Rapid and High-Resolution 3D Printing via Photoacid Genera-tor induced Cationic RAFT Polymerization

Abstract Vinyl ethers, while being typical monomers for living cationic polymerization, have limited commercial use due to poor mechanical properties of their polymers at room temperature. We explored the use of photoacid generators (PAGs) to induce cationic reversible addition-fragmentation chain transfer (RAFT) polymerization for the rapid high-resolution 3D printing of various vinyl ethers. The process demonstrated controlled molecular weights and narrow molecular weight distributions (MWD), with monomer conversions exceeding 90% in minutes. Incorporating a crosslinker enabled 3D printing at speeds up to 8.46 cm h-1 with layer thicknesses as thin as 50 microns. The mechanical properties of the printed objects were tunable by adjusting resin components, allowing for a range of material characteristics from brittle to elastomeric (tensile strength ranging from 13.9 to 31.7 MPa, Young's modulus ranging from 185.6 to 992.7 MPa and elongation at break ranging from 2.8 to 68.3%). Moreover, polymer welding facilitated the creation of gradient materials, showcasing the potential for engineered applications of poly(vinyl ethers).