Thin film holographic gratings have attracted significant attention due the tailorability of their photonic properties. The ability of holography to create materials with unique photonic properties is particularly promising when combined with stimuli-responsive liquid crystals. Holographic polymer-dispersed liquid crystals (H-PDLCs) are an example of such a system where nonuniform irradiation is used to template alternating polymer-rich and polymer-poor regions with a periodicity related to the illumination wavelength. These systems typically use nonmesogenic monomers at a concentration range where a significant volume fraction of the final system is polymer. Here, we present a reconfigurable material that was generated by holographically polymer stabilizing liquid crystals (H-PSLCs) using liquid crystalline monomers, thereby enabling both alternating regions to be liquid crystalline. The “stabilizing effect” of the liquid crystalline polymer leads to a material with regions of periodic transition temperatures. As written, the polymer-rich regions have a higher isotropic transition temperature than the polymer-poor regions. Upon heating these samples beyond the isotropic temperature of the polymer-poor regions, a vivid wavelength specific reflection appears due to the refractive index mismatch between the ordered liquid crystalline polymer-rich regions and the disordered isotropic polymer-poor regions. When these materials are further heated to the isotropic temperature of the polymer-rich regions, the samples again return to a transparent state because the refractive index modulation between the alternating isotropic regions is negligible. By tailoring the liquid crystalline isotropic transition temperature to be near-room temperature, modest AC-fields can be used as an Ohmic heat source to drive the thermal color change.

中文翻译：

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全息图案化液晶凝胶中的可重构反射色

薄膜全息光栅由于其光子特性的可定制性而引起了极大的关注。与刺激响应性液晶结合使用时，全息技术产生具有独特光子特性的材料的能力特别有前途。全息聚合物分散液晶（H-PDLC）是这种系统的一个示例，其中使用非均匀照射来以周期与照明波长相关的周期来交替交替填充富含聚合物和缺乏聚合物的区域。这些系统通常在最终系统的显着体积分数为聚合物的浓度范围内使用非介晶单体。在这里，我们介绍了一种可重构材料，该材料是使用液晶单体通过全息聚合物稳定液晶（H-PSLC）生成的，从而使两个交替区域都是液晶的。液晶聚合物的“稳定作用”导致材料具有周期性转变温度的区域。如所写，富聚合物区域具有比贫聚合物区域更高的各向同性转变温度。在将这些样品加热到聚合物贫乏区域的各向同性温度之上之后，由于有序液晶聚合物富裕区域与无序各向同性聚合物贫乏区域之间的折射率失配，出现了生动的波长比反射。当将这些材料进一步加热到富含聚合物的区域的各向同性温度时，由于交替的各向同性区域之间的折射率调制可忽略不计，因此样品再次返回到透明状态。