Highly transparent, hydrophobic, and durable anisotropic cellulose films as electronic screen protectors

Cellulose films have attracted extensive interest in the field of burgeoning electronic devices. However, it remains a challenge to simultaneously address the difficulties including facile methodology, hydrophobicity, optical transparency, and mechanical robustness. Herein, we reported a coating-annealing approach to fabricate highly transparent, hydrophobic, and durable anisotropic cellulose films, where poly(methyl methacrylate)-bpoly(trifluoroethyl methacrylate) (PMMA-b-PTFEMA) as low surface energy chemicals was coated onto regenerated cellulose films via physical (hydrogen bonds) and chemical (transesterification) interactions. The resultant films with nano-protrusions and low surface roughness exhibited high optical transparency (92.3 %, 550 nm) and good hydrophobicity. Moreover, the tensile strength of the hydrophobic films was 198.7 MPa and 124 MPa in dry and wet states, respectively, which also showed excellent stability and durability under various conditions, such as hot water, chemicals, liquid foods, tape peeling, finger pressing, sandpaper abrasion, ultrasonic treatment, and water jet. This work provided a promising large-scale production strategy for the preparation of transparent and hydrophobic cellulose-based films for electronic device protection as well as other emerging flexible electronics.

Automated summary

In this study, a coating-annealing approach was utilized to fabricate highly transparent, hydrophobic, and durable anisotropic cellulose films. Low surface energy chemicals poly(methyl methacrylate)-b-poly(trifluoroethyl methacrylate) (PMMA-b-PTFEMA) were coated onto regenerated cellulose films through physical and chemical interactions. The resulting films exhibited nano-protrusions, low surface roughness, high optical transparency, good hydrophobicity, and excellent stability and durability under various conditions. This work provides a promising large-scale production strategy for transparent and hydrophobic cellulose-based films for electronic device protection and other emerging flexible electronics.