High-yield production of lignin nanoparticle photonic glasses.

Lignin has emerged as a sustainable alternative to fossil-based polymers in advanced materials such as photonics. However, current methods for preparing photonic lignin materials are limited by non-benign organic solvents and low production yields. In this work, we present a highly efficient process that enables the production of photonic glasses with yields ranging from 48% to 72%, depending on the size of the lignin nanoparticles obtained from herbaceous soda lignin, softwood kraft lignin, and hardwood organosolv lignin. The hydrodynamic diameter of lignin nanoparticles can be regulated by the rate of water addition to the lignin-ethanol solution. We demonstrate that this control over particle size allows for tailoring the color of the photonic glass across the visible spectrum.