Chiral Photonic Aerogels: Pressure‐Responsive Hierarchical Chiral Photonic Aerogels (Adv. Mater. 21/2019)

Cellulose nanocrystals (CNCs), renewable materials obtained from biomass, have been used to construct lightweight aerogels materials. In article 1808186, Mark MacLachlan and co-workers demonstrate that these materials have interesting optical properties. In their natural state, the materials appear white due to scattering from their 3D hierarchical structure. Upon compression, the materials transform into a 2D layered structure, turning on their chiral photonic properties. By incorporating an elastomer into the CNCs, the mechanoresponsive materials show reversible cycling between white and iridescent.