New long-wavelength D–π-A–π-D chalcone photoinitiator for visible light polymerization with photobleaching and biocompatibility properties

Abstract

Four chalcones with large conjugated structures have been designed and synthesized. The large conjugated structures of the four chalcones give them excellent absorption properties in the visible region (λ_max = 407–483 nm, ε_max = 24600–60200 M⁻¹ cm⁻¹) and excellent intramolecular charge transfer characteristics. After forming a three-component photoinitiation system with iodine and an amine, the free radical polymerization of various acrylates was effectively initiated under UV-LED and blue LED irradiation, with a final double bond conversion rate of 92%. The photochemical reaction mechanism was determined using steady-state photolysis, fluorescence quenching, cyclic voltammetry and ESR experiments. In addition, the chalcones were found to have good photobleaching properties and biocompatibility through photoinduced degradation and cytotoxicity experiments. These excellent properties demonstrate that these chalcones have great promise for applications in the field of photopolymerization.