Eco-engineering of all-cellulose functional nanocomposites through partial dissolution of bacterial nanocellulose membranes

All-cellulose composites (ACCs) are promising sustainable alternatives to petroleum-based materials, but their functionalization and property control remains challenging. In this study, multifunctional ACCs were fabricated from bacterial nanocellulose (BNC) membranes via controlled partial dissolution using an aqueous NaOH/urea system. By varying dissolution time (5–20 min), composites with tunable structure and performance were produced without toxic solvents. Increasing dissolution times yielded thinner, denser, and more translucent films, with visible-light transmittance up to ∼56% at 700 nm and reduced crystallinity (85% to ∼79%). Mechanical properties were tunable, with Young’s modulus decreased from 1.63 to 0.76 GPa, tensile strength from ∼ 150 to 46 MPa, and elongation at break increased from ∼11% to ∼17%. Partial dissolution also enhanced enzymatic biodegradability, enabling complete degradation within 4–7 days. The optimal sample (BNC-ACC10) was further functionalized with phytic acid (1.0–10.0% v/v), a bio-based additive, to introduce active properties. These composites showed strong antioxidant activity (up to 64% DPPH scavenging), antibacterial effects against Staphylococcus aureus (MRSA) and Escherichia coli , and improved flame retardancy. Despite slight reductions in stiffness, films retained structural integrity and transparency. This eco-engineering strategy enables scalable production of multifunctional, fully cellulosic nanocomposites with potential applications in textiles, packaging, and biomedical fields.