Electrospinning versus solvent casting: Enhancing the mechanical properties of pyrogallol-loaded polyvinyl alcohol-pectin-potato starch films.

Abstract

Developing a biopolymer with strong mechanical and functional properties remains a key challenge. In this study, polyvinyl alcohol (PVA, 4% w/v), pectin (P, 2% w/v), potato starch (PS, 0.5% w/v), and pyrogallol (Py, 1% w/v) films were fabricated via electrospinning (ES) and solvent casting (SC). Based on this, two sets of films were developed: electrospun nanofibers (ESNF) and solvent cast (SC) films. Among the developed formulations, F8 (ESNF-PVA-P-PS-Py) exhibited higher tensile strength (TS) (43 ± 0.7 MPa) (5-fold increase) and Young's modulus (YM) (2009 ± 80 MPa) (200-fold increase), compared to SC films (p < 0.05). ESNF showed slightly higher antioxidant activity (DPPH, 95 ± 0.3% (1.02-fold increase)) and antibacterial activity (Kirby-Bauer disc diffusion assay) against Staphylococcus aureus (38.5 ± 0.5 mm) and Klebsiella pneumoniae (26.5 ± 0.5 mm) (1.2-fold increase) than SC films and validated using an amoxicillin disc. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and Nuclear magnetic resonance (NMR) of the ESNF and SC films showed minor peak shifts, indicating structural integrity and compatibility of the film components. Field-emission scanning electron microscopy (FE-SEM) analysis demonstrated the porous nanofibrous structure of the ESNF and the dense, non-porous matrix of the SC films. The ESNF demonstrated an average diameter of 79.36 ± 39.3 nm (F1) and 109.85 ± 32.64 nm (F8) with porosities of 28.12% (F1) and 7.66% (F8), respectively. Release kinetics demonstrated a 1.44-fold higher rate of release of phenolic components in F8 (5.9 ± 0.05 mg/g) than in F16. Overall, ESNF exhibited improved mechanical, functional, and biodegradable performance compared to SC films, demonstrating their effectiveness as an alternative to conventional plastics.