Facile Anisotropic Deswelling Method for Realizing Large‐Area Cholesteric Liquid Crystal Elastomers with Uniform Structural Color and Broad‐Range Mechanochromic Response
| Autor: | Jan P. F. Lagerwall, Venkata Subba Rao Jampani, Rijeesh Kizhakidathazhath, Cyrine Charni, Yong Geng, Anshul Sharma |
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| Přispěvatelé: | European Commission - EC [sponsor], University of Luxembourg [research center] |
| Rok vydání: | 2019 |
| Předmět: |
Range (particle radiation)
Materials science Cholesteric liquid crystal Physics [G04] [Physical chemical mathematical & earth Sciences] 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Elastomer 01 natural sciences 0104 chemical sciences Electronic Optical and Magnetic Materials Biomaterials Physique [G04] [Physique chimie mathématiques & sciences de la terre] Natural rubber visual_art Electrochemistry visual_art.visual_art_medium Composite material 0210 nano-technology Anisotropy Structural coloration |
| Zdroj: | info:eu-repo/grantAgreement/EC/H2020/648763 Advanced Functional Materials |
| ISSN: | 1616-3028 1616-301X |
| DOI: | 10.1002/adfm.201909537 |
| Popis: | Cholesteric liquid crystal elastomers (CLCEs) are soft and dynamic photonic elements that couple the circularly polarized structural color from the cho- lesteric helix to the viscoelasticity of rubbers: the reflection color is mechani- cally tunable (mechanochromic response) over a broad range. This requires uniform helix orientation, previously realized by long-term centrifugation to ensure anisotropic deswelling, or using sacrificial substrates or external fields. The present paper presents a simple, reproducible, and scalable method to fab- ricate highly elastic, large-area, millimeters thick CLCE sheets with intense uni- form reflection color that is repeatably, rapidly, and continuously tunable across the full visible spectrum by stretching or compressing. A precursor solution is poured onto a substrate and allowed to polymerize into a 3D network during solvent evaporation. Pinning to the substrate prevents in-plane shrinkage, thereby realizing anisotropic deswelling in an unprecedentedly simple manner. Quantitative stress–strain–reflection wavelength characterization reveals behavior in line with theoretical predictions: two linear regimes are identified for strains below and above the helix unwinding threshold, respectively. Up to a doubling of the sample length, the continuous color variation across the full visible spectrum repeatedly follows a volume conserving function of the strain, allowing the CLCE to be used as optical high-resolution strain sensor. |
| Databáze: | OpenAIRE |
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