Light-Induced Thermal Decomposition of Alkoxyamines upon Infrared CO2 Laser: Toward Spatially Controlled Polymerization of Methacrylates in Laser Write Experiments

CT: Systems combining photopolymerization and thermal polymerization have already been reported in the literature. Upon near-infrared (NIR) light exposure, this principle of polymerization is called photoinduced thermal polymerization or photothermal polymerization. Thanks to an NIR dye used as the light-to-heat convertor (called hereafter a heater), an alkoxyamine (e.g., BlocBuilder-MA) is dissociated upon NIR light irradiation, initiating the free-radical polymerization of methacrylates. In the present paper, a novel approach is presented for the first time to decompose the alkoxyamine through a direct heat generation upon mid-infrared irradiation by a CO2 laser at 10.6 mu m. Compared with previous approaches, there is no additional heater used in this work, as the heat is directly generated by laser irradiation on the alkoxyamine/monomer system. The polymerization can be initiated for benchmark methacrylate monomers with spatial controllability, that is, only in the laser-irradiated area, opening the way for laser write or three-dimensional printing applications in the presence of fillers.