Eur. Phys. J. E 5, 295-307

Mechanical and order rigidity of nematic elastomers

G.G. Pereira and M. Warner

Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK

(Received 29 September 2000)

Abstract
We calculate the ratio of moduli for extension parallel and perpendicular to the director of nematic elastomers. Elastomers in practice are not ideal nematics with a jump from a finite to zero-order parameter with increasing temperature. Some classes behave as if under effective external fields. These are really internal in origin and leave the system subcritical (still with jumps) or supercritical. We give expressions for general non-ideality and memory of formation conditions, along with its translation into values of the "fields". For the case of supercritical fields, we find that the modulus ratio deviates more from unity, in accord with experiment, than in the subcritical case.

PACS
61.30.-v - Liquid crystals.
82.70.-y - Disperse systems; complex fluids.
81.40.Jj - Elasticity and anelasticity, stress-strain relations..


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001