Synthesis and characterization of a thioxanthone derivative photoinitiator with a dynamic disulfide bond and in situ synthesis of AuNps within a polymer matrix

Abstract

We present the synthesis and characterization of a novel thioxanthone disulfide derivative, dihydroxy thioxanthone disulfide [OH-TX-S-]2, as a photoinitiator. We emphasize its efficiency in free radical polymerization and its ability to facilitate the in-situ synthesis of gold nanoparticles (AuNps) within a polymer matrix. UV-Vis and fluorescence spectroscopy techniques were used to investigate the photophysical properties of [OH-TX-S-]2, a new photoinitiator consisting of dynamic disulfide bonds. The fluorescence quantum yield was 0.35 compared to 0.06 for unsubstituted thioxanthone. When irradiated, [OH-TX-S-]2generates thiyl radicals, which initiate the photopolymerization reactions of acrylates and methacrylates. Indeed, good conversion percentage values were obtained for photoinitiated polymerization of methyl methacrylate as monoacrylate and also multifunctional acrylates namely epoxydiacrylate diluted with TPGDA and 1,6-Hexanediol diacrylate. Furthermore, its role in the photoreduction of gold salts to AuNps has been established. Scanning electron microscopy (SEM) determined the size, shape, and distribution of the produced AuNps within the polymer matrix. These results collectively indicate the potential of [OH-TX-S-]2as both a photoinitiator and a photo- reducing agent for the development of advanced materials in functional coatings for various applications.