J. Weilepp et Hr. Brand, DIRECTOR REORIENTATION IN NEMATIC-LIQUID-SINGLE-CRYSTAL ELASTOMERS BYEXTERNAL MECHANICAL-STRESS, Europhysics letters, 34(7), 1996, pp. 495-500
As has been shown recently by Kundler and Finkelmann, a sample of nema
tic-liquid-single-crystal elastomers subject to a mechanical stress pe
rpendicular to the initial director orientation shows a reorientation
of the director reminiscent of that observed in low-molecular-weight n
ematic Liquid crystals in a magnetic held. Here we present a simple mo
del, which captures all the essential features. We calculate the thres
hold stress and show that the director reorientation occurs over the e
ntire sample. A weakly nonlinear analysis gives a forward bifurcation
in agreement with the experimental results. We also discuss the origin
of the domain walls in the director observed experimentally and give
an expression for the thickness of these walls.