title: Hairpin rubber elasticity.
abstract: 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.
authors.affiliation: Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK. jma39@hermes.cam.ac.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Adams
authors.forename: M
authors.initials: M
authors.lastname: Warner
mesh_terms: D003198:Computer Simulation; D004548:Elasticity; D020724:Elastomers / Q000032:analysis / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D011108:Polymers / Q000032:analysis / Q000737:chemistry; D013314:Stress, Mechanical
chemical_list: D020724:Elastomers; D011108:Polymers