Preparation and properties of chitosan-nanodiamond dispersions and composite films

Nanocomposite-forming solutions of chitosan in acetic acid (CS center dot HOAc) or hydrochloric acid (CS center dot HCl) and containing nanodiamonds (NDs) were produced without ultrasound treatment, and CS center dot HCl-ND and CS center dot HOAc-ND nanocomposite films were prepared by solution casting. The NDs were uniformly distributed in the polymer matrix by stabilization of the dispersion with use of dilute CS center dot HOAc or CS center dot HCl solutions before mixing with the concentrated chitosan solutions. CS center dot HCl-ND and CS center dot HOAc-ND composite films were then prepared and characterized by the measurement of mechanical properties and by atomic force microscopy methods (topography, phase-contrast, and Kelvin probe force microscopy imaging). The differences in the structures and properties of the films produced on CS center dot HOAc and CS center dot HCl are discussed. A stronger interaction was found between phases in the CS center dot HCl-ND films than in the CS center dot HOAc-ND films.