Eur. Phys. J. E (2009) 30: 371-377
https://doi.org/10.1140/epje/i2009-10535-2

Regular Article

Response of prestretched nematic elastomers to external fields

¹ Theoretische Physik III, Universität Bayreuth, 95440, Bayreuth, Germany
² Max Planck Institute for Polymer Research, P.O. Box 3148, 55021, Mainz, Germany

^* e-mail: andreas.menzel@uni-bayreuth.de
^** e-mail: pleiner@mpip-mainz.mpg.de
^*** e-mail: brand@uni-bayreuth.de

Received: 21 July 2009
Revised: 20 October 2009
Accepted: 23 October 2009
Published online: 5 December 2009

Abstract

We investigate the response of prestretched nematic side-chain liquid single-crystal elastomers to superimposed external shear, electric, and magnetic fields of small amplitude. The prestretching direction is oriented perpendicular to the initial nematic director orientation, which enforces director reorientation. Furthermore, the shear plane contains the direction of prestretch. In this case, we obtain a strongly decreased effective shear modulus in the vicinity of the onset and the completion of the enforced director rotation. For the same regions, we find that it becomes comparatively easy to reorient the director by external electric and magnetic fields. These results were derived using conventional elasticity theory and its coupling to relative director-network rotations.