Photonic Crystals via 3D Printing of Block Co-polymers

光子晶体是周期性的纳米结构材料，可以反射特定波长的光，从而实现对光的控制和操纵。例如，自然界中可以找到的结构颜色包括蛋白石、孔雀和蝴蝶。人造光子晶体被用作光导或反射器，并具有实现高速光学计算的潜力。到目前为止，光子晶体的制造要么昂贵，要么在几何形状上受到限制。三维(3D)打印光子晶体材料的能力将使能够通过经济和多功能平台控制光流动的复杂物体的生产成为可能，并将加速它们在各种应用中的部署。该奖项支持通过3D打印组装成光子晶体的嵌段共聚物的合成方面的基础研究。这项工作的更广泛影响将建立3D打印光子晶体的技术，并使可持续结构颜色、太阳能收集和城市热岛缓解等应用成为可能。这项工作将通过在实验室和课堂环境中接触这些主题，在STEM的几个学科中培养下一代科学家，包括工程学、材料和聚合物科学以及3D打印。由于自下而上的自组装和使用商品塑料的潜力，将嵌段共聚物组装成光子晶体在经济上是有吸引力的。然而，组装到具有足够大的磁区尺寸的纳米结构材料以在可见光谱中产生光子带隙是具有挑战性的。在很大程度上，这一挑战源于聚合物链纠缠的基本性质，它为自组装引入了一个能量势垒。研究团队将专注于设计嵌段共聚物，以降低这种能量障碍，并增强3D打印时间尺度上的组装能力。通过这些研究获得的基础知识将应用于3D打印光学光导。

Photonic crystals are periodic nanostructured materials that reflect specific wavelengths of light allowing for control and manipulation of light. Structural colors that can be found in nature include opals, peacocks and butterflies, for example. Artificial photonic crystals are used as light guides or reflectors and possess the potential to enable high speed optical computing. To date, the fabrication of photonic crystals is expensive or limited in geometric shape. The ability to three dimensionally (3D) print photonic crystal materials will enable the production of complex objects capable of controlling the flow of light via an economical and versatile platform and will accelerate their deployment for a variety of applications. This award supports fundamental research in the synthesis of block copolymers that assemble to photonic crystals through 3D printing. The Broader Impacts of this work will establish the technology to 3D print photonic crystals and enable application such as sustainable structural color, solar energy harvesting, and urban heat island mitigation. This work will serve to educate next-generation scientists in STEM across several disciplines, including engineering, materials and polymer science, and 3D printing, through exposure to these topics in laboratory and classroom environments. The assembly of block copolymers to photonic crystals is economically attractive due to bottom-up self-assembly and the potential to use commodity plastics. However, the assembly to nanostructured materials with domain sizes large enough to give rise to photonic bandgaps in the visible spectrum is challenging. In large part, this challenge arises from the fundamental property of polymer chain entanglement, which introduces an energy barrier to self-assembly. The research team will focus on designing block copolymers that reduce this energy barrier and have enhanced capability for assembly on the timescale of 3D printing. The fundamental knowledge gained through these studies will be applied toward 3D printing optical light guides.