Rheological behavior of carboxymethylcellulose and cellulose nanocrystal aqueous dispersions

This study investigated the rheological properties of cellulose nanocrystal (CNC) suspensions in carboxymethylcellulose (CMC) polymer solutions by studying steady shear viscosities, linear viscoelastic behaviors, applicability of the Cox–Merz rule, and time-dependent behavior. The rheological measurement showed that interactions between CNC and CMC resulted in liquid crystalline domains and a substantial increase in viscosity, shear-thinning, elasticity, and thixotropy. Depletion flocculation formed a percolated structure of liquid crystalline domains, resulting in a gel-like structure, which was evidenced by polarized optical microscopy. The strong effects on rheological properties by mixing small quantities of CMC and CNC suggest that this system may find applications where tunable rheological properties of aqueous polymeric systems are desirable.