Hairpin rubber elasticity
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK
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Published online: 31 January 2005
We model the elastic properties of main chain liquid crystalline elastomers, formed by cross linking chains in a strongly nematic state, when they have hairpin defects. We study the response of the elastomer to imposed uniaxial extension along the nematic direction, and employ a microscopic model of how the deformation is distributed non-affinely amongst the hairpin and straight chain populations. The rubber shows a plateau in the stress as a function of the elongation imposed along the director. It is a consequence of the depletion of the actively stretching population of hairpin chains and should not be confused with soft elasticity effects associated with director rotation.
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag, 2005