Characterization of bacterial cellulose composite films incorporated with bulk chitosan and chitosan nanoparticles: A comparative study

[Display omitted] •Novel bacterial cellulose/poly (vinyl alcohol)/chitosan films were developed.•The effects of chitosan as a bulk solution and nanoparticles were compared.•Incorporation of chitosan nanoparticles provided the best antibacterial activity.•Bulk chitosan improved the mechanical properties of the films.•Chitosan nanoparticles enhanced optical barrier properties against UV radiation. Ternary composite films containing bulk chitosan (CS) and chitosan nanoparticles (CSNPs) with different concentrations were prepared using bacterial cellulose/poly(vinyl alcohol) as the base film and the composites films were compared. The micromorphology and mechanical, physical, chemical, antibacterial, and optical barrier properties of the composite films were compared. CS incorporation improved the mechanical properties, as the maximum tensile strength was increased to 130.55 ± 9.42 MPa. The dense structure of CSNPs prevented water diffusion and lessened the water content of the composite membranes. The inclusion of CS and CSNPs both reduced the water solubility and water vapor permeability. CS-doped films possessed good transparency, while CSNPs had better ultraviolet-barrier properties (3.84 % of transmittance at 200–280 nm). In addition, CSNPs-embedded membranes exhibited prominent antibacterial properties against Escherichia coli and Staphylococcus aureus, which were much greater than those of CS composite membranes with a maximum bacteriostatic diameter of 10.33 ± 1.55 mm.