Replicating 3D printed structures into functional materials

Three‐dimensional (3D) printing is gaining wide attention recently. It is particularly effective in fabricating topographically complicated structures on a small scale. However, the library of 3D printable material is highly limited which heavily hindered its further applications. Herein, we developed a convenient method to replicate the 3D‐printed structures into different functional materials. Consequently, many unprintable materials can be readily made into arbitrary geometry without reengineering their printability nor developing new 3D printing methods. These materials are thermally curable, chemically crosslinkable, or liquid/solid phase change at mild temperatures, such as polydimethylsiloxane, polyacrylamide, and paraffin. 3D structures with multiscale sizes and topographic complexity including a trifurcating network, an octahedron lattice, a Mario figure and a tetrahedron framework array were used for demonstration here. Our method shows a high fidelity during the replication and the replica can remain the high‐resolution of feature from a two‐photon polymerization 3D printer, which can generate 3D structures with resolution down to 1 μm or even smaller. In addition, electroless plating of metal in the internal walls of the mold can allow us to further shrink feature sizes in the final replica, which suggests an approach to obtain resolutions beyond the 3D printer at the start. The image shows the fabrication of a 3D object with functional materials using replication strategy. The process involves four steps: molding, burnaway of the master structure, casting and removal of the mold. A nickel mold formed by electroplating on the surface of the 3D printed master, and the interior master was burnaway to create room for functional materials casting. Eventually, the nickel mold was removed to retrieve the replica.