Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Sandwich-structured zein/PVA nanofiber membranes with a curcumin-functionalized core layer are fabricated via sequential electrospinning (outer-core-outer). The protective outer layers encapsulate the adhesive core, resolving its tackiness issue while preserving filtration functionality. The resulting membranes exhibit tunable fiber diameters, enhanced mechanical properties, and high filtration efficiency, offering a sustainable strategy for bio-based air filtration materials.

ABSTRACT
To address the adhesion problem of curcumin-containing zein fibers, sandwich-structured zein/poly(vinyl alcohol) (PVA) membranes with a curcumin-functionalized core layer were fabricated via sequential electrospinning (outer-core-outer). The core layer exhibited flattened and adhesive fibers, whereas encapsulation within protective outer layers yielded cylindrical, non-adhesive fibers with tunable diameters (0.43–1.0 μm). The sandwich membranes exhibited enhanced mechanical properties (tensile strength up to 4.67 MPa) and stable hydrophobicity. Filtration tests demonstrated > 95% efficiency for 0.3 μm particles and > 97% for particles ≥ 0.5 μm, with pressure drop values ranging from 7.03 to 7.56 mbar. Post-filtration imaging revealed that curcumin-containing membranes displayed dispersed particle deposition on individual fibers, while the curcumin-free outer layer showed extensive particle aggregation, indicating curcumin-induced particle anchoring. FTIR analysis confirmed curcumin-mediated hydrogen bonding and increased β-sheet content. The sandwich design resolves core layer adhesion while preserving filtration functionality, offering a sustainable strategy for bio-based air filtration materials.