Biaxially stretched nematic liquid crystalline elastomers

• Published in: The European physical journal. E, Soft matter and biological physics Vol. 35; no. 1; p. 2
• Main Authors: Diaz-Calleja, R., Riande, E.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2012; EDP Sciences
• Subjects: Algorithms; Anisotropy; Applied sciences; Biological and Medical Physics; Biophysics; Complex Fluids and Microfluidics; Complex Systems; Elasticity; Elastomers - chemistry; Exact sciences and technology; Liquid Crystals - chemistry; Mechanical properties; Models, Chemical; Nanotechnology; Organic polymers; Physicochemistry of polymers; Physics; Physics and Astronomy; Polymer Sciences; Properties and characterization; Regular Article; Shear Strength; Soft and Granular Matter; Stress, Mechanical; Surfaces and Interfaces; Thin Films; Pitchfork Bifurcation; Deformation Gradient; Nematic Liquid Crystal; Trace Formula; Stripe Domain; Side chain; Liquid crystal polymers; Elastomer; Crosslinked polymer; Theoretical study; Laminated structure; Biaxial drawing; Nematic crystals; Modeling
• ISSN: 1292-8941; 1292-895X
• DOI: 10.1140/epje/i2012-12002-5

The biaxial stretching of sheets of liquid crystalline neo-Hookean elastomer has been studied in the isotropic case. The results suggest two types of laminate structures in the process of quasiconvexification of the free energy, a fact that implies the appearance of several shear terms in the deformation gradient matrix. More that one decomposition of the deformation gradient is possible, which is consistent with a bifurcation in the undeformed configuration (
= 1) . This situation is similar to the well-known Rivlin’s problem of the triaxial symmetric traction of a neo-Hookean cube. The problem can easily be generalized for an anisotropic material by introducing a semisoft term in the free-energy expression. In this case, the horizontal plateau corresponding to the minimal energy, characteristic of the soft elasticity, disappears, and only an equilibrium condition is obtained.