Individually Dispersed Wood-Based Cellulose Nanocrystals

Good dispersion of cellulose nanocrystals (CNCs) in the polymer matrix is one of the key factors to obtaining good properties in the resulting nanocomposites. However, the preparation of individually dispersed CNCs in solvents or in polymer matrices has been a challenge. In this study, individually dispersed wood-based CNCs have been successfully prepared in solvents, including dimethylformamide (DMF), H₂O, and a mixture of H₂O/DMF, by sonication of moisture-containing CNCs. The CNCs dispersions were characterized by dynamic light scattering (DLS). It is found that CNCs containing above about 3.8 wt % moisture is critical for achieving individually dispersed CNC in solvents. Hydrodynamic radius (R_h) of CNCs is smaller in H₂O/DMF co-solvent mixture than that in pure DMF or in pure H₂O under same sonication treatment conditions. Experimental results have been corroborated using molecular simulation study.