Interfacial assembly of ZnO-cellulose nanocomposite films via a solution process: a one-step biomimetic approach and excellent photocatalytic properties

A bioinspired mineralization route to directly prepare ZnO-cellulose nanocomposite (ZCN) films from a cellulose-NaOH/urea/zincate solution was demonstrated in this study. By adding non-acid coagulants, an inclusion complex consisting of NaOH, urea and zincate, which was bound to the cellulose molecules, was broken. As a result, the cellulose aggregates occurred, which simultaneously aided the mineralization of ZnO nanostructures at room temperature. The structure and properties of the ZCN films were characterized using FE-SEM, TEM, XRD, UV-Vis spectra, XPS, TG, tensile testing and photocatalytic activity tests. Through changing different coagulants, the content and mean size of ZnO in the ZCN films varied in the range of 10.8-14.9 wt% and 56.8-146.8 nm, respectively. Owing to good interfacial interaction, the ZCN films displayed good mechanical and excellent photocatalytic properties. The mechanical strength and elongation at break of the ZCN films attained 46.7 MPa and 6.4 %, respectively. The degradation efficiency of rhodamine B reached 99.3 % within 50 min under UV light and only showed a slight decrease after three cycles. The cellulose-mediated bioinspired approach was expected to introduce a method for preparing functional cellulose-based materials under mild conditions for various niche applications.