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Slow stress relaxation in randomly disordered nematic elastomers and gels

S. M. Clarke·E. M. Terentjev
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Abstract

Randomly disordered (polydomain) liquid crystalline elastomers align under stress. We study the dynamics of stress relaxation before, during and after the Polydomain-Monodomain transition. The results for different materials show the universal ultra-slow logarithmic behaviour, especially pronounced in the region of the transition. The data is approximated very well by an equation Sigma(t) ~ Sigma_{eq} + A/(1+ Alpha Log[t]). We propose a theoretical model based on the concept of cooperative mechanical resistance for the re-orientation of each domain, attempting to follow the soft-deformation pathway. The exact model solution can be approximated by compact analytical expressions valid at short and at long times of relaxation, with two model parameters determined from the data.

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S. M. Clarke, E. M. Terentjev. 1998-05-28. Slow stress relaxation in randomly disordered nematic elastomers and gels. https://doi.org/10.1103/physrevlett.81.4436

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