Synergistic effect of glycerol and ionic strength on the rheological behavior of cellulose nanocrystals suspension system.

To broaden the application of cellulose nanocrystals (CNCs) in the field of biopolymer nanocomposites, a systematic assessment of the viscoelastic properties of CNC suspensions in the presence of glycerol (Gly) and/or sodium chloride (NaCl) was conducted. The viscosity, storage modulus (G'), and loss modulus (G'') increased with increasing concentrations of CNCs and Gly, respectively. Dramatically, the G' and G'' values were raised and tanδ (<1) decreased with the increasing addition of NaCl, indicating that the elastic properties of CNCs in NaCl solutions continuously strengthened, thereby the gel-like response of the network was enhanced. Moreover, the addition of 40% Gly significantly increased the values of G' and G'' for CNCs in NaCl solutions. This work demonstrates new findings related to the rheological properties of CNC gels with Gly/NaCl, and accounts for the interaction mechanisms between CNCs and CNCs/Gly/NaCl, with electrostatic interactions, hydrogen bonds, van der Waals forces, and Na bridging. We wish our study could better serve for future works based on design of CNCs in biomedical and packaging materials industries.