Strong, tough and degradable cellulose nanofibers-based composite film by the dual crosslinking of polydopamine and iron ions

It is urgently needed to develop an eco-friendly composite films with excellent mechanical properties for biomedicine, optoelectronics, and water treatment applications. Here, we acquired a strong, tough, and sustainable TEMPO-oxidized cellulose nanofiber (TOCN)-based composite film by the dual crosslinking of poly dopamine (PDA) and iron ions (Fe3+). The ultimate TOCN/PDA/Fe3+ ternary composites exhibited outstanding mechanical properties with a strength of 220 MPa, a strain of 13.26% and a toughness of 17.73 MJ m(-3), increasing by 113%, 149%, and 417% compared to pure TOCN film, respectively. This result was caused by the coordination bonds and covalent bonds. Moreover, the TOCN/PDA/Fe3+ composite film also showed excellent degradability, thermal stability and UV-shielding capability.