Paraffin particle dispersion costabilized by W-doped VO2 nanoparticles and chitosan for the fabrication of functional nanocellulose film

The development of functional window films for energy savings and privacy protection has attracted consider-able attention. Herein, a functional nanocellulose film was fabricated via a papermaking technique by using the naturally formed network structure of nanocellulose film to obtain privacy protection and to encapsulate paraffin particles stabilized by W-doped VO2 nanoparticles and chitosan. The paraffin particles stabilized by W-doped VO2 nanoparticles and chitosan were prepared via an emulsion approach without using surfactant. The incor-poration of paraffin into the nanocellulose film not only enhances the latent heat and lowers the forward transmittance of the nanocellulose film but also improves its hydrophobicity. The presence of a small amount of W-doped VO2 nanoparticles in the paraffin particle dispersion further increases the forward transmittance and latent heat of the nanocellulose film, especially at elevated temperatures. Meanwhile, the introduction of chitosan in the paraffin particle dispersion significantly improves the toughness of the nanocellulose film. Consequently, the incorporation of paraffin particles endows the nanocellulose film with hydrophobicity and toughness as well as good privacy protection and thermal insulation for energy savings at both room and elevated temperatures, making the as-prepared nanocellulose film a promising functional window film.