2024-12-17 ハーバード大学
＜関連情報＞
- https://seas.harvard.edu/news/2024/12/shape-changing-soft-material-soft-robotics-smart-textiles-and-more
- https://www.science.org/doi/10.1126/science.adq6434
多段階双方向変形可能な液晶エラストマーをプログラミング Programming liquid crystal elastomers for multistep ambidirectional deformability
Yuxing Yao, Atalaya Milan Wilborn, Baptiste Lemaire, Foteini Trigka, […], and Joanna Aizenberg
Science Published:5 Dec 2024
DOI:https://doi.org/10.1126/science.adq6434
Editor’s summary
Designing structures capable of multiple deformations in response to a single stimulus requires some combination of hybrid material constructs, complex and precise geometric architectures, and multiple stimuli. Although liquid crystal elastomers (LCEs) can undergo large shape changes when driven through their isotropic-nematic transition, the change is typically unidirectional. Yao et al. designed and synthesized LCEs using two monomers that individually only show nematic-to-isotropic transitions. However, when combined, they display two liquid crystal phase transitions: isotropic to smectic A and smectic A to smectic C, thus allowing for ambidirectional deformability driven only by changes in temperature. As a result, two shape changes can be observed at the two transitions. —Marc S. Lavine
Abstract
Ambidirectionality, which is the ability of structural elements to move beyond a reference state in two opposite directions, is common in nature. However, conventional soft materials are typically limited to a single, unidirectional deformation unless complex hybrid constructs are used. We exploited the combination of mesogen self-assembly, polymer chain elasticity, and polymerization-induced stress to design liquid crystalline elastomers that exhibit two mesophases: chevron smectic C (cSmC) and smectic A (SmA). Inducing the cSmC-SmA–isotropic phase transition led to an unusual inversion of the strain field in the microstructure, resulting in opposite deformation modes (e.g., consecutive shrinkage or expansion and right-handed or left-handed twisting and tilting in opposite directions) and high-frequency nonmonotonic oscillations. This ambidirectional movement is scalable and can be used to generate Gaussian transformations at the macroscale.
