Hydrophobic-to-Hydrophilic Transition of Polyethylene Surface via Salicylic Acid Grafting

Polyethylene is widely used in flexible packaging, but its hydrophobic and inert surface limits its compatibility with environmentally friendly water-based inks and paints.Conventional methods improve wettability only temporarily and with limited control.Here, we introduce a surface functionalization method in which salicylic acid is grafted onto polyethylene films through an aluminum-mediated alkylation process compatible with continuous film processing.Infrared-softened polyethylene films were sequentially sprayed with AlCl 3 and salicylic acid.Reaction occurrence was confirmed by chemical and morphological analyses, revealing the in situ formation of aluminum salicylate complexes anchored to the polyethylene surface.Wettability tests demonstrated enhanced compatibility with water-based paints.