Polydopamine nanocoating on cellulose nanofiber film and its multifunctional behaviors

This paper presents a simple and upscalable method for enhancing and imparting multifunctionalities onto cellulose nanofiber (CNF) films through nanocoating with polydopamine (PDA). Leveraging a simple two-step process of dopamine seeding and PDA polymerization in mild alkaline Tris–HCl, a uniform and stable PDA nanocoating was successfully formed on the CNF film surface. The resulting PDA-coated CNF films (PDA–CNF) were then thermally annealed at 160 °C to further enhance their multifunctionality. Our results show that the PDA nanocoating profoundly enhanced the films’ UV-shielding properties, Young’s modulus, dielectric properties, and antioxidant activity. FTIR spectra analysis confirmed successful PDA formation onto the CNF surface, and atomic force microscopy revealed a homogenous distribution of nanometer-sized PDA oligomers (~ 170 nm) on the film surface. Moreover, we demonstrated the use of thermally annealed PDA–CNF film as an ascorbic acid detecting electrode, which showed a linear electrochemical response with high stability and excellent reproducibility. These findings contribute to the expanding knowledge of CNF films and their potential as a promising material for various applications. Graphical abstract: [Figure not available: see fulltext.]