Protonation and dip-coating synergistically enhancing dimensional stability of multifunctional cellulose-based films

Cellulose-derived films have received increased attention for replacing petrochemical substrates in various high-tech applications. However, many cellulose composite films are usually limited in practical application due to the strong hydrophilic character. Herein, we fabricated multifunctional waterproof cellulose films via a combination of protonation and dip-coating modifications. This novel cellulose film with 30 wt% poly(methyl methacrylate) (PMMA) possessed excellent superhydrophobicity (static contact angle about 158°), optical transmittance (84%), and haze (91%). Besides, the film simultaneously exhibited remarkable dimensional stability, such as low water swelling (21.79%), water uptake (25.12%), and improved wet tensile strength (~ 50 MPa). After the corrosion test of acidic and basic solutions, moisture resistance at 90% relative humidity for 120 h, and 120 cycles of bending tests, the composite films still showed superior superhydrophobicity, suggesting excellent durability for the composite films. Such multifunctional cellulose films may have potential applications for solar cell panels, antifogging goggles, food packaging, and other waterproof electronic devices.