Size effect-inspired fabrication of konjac glucomannan/polycaprolactone fiber films for antibacterial food packaging

The exploration of new methods to produce food packaging with excellent physicochemical and antibacterial properties is of great scientific and technological interest. Here, we successfully prepare the food packaging films that are composed of konjac glucomannan (KGM), poly(ε-caprolactone) (PCL) and silver nanoparticles (AgNPs) via microfluidic spinning technology (MST). The obtained fiber films (average fiber diameter: 7.8 ± 0.2 μm) exhibit excellent antibacterial activities against S. aureus (34 ± 0.71 mm) and E. coli (39 ± 5.66 mm), which is ascribed to the good swelling of KGM in KGM/PCL/AgNPs fiber films (SD: 37.86 ± 6.87%). Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) are employed to study the interactions between polymers. Thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), water vapor permeability (WVP), and mechanical property measurements are conducted to evaluate the thermal properties, hydrophilicity and mechanical performances of the films. The results show that the films are thermal stable and relatively hydrophobic (WVP: 5.8 × 10^-6 ± 1.44 g/(m·h·kPa), WCA: 101.0°) as well as have terrific elongation at break (EB: 223.59 ± 98.14%), which is beneficial for food packaging. This strategy provides a facile and green pathway for the construction of promising antibacterial food packaging.