Modeling Defects, Shape Evolution, and Programmed Auto-origami in Liquid Crystal Elastomers
| Autor: | Andrew Konya, Robin L. B. Selinger, Vianney Gimenez-Pinto |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Polymers finite element simulation Materials Science (miscellaneous) Bent molecular geometry FOS: Physical sciences Geometry 02 engineering and technology Bending Condensed Matter - Soft Condensed Matter 010402 general chemistry 01 natural sciences lcsh:Technology Topological defect symbols.namesake Liquid crystal Gaussian curvature Image warping Materials nonlinear elasticity lcsh:T shape-programmable materials non-linear elasticity 021001 nanoscience & nanotechnology Symmetry (physics) 0104 chemical sciences Liquid Crystals Transverse plane symbols Soft Condensed Matter (cond-mat.soft) 0210 nano-technology |
| Zdroj: | Frontiers in Materials, Vol 3 (2016) |
| ISSN: | 2296-8016 |
| Popis: | Liquid crystal elastomers represent a novel class of programmable shape-transforming materials whose shape change trajectory is encoded in the material's nematic director field. Using three-dimensional nonlinear finite element elastodynamics simulation, we model a variety of different actuation geometries and device designs: thin films containing topological defects, patterns that induce formation of folds and twists, and a bas-relief structure. The inclusion of finite bending energy in the simulation model reveals features of actuation trajectory that may be absent when bending energy is neglected. We examine geometries with a director pattern uniform through the film thickness encoding multiple regions of positive Gaussian curvature. Simulations indicate that heating such a system uniformly produces a disordered state with curved regions emerging randomly in both directions due to the film's up-down symmetry. By contrast, applying a thermal gradient by heating the material first on one side breaks up-down symmetry and results in a deterministic trajectory producing a more ordered final shape. We demonstrate that a folding zone design containing cut-out areas accommodates transverse displacements without warping or buckling; and demonstrate that bas-relief and more complex bent-twisted structures can be assembled by combining simple design motifs. 11 pages, 7 figures |
| Databáze: | OpenAIRE |
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