J. Phys. II France
Volume 7, Numéro 8, August 1997
Page(s) 1059 - 1069
DOI: 10.1051/jp2:1997171
J. Phys. II France 7 (1997) 1059-1069

Critical Stripe-Domain Instability of Nematic Elastomers

H. Finkelmann1, I. Kundler1, E.M. Terentjev2 and M. Warner2

1  Institut für Makromolekulare Chemie, Universität Freiburg, 79104 Freiburg, Germany
2  Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, U.K.

(Received 11 March 1997, revised 23 April 1997, accepted 6 May 1997)

We present an experimental and theoretical investigation of the critical formation of stripe domains in monodomain nematic elastomers. Domains with alternating sense of director rotation are formed when the material is stretched perpendicular to the initial director alignment. A wide range of differing samples are shown to have a singular onset to director rotation at a threshold deformation and a second singular point at the end of the stripe domain region. All the data collapses onto a master plot revealing a universal behaviour. We analyse theoretically the threshold properties of the stripe phase. The analysis of free energy yields a first order transition into a fully-coarsened texture without any intermediate state of sinusoidal modulation.

© Les Editions de Physique 1997