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.
