Enhancing Gelatin Film Properties Using Plasma-Activated Water

Gelatin films (GFs) are promising biodegradable alternatives to plastic packaging, but their high hydrophilicity and limited stability remain challenges. This study investigated plasma-activated water (PAW) to modify GFs’ properties. Distilled water (DW) and tap water (TAP) were plasma-treated for 30, 60, and 90 s using an atmospheric-pressure plasma jet and used to prepare GFs. The films were characterized in terms of water contact angle, solvent resistance, and surface morphology using SEM. The results showed that increasing PAW treatment time improved the hydrophobicity of the GFs, with PAW (DM)-90 achieving a water contact angle above 100°. SEM analysis revealed a smoother surface morphology for PAW-treated films compared with the untreated film. In the solvent-resistance test, the PAW (TAP)-90 film retained 4.0 mL of apple vinegar and 4.6 mL of olive oil after 15 min of immersion, compared with complete dissolution of the untreated film in apple vinegar. PAW (DM)-90 retained 4.4 mL of apple vinegar and 4.5 mL of olive oil under the same conditions. Hence, PAW improved the hydrophobicity and solvent resistance of GFs, with effects depending on treatment time and water composition. Overall, PAW offers a simple, sustainable approach for developing GFs for moisture-sensitive packaging and biomedical applications.