Polarities-Induced Weakening of Molecular Interaction and Formation of Nanocellulose with Different Dimensions

Additives with different polarities were used in the fabrication of nanocellulose by ball-milling. It was found that the dimension of cellulose nanomaterials could be controlled by the additive polarity. Because there are hydrophilic and hydrophobic crystal planes, additives with different polarities may permeate into the interface between the crystal planes with different additive hydrophilicities. It was suggested that the polar additive molecules could migrate into the interface between the hydrophilic crystalline faces (110 and 1 (1) over bar0) and weaken the hydrogen bonding interaction during milling, which results in slippage and peeling along the 110 and 1 (1) over bar0 planes and eventually allows one-dimensional cellulose nanofibers. On the other hand, nonpolar and medium-polar additive molecules can only permeate into the interface between the hydrophobic crystalline face (200 plane) and weaken the hydrophobic interaction during milling, which results in the slippage and peeling along 200 planes and the formation of two-dimensional cellulose nanosheets. The results of this study may facilitate the regulated and controllable fabrication of micro-/nanocellulose with different morphologies and dimensions.