Ambient condition and oxygen-tolerant photopolymerization from near-UV to blue light via naphthimide–borate synergy

Abstract

Ambient photopolymerization remains hindered by oxygen inhibition, particularly in submicron films and under low-intensity 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.