Self-Assembled Shape-Memory Fibers of Triblock Liquid-Crystal Polymers
| Autor: | A. R. Tajbakhsh, S. V. Ahir, Eugene M. Terentjev |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Materials science Pattern formation Nanotechnology Polymer Shape-memory alloy Condensed Matter Physics Elastomer Electronic Optical and Magnetic Materials Biomaterials chemistry Liquid crystal Electrochemistry Deformation (engineering) Composite material Elasticity (economics) Material properties |
| Zdroj: | Advanced Functional Materials. 16:556-560 |
| ISSN: | 1616-3028 1616-301X |
| DOI: | 10.1002/adfm.200500692 |
| Popis: | Liquid-crystalline elastomers have demonstrated their unique material properties and potential for applications in a number of areas. They also present challenging problems for fundamental science, ranging from applied mathematics of elastic media with microstructure, to physical effects of shape memory, soft elasticity, and pattern formation, and to new synthetic routes and concepts. One of the most remarkable properties of nematic elastomers formed with the director aligned in a monodomain fashion is uniaxial spontaneous deformation in response to any external factor changing the underlying order parameter. The resulting shape memory is very different from all other shape-memory effects reported in the literature in that it is a fully reversible, equilibrium phenomenon (other shape-memory systems act only in a one-stroke way and require a reset afterwards). It also has astonishingly large amplitude, with deformation exceeding 200–300%, and can be stimulated by temperature change, irradiation by light, and exposure to solvents. An overview of these effects, related materials, and the history of publications is available in the literature. [1] One of the difficulties that still restricts the broad range of application of nematic-elastomer actuators is the problem of forming the network with a particular alignment of the nematic director. The most common method currently in use is the technique of two-step crosslinking, pioneered by Kupfer and Finkelmann. [2] It is based on first forming a partially crosslinked gel network with no specified director orientation, then mechanically stretching it, thus inducing an aligning internal stress, and then fully crosslinking the network to record the imposed orientation. Most of the (highly successful) work on monodomain nematic elastomers in the last decade has been |
| Databáze: | OpenAIRE |
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