(453c) Vertical Direct Ink Write of Bottlebrush Block Copolymers for Structural Color

Materials with structural color can offer a pigment-free and environmentally sustainable approach to coloration by reflecting light based on nanoscale morphology.¹ While bottlebrush block copolymers (BBCPs) are promising candidates for achieving tunable structural color via self-assembly, integrating them into complex 3D geometries remains challenging due to the delicate balance between self-assembly kinetics and solidification during processing.^2,3 In this study, we present a direct ink writing (DIW) approach for the fabrication of 3D structures with dynamically tunable photonic properties using BBCP-based inks. By tuning process parameters such as nozzle speed and polymer concentration, we can control the evaporation behavior during printing, enabling the kinetic trapping of non-equilibrium nanostructures. These morphologies exhibit structural colors that can be tuned continuously during the process without the need for changing the ink composition. This method provides a new approach for the additive manufacturing of structural colors with potential applications in sensing and anti-counterfeiting.

1. Xuan, Zhiyi, Junyu Li, Qingquan Liu, Fei Yi, Shaowei Wang, and Wei Lu. "Artificial Structural Colors and Applications." *The Innovation* 2, no. 1 (2021): 100081.
2. Jeon, Sanghyun, Yash Laxman Kamble, Haisu Kang, Jiachun Shi, Matthew A. Wade, Bijal B. Patel, Tianyuan Pan, et al. "Direct-Ink-Write Cross-Linkable Bottlebrush Block Copolymers for On-the-Fly Control of Structural Color." *Proceedings of the National Academy of Sciences* 121, no. 9 (February 27, 2024): e2313617121.
3. Patel, Bijal B., Dylan J. Walsh, Do Hoon Kim, Justin Kwok, Byeongdu Lee, Damien Guironnet, and Ying Diao. "Tunable Structural Color of Bottlebrush Block Copolymers through Direct-Write 3D Printing from Solution." *Science Advances* 6, no. 24 (2020): eaaz7202.