Stabilized director buckling patterns in nematic elastomers and their dynamic optical effects
Stabilized director buckling patterns in nematic elastomers and their dynamic optical effects
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DOI：
10.1038/s43246-022-00253-3
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发表时间：
2022-05
影响因子：
7.8
通讯作者：
T. Ohzono;H. Minamikawa;E. Terentjev
中科院分区：
文献类型：
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作者：
T. Ohzono;H. Minamikawa;E. Terentjev
珠光和虹彩是一类光扩散效应，表现出与视角相关的亮度和颜色，是用于通知目的和照明设备的重要材料特性。在这里，我们报告了具有自组织周期性双折射模式的弹性体材料，这些材料表现出这些光学效应，并具有额外的动态和可逆可调性。在向列液晶弹性体中，一堆微米厚的层，每一层都有一个向列指向器，从层法线向不同方向倾斜，在向列液晶弹性体中组装一个基于双折射模式的各向异性扩散器。周期性图案是在单轴热收缩引起的屈曲和初始均匀定向状态的旋转后形成的。二级交联可以稳定图案。当变形或温度升高时，具有视角相关颜色的光扩散分别由于应变诱导对准或双折射热随机化的光学效应减弱而可逆地消退。这种弹性体具有可调谐的自组织双折射模式，可用于可重构光学元件和薄膜、磁带、棒和纤维形式的应变/温度检测。
Pearlescence and iridescence, which are a class of light diffusion effects that exhibit sharp viewing-angle-dependent brightness and colors, are important material properties for notification purposes and lighting devices. Here we report elastomeric materials with self-organized periodic birefringent patterns that exhibit these optical effects, with additional dynamic and reversible tunability. A stack of micron-thick layers, each of which has a nematic director tilted from the layer normal in a different direction, assembles a birefringence-pattern-based anisotropic diffuser in a nematic liquid-crystal elastomer. The periodic pattern is formed after buckling induced by the uniaxial thermal shrinkage, and the associated rotation of an initially uniform director state. The patterns can be stabilized by secondary crosslinking. Upon deformation or increasing the temperature, the light diffusion with viewing-angle-dependent colors reversibly fades owing to the diminishing of optical effects via strain-induced alignment or thermal randomization of birefringence, respectively. Such elastomers with tunable self-organized birefringence patterns can be used for reconfigurable optical elements and strain/temperature detection in the form of films, tapes, rods, and fibers.