Ambient and Oxygen-Tolerant Photopolymerization from Near-UV to Blue Light via Naphthimide-Borate Synergy

Ambient photopolymerization remains hindered by oxygen inhibition, particularly in submicron films and under lowintensity visible light. Here, we report a synergistic photoinitiator system composed of alkyne-functionalized naphthalimide and a borate additive that enables oxygen-tolerant and rapid photopolymerization from near-UV to blue light. Upon light irradiation, photo-induced electron transfer (PET) between borate and naphthalimide simultaneously accelerates radical generation and neutralizes peroxyl species, forming a robust anti-oxygen mechanism. This system achieves efficient curing of submicron-thick resin films in air, reaching 69% retention within 1 s under 405 nm LED light at 35 mW/cm 2 , which far exceeds that of conventional phosphine oxide initiators (0%) and thiol-ene (~6%) systems under identical conditions, while micron-thick films achieve approximately 95% retention. The platform is broadly compatible with diverse resins-including epoxy acrylate, acrylated soybean oil, and polyurethane acrylate-and demonstrates excellent storage stability, scalability, and patterning resolution down to 0.4 μm under ambient conditions without inert gas protection. This work provides a generalizable strategy for oxygen-tolerant photopolymerization and ambient-condition photopolymerization.