Dual-functional waterborne coatings featuring enhanced anticorrosion and persistent luminescence enabled by rare-earth doping

To address the dual challenges of traditional rare-earth luminescent materials (poor moisture resistance, aging stability) and conventional coatings (environmental hazards, insufficient corrosion protection) for industrial applications, a novel waterborne composite coating with persistent luminescence and excellent anticorrosion performance was developed. Using APSA-UTPCZrP (AUZ), a surface-modified 2D layered nanomodifier validated in previous work to enhance anticorrosion while retaining waterborne polyurethane (WPU)’s environmental friendliness; urushiol titanium polymer (UTP), strontium magnesium silicate (Mss) and strontium aluminate (As) phosphors were efficiently dispersed in WPU via amphiphilic sodium alginate (APSA), which ensures WPU compatibility through hydrophilic segments and phosphor adsorption via hydrophobic moieties. The 5Mss@AUZ/WPU exhibited synergistically enhanced performance: 8 h post-excitation luminescence duration (via AUZ-sensitized rare-earth ion energy-level transitions), alongside improved thermal stability, hydrophobicity, and chemical resistance. Crucially, it demonstrated outstanding anticorrosion performance: impedance modulus of 2.64 × 10 6  Ω∙cm 2 , corrosion rate of 1.38 × 10 −5  mm/year, and protection efficiency of 99.56%, stemming from AUZ's physical barrier (layered structure) and rare-earth ions' chemical inhibition (dense passive oxide layers). The As-modified counterpart achieved a higher impedance modulus (3.99 × 10 6  Ω∙cm 2 ) due to stronger As ions chelation. Notably, the 5As@AUZ/WPU coating maintained bright and stable luminescence under harsh conditions (acid/alkali/salt immersion, UV irradiation), attributed to its robust corrosion-resistant barrier protecting internal luminescent crystals. This study elucidates the synergistic dual-functional mechanism between AUZ and rare-earth phosphors, enabling long-afterglow luminescence and robust corrosion protection, thus offering a sustainable materials platform for underwater detection and marine engineering.