Biodegradable and Insoluble Cellulose Photonic Crystals and Metasurfaces
Vincenzo Caligiuri, Giacomo Tedeschi, Milan Palei, Mario Miscuglio, Beatriz Martín‐García, Susana Guzmán‐Puyol, Mehdi Keshavarz Hedayati, Anders Kristensen, Athanassia Athanassiou, R. Cingolani, Volker J. Sorger, Marco Salerno, Francesco Bonaccorso, Roman Krahne, José A. Heredia‐Guerrero
Abstract
replica molding using pure cellulose and a blended version with nonedible agro-wastes. Both materials are biodegradable in soil and seawater according to the ISO 17556 standard. The pure cellulose films are transparent in the vis-NIR spectrum, having a refractive index similar to glass. The microstructured photonic crystals show high-quality diffractive properties that are maintained under extended exposure to water. Nanostructuring the cellulose transforms it to a biodegradable metasurface manifesting bright structural colors. A subsequent deposition of Ag endowed the metasurface with plasmonic properties used to produce plasmonic colors and for surface-enhanced Raman scattering.