Textured deformations in liquid crystal elastomers

Abstract

Liquid crystal elastomers exhibit very rich elastic behaviour because they couple elastic fields and mobile liquid crystal order. One striking phenomenon is the formation of textured deformations: a homogenous elastomer sometimes responds to a macroscopically homogenous imposed strain by forming a spatially fine mixture of very different deformations (a texture) that average to the imposed strain. This occurs because some large strains can be accommodated by rotation of the liquid crystal order, so they cost little energy to impose, while other equally large (or smaller) strains cannot and hence are energetically expensive. If one of these latter strains is imposed macroscopically, the elastomer's energy is lowered if it can form a fine mixture of larger but lower energy strains that average to the imposed deformation. Great progress has been made in understanding this behaviour over the last 10 years. Here, we review the key theoretical ideas and highlight several predicted textures which merit experimental attention. This review assumes little prior knowledge of elasticity or liquid crystal elastomers so hopefully it will be accessible to both non-elasticians and elasticians from other fields, notably the study of martensite which is a highly analogous system but with small strains and discrete broken symmetries rather than large strains and continuous broken symmetries.

Keywords:

• liquid crystal
• elastomer
• texture deformation
• elasticity