Chitosan particles modulate the properties of cellulose nanocrystals through interparticle interactions: Effect of concentration

The physical and chemical properties of cellulose nanocrystals (CNC) were regulated by physical crosslinking with chitosan particles (CSp). At a fixed concentration (0.5 wt%) of CNC, varying CSp concentration (0.02–0.5 wt%) influenced the morphologies and chemical properties of the obtained complex particles (CNC-CSp). The results of Fourier transform infrared spectroscopy (FTIR) and zeta potential confirmed the electrostatic and hydrogen bonding interactions between CSp and CNC. At a low CSp concentration (0.02–0.05 wt%), the charge shielding effect induced the formation of particle aggregation networks, thus showing increased viscosity, turbidity and size (153.4–2605.7 nm). At a higher CSp concentration (0.1–0.5 wt%), the hydrogen bonding interaction promoted CSp adsorption onto the surface of CNC, thus facilitating the dispersion of CNC-CSp due to electrostatic repulsion caused by surface-adsorbed CSp. In addition, CSp improved the thermal stability , hydrophobicity (41.87–60.02°) and rheological properties of CNC. Compared with CNC, CNC-CSp displayed a better emulsifying ability and emulsion stability, in which CSp could play a dual role (i.e., charge regulator and stabilizer). This study suggests that introducing CSp can improve the properties and application potentials of CNC as food colloids . • Cellulose nanocrystals (CNC) and chitosan (CS) complex particles were prepared. • Interparticle interactions included electrostatic interaction and hydrogen bonding. • CS particles (CSp) can regulate properties of CNC depending on CSp concentration. • CSp improved the hydrophobic, thermal stability and rheological properties of CNC. • Complex particles showed a better emulsifying capacity and emulsion stability.