Molecular Design of Biobased, Printable Monomers for Two-Photon Polymerization.

This study reports the strategic molecular design of a range of novel multi-acrylate monomers derived from the terpenoids nopol and verbenol, and their successful use in two-photon polymerization (2PP). This design process allowed the identification of structures most appropriate for use in additive manufacturing (AM) resins. This was achieved by deriving new synthesis routes that enabled the fabrication of monomers with bespoke numbers and placements of vinyl groups, which were then shown to dictate the level of success achieved in resin-based AM processing. By identifying the correct molecular design, it was demonstrated via 2PP that structures with uniform composition, smooth surfaces, and finely resolved features could be printed, as confirmed by scanning electron microscopy (SEM). 2PP is a high-precision 3D-printing technique for fabricating complex micro- and nano-scale structures. Despite its potential in functional devices, advanced manufacturing, and biomedical applications, the range of biobased monomers suitable for 2PP remains limited, and they are typically derived from petrochemical sources. This study also demonstrated that terpene and terpenoid reagents, which are abundant and renewable natural compounds, offer a promising platform for developing biobased, multifunctional monomers for AM.