Development of redispersible cellulose nanofibers through surface treatment using polyethylene oxide

The irreversible agglomeration of wet cellulose nanofibers (CNF) during dehydration, storage, and transportation is a well-recognized challenge in practical application. The present work reports a novel method for obtaining water-redispersible dried CNF by performing surface treatment with poly (ethylene oxide) (PEO) during the freeze-drying process. The CNF used in the experiments were prepared in-house by combining radiation degradation, mechanochemical treatment, and high-pressure homogenization. Various techniques including AFM, XPS, Rheometer, XRD, UV-vis spectrophotometer, FT-IR, Congo red adsorption method, Particle size and ζ-potential analysis were systematically employed to elucidate the structural and interfacial modifications induced by PEO. The results indicate that PEO introduces steric hindrance and fosters intermolecular interactions, which transiently inhibit hydrogen-bond formation during dehydration while allowing re-dispersion through bond reconfiguration upon rehydration. A critical point of PEO content at about 0.10 wt% was identified. Below this value, incomplete surface coverage resulted in inefficient weakening the interaction between CNF. While when the PEO content was high than the point, bridge flocculation became dominant, causing the CNF dispersion to aggregate. This simple and environmentally friendly strategy demonstrates significant potential for facilitating broader practical use of CNF-based materials across various technological fields.