Water‐Soluble Reversible Photo‐Cross‐Linking Polymer Dielectrics

Abstract

AbstractEffective recycling of mixed materials requires the separation of the different components without the need for toxic solvents. One approach involves utilizing a water‐soluble coating with reversible photo‐cross‐linkers, making it robust until end of life where it can then be dissolved in water after de‐cross‐linking. Here, a novel coumarin methacrylate monomer and its nitroxide‐mediated copolymerization to create poly((methacrylic acid)‐co‐(styrene sulfonate)‐co‐(coumarin methacrylate)) for water‐soluble thin films are reported. Under exposure to light, the coumarin functional groups produce reversible [2+2] cycloadditions which cross‐link the resulting polymer films, making them no longer water soluble. Characterization of reversible cross‐linking behavior is reported through changes in contact angle and in situ rheological characterization. The resulting polymers are successfully integrated into metal–insulator–metal capacitors, demonstrating the potential use for water‐soluble reversible photo‐cross‐linkable dielectric materials for organic electronics.