Transparent Insulators with a Tough Nanocellulose Skeleton Formed via Freeze-Drying

-BuOH)-exchanged wet gels with a stiffened network skeleton. The visible-light transmittance values of the cryogels ranged from approximately 80-90%, and the thermal conductivity reached as low as 0.023 W/m·K. We also extended this approach to chitin nanofibers (ChNFs) to demonstrate its universality. The resulting ChNF cryogels exhibited similar high transparency (∼80%) and low conductivities (0.022 W/m·K). These cryogels, with the potential for scalable production, are suitable as interspace materials for use in double-glazed windows, offering a promising solution for sustainable transparent insulators in energy-efficient building and vehicle applications.