Fabrication and characterizations of electrospun cellulose/CeO2 nanocomposite membranes

Nanocomposite membranes based on electrospun-cellulose (EC) composites combined with cerium oxide (CeO2) nanoparticles (NPs) were fabricated by electrospinning using cellulose acetate (CA) as a precursor. CeO2 NPs were initially synthesized via cellulose nitrate template. After removing the template and any residual by calcination at 500 degrees C, the nanocubic CeO2 NPs were obtained with average sizes of 20.40 +/- 3.8 nm and then incorporated into cellulose nanofibers (CNFs) by mixing with CA solution. Subsequently, the obtained CA/CeO2 nanocomposite membrane was formed via the electrospinning and then converted to the EC/CeO2 nanocomposite membrane by being treated with a NaOH ethanolic solution. FTIR analysis confirmed the stepwise conversion of the acetyl group in CA structure to the hydroxyl groups of cellulose. The fabricated nanocomposite membranes characterized via FE-SEM and AFM, evaluating that the addition of CeO2 NPs incorporated into the fabricated CNFs resulted in changing their average fiber diameter without the exfoliation of CeO2 NPs. The average fiber diameter of the EC and EC/CeO2 nanocomposite membranes with 0.5, 1.0, and 1.5 wt% CeO2 contents was estimated to be 206 +/- 66, 189 +/- 47, 178 +/- 52, and 147 +/- 108 nm, respectively. However, it was observed that, at 1.5 wt% of CeO2 NP contents, the bead-like formation appeared, leading to enhancement of water uptake capacities up to 260.11 +/- 15.93%, meanwhile the EC membrane exhibited the water uptake capacities of 203.77 +/- 11.11%. In addition, the antibacterial activity of EC nanocomposite membranes was conducted against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results indicated that incorporating CeO2 NPs into the CNF matrix via electrospinning does not exhibit the distinct antibacterial activities of EC. The effect of the CeO2 NPs incorporated in EC nanocomposite membranes was further discussed.