Construction of chitosan/ZnO nanocomposite film by in situ precipitation

In the present work, flexible chitosan/ZnO nanocomposite films were prepared by a green and facile method through in situ precipitation of nano-ZnO (nZnO) in the chitosan film. Zn(Ac)₂ was added in chitosan solution to provide Zn²⁺, thus Zn²⁺ was fixed in the chitosan matrix and converted into nZnO through interaction with NaOH with heating. The structure and properties of the hybrid films were characterized by Field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Fourier transform infra-red (FT-IR), X-ray diffraction (XRD) and tensile testing. The results indicated that there was strong coordination interaction existed between Zn²⁺ and chitosan matrix for the good dispersion of nZnO in the chitosan film. Furthermore, nZnO distributed evenly in the chitosan and aggregated to form micro-nano-binary hierarchical structure, mimicking lotus leaf structure. Therefore, this work provides an effective way to prepare biocompatible and antibacterial chitosan/ZnO nanocomposite films, showing potential applications in the fields of antibacterial packaging and dressings.