Photocurable coatings prepared by emulsion polymerization present chelating properties

Herein, we present a method to synthesize a photocurable metal chelating copolymer coating via emulsion polymerization to enable a facile coat/cure preparation of metal chelating materials. The copolymer coating was a poly(n-butyl acrylate) based polymer (79 mol %) synthesized by emulsion polymerization, with iminodiacetic acid (2 mol %) and benzophenone moieties (19 mol %) to impart metal chelating and photocrosslinking properties, respectively. The copolymer was applied onto polypropylene films and was photocured (365 nm, 225 mW/cm², 180 s) to produce metal chelating film. The resulting metal chelating film had activity towards Fe³⁺ by chelating 10.9 ± 1.9 nmol/cm², 47.9 ± 5.3 nmol/cm², and 156.0 ± 13.8 nmol/cm² of Fe³⁺ at pH 3.0, pH 4.0, and pH 5.0, respectively. The metal chelating film controlled transition metal induced ascorbic acid degradation by extending half-life of ascorbic acid degradation from 6 days to 20 days at pH 3.0, and from 3 days to 6 days at pH 5.0, demonstrating its potential as an antioxidant active packaging material. Despite the introduction of polar iminodiacetic acid chelating moieties, the poly(n-butyl acrylate) based coatings retained low surface energies (24.0 mN/m) necessary to mitigate fouling and enable product release in packaging applications. This work overcomes a major knowledge gap in the area of functional coatings, by demonstrating a method by which critical properties such as control of surface energy, retention of mechanical properties, and scalability are integrated into the structure of a functional coating. The photocurable polymer coatings as reported here enable scalable production of active materials with metal chelating functionality, with applications in water treatment, trace metal detection, protein purification, and active packaging.