becomes energetically favorab le for the mesogens to align parallel to the mechanical field, and a t ransition to a transparent monodomain structure occurs. Results for th e average orientation, the stress and the chain conformation are given .