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Cellulose nanofibers (CNFs) aerogels with controllable surface wettability were prepared by grafting poly(N,N-dimethylamino-2ethyl methacrylate) (PDMAEMA) polymer brushes via surface-initiated atom-transfer radical polymerization. After grafting PDMAEMA polymer, the surface of the aerogel was hydrophobic. However, in the presence of CO 2 , the surface of the aerogel gradually changes from hydrophobic to hydrophilic. The porous structure and CO 2 -responsiveness of PDMAE-MA brushes within the CNFs aerogels allowed for the on−off switching of the oil−water mixture separation process. These CNFs aerogels were recyclable and displayed attractive separation efficiency for oil−water mixture and surfactant-stabilized emulsions. Furthermore, the switchable surface wettability holds an advantage of avoiding oil-fouling, which will greatly improve its recyclability.

Robust and flexible cellulose sponges were prepared by dual-cross-linking cellulose nanofiber (CNF) with γ-glycidoxypropyltrimethoxysilane (GPTMS) and polydopamine (PDA) and used as carriers of metal nanoparticles (NPs), such as palladium (Pd). In situ growth of Pd NPs on the surface of CNF was achieved in the presence of polydopamine (PDA). The modified sponges were characterized with FT-IR, XRD, EDX, SEM, TEM, and TGA. XRD, EDX, and TEM results revealed that the Pd NPs were homogeneously dispersed on the surface of CNF with a narrow size distribution. The catalysts could be successfully applied to heterogeneous Suzuki and Heck cross-coupling reactions. Leaching of Pd was negligible and the catalysts could be conveniently separated from the products and reused.

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Cellulose dissolution is a worldwide issue in the production industry. Especially, the development of highly efficient and green cellulose solvents has been considered as a key factor to restrict the broad application of different cellulose industries. In this study, different chloride salts, such as LiCl, ZnCl2, CaCl2, and FeCl3, with different water amounts were used as green solvents to investigate the driving force of cellulose dissolution. The superfast and highly efficient cellulose dissolution in ZnCl2·3H2O and FeCl3·6H2O was successfully achieved within 5–20 min, which was confirmed by the results of polarized light microscopy. Moreover, the effect of pH and water amounts of the chloride salts on the cellulose structural change and dissolution ability was investigated for a better understanding of the role of chloride salts during the cellulose dissolution process. Especially, the dissolution mechanism of cellulose in ZnCl2·3H2O and FeCl3·6H2O has been provided compared to other non-derivatizing cellulose solvents.