Multifunctional Konjac Glucomannan Film Tuning by Gallic Acid Functionalization

Konjac glucomannan (KG) is a biocompatible polysaccharide with limited functional performance in its native form, motivating modification strategies to enhance its properties. This study investigates the effect of gallic acid (GA) functionalization on the structural, physicochemical, mechanical, antioxidant, and biological properties of KG-based films. FTIR analysis confirmed that GA interacts with KG primarily through non-covalent hydrogen bonding without disrupting the polymer backbone. Modification with GA enabled concentration-dependent tuning of surface energy, roughness, hydration behavior, and water vapor permeability. Mechanical testing revealed a significant increase in stiffness and tensile strength accompanied by reduced elongation at higher GA contents. Antioxidant activity was markedly enhanced even at low GA concentrations. All films exhibited excellent hemocompatibility, while cytocompatibility toward human fibroblasts depended on GA content. Optical analysis indicated moderate color changes without severe discoloration. Overall, GA functionalization effectively improves the functional performance of KG films while preserving polymer integrity. Hence, GA-modified KG films as promising candidates for biomedical applications (like wound dressing) requiring antioxidant activity, controlled hydration, and biocompatibility.