Photonic Marvels: Exploring the Self-Assembly of Cellulose Nanocrystals for Sustainable Materials and Beyond

Cellulose nanocrystals (CNCs) are biodegradable, plant-derived colloidal particles that can self-assemble through evaporation-induced self-assembly (EISA) to form photonic films. The ability of CNCs to organize structurally colored films has garnered significant attention as a promising source of sustainable materials. CNCs serve as versatile photonic building blocks for creating biobased colored materials. This review provides a comprehensive overview of the latest advancements in chiral photonic CNC (CPCNC) materials. We delve into the chiral structures of these materials and factors affecting the EISA route, exploring their fundamental principles and bottom-up synthesis techniques. Additionally, various responsive CPCNCs are systematically introduced with a focus on their mechanisms, properties, and potential applications. The review concludes with a discussion of emerging applications, challenges, and future opportunities for CPCNCs. By leveraging the unique properties of CPCNCs within complex responsive polymer networks, we see significant potential for developing innovative physicochemical sensors, structural coatings, and optical devices.