Sustainable Multiscale High-Haze Transparent Cellulose Fiber Film via a Biomimetic Approach

Chinese traditional Xuan paper is distinguished for its high strength, high toughness, and high flexibility. Microscopically, this remarkable mechanical property is derived from its uniform nano- and microscale structure. Here, inspired by the multiscale structure design of biomaterials and Xuan paper, we report an ultrastrong and ultraflexible transparent cellulose fiber film with an ultrafine nano- and microscale structure. Through introducing micron-sized cellulose fibers into the cellulose nanofiber network, the multiscale film combines high strength (258 MPa) and toughness (7.90 MJ m–3) and low thermal expansion coefficients as well as high light transmittance (82.7%) and high haze (97.4%) simultaneously in one material. Moreover, the multiscale design endows the film to be restored to intactness after being fully folded and rolled, making it a high-performance and eco-friendly alternative film material for practical application in flexible electronic devices.