Rapid and High-Precision Photoinduced 3D Printing Enabled by Thioacetal Mediated Cationic Degenerate Chain Transfer Polymerization

Abstract

Cationic photopolymerization offers inherent advantages for additive manufacturing, including oxygen tolerance and darkcuring capability, yet its practical implementation in high-resolution 3D printing remains limited by the lack of molecularlevel control. Herein, we report a photoacid generator (PAG)-induced cationic degenerate chain transfer polymerization of vinyl ethers mediated by thioacetals under visible light (405 nm). The system exhibits rapid polymerization kinetics, tunable molecular weights (Mn = 3100-33700), narrow molecular-weight distributions (Ð = 1.30-1.67), and clear living characteristics, as evidenced by pseudofirst-order kinetics and successful chain extension. Integration of this chemistry into digital light processing (DLP) 3D printing via incorporation of a divinyl ether crosslinker affords photocurable resins capable of highresolution fabrication with excellent dimensional (~57 μ m) and structural fidelity. Systematic modulation of resin composition enables precise tuning of mechanical properties, yielding materials spanning brittle, tough, and elastomeric regimes. This work establishes a versatile and operationally simple controlled cationic photopolymerization strategy for advanced additive manufacturing and expands the toolbox for designing functional polymer networks with programmable properties.