Patterning order and disorder with an angle: Modeling single-layer dual-phase nematic elastomer ribbons

Abstract

Liquid crystal polymer networks have demonstrated a rich variety of actuation behavior and stimulus-responsive properties. Actuation in these single-phase materials is given by spatial variations in their liquid crystal director microstructure in balanced coexistence with rubber elasticity. However, experimental studies have shown that complex actuation in elastomeric materials can also be engineered by combining well-defined isotropic regions along with liquid crystalline ordered regions. Via finite element elastodynamics simulations, we investigate the actuation behavior of these dual-phase nematic elastomer ribbons based on several key design factors: director orientation, pattern orientation, as well as domain and sample size. We demonstrate the variety of shapes that these materials can exhibit, including twisting, bending, accordion folding, and hybrid flat-helix states. Overall, our simulations show an exceptional agreement with experimental observations, providing light for the further development of soft stimulus-responsive materials with complex microstructures.