Facile Photo and Thermal Two-Stage Curing for High-Performance 3D Printing of Poly(Dimethylsiloxane).

Three-dimensional (3D) printing of poly(dimethylsiloxane) (PDMS) is realized with a two-state curing strategy, i.e., photocuring for additively manufacturing high-precision architectures followed by thermal cross-linking for high-performance objects, taking Sylgard-184 as an example. In the mixture of base and curing agent of Sylgard-184, the photocuring ingredient methacrylated PDMS is incorporated to form hybrid inks with not only high-efficiency UV curing ability but also moderate rheological properties for 3D printing. The inks are then used to additively manufacture high-precision architectures by UV-assisted direct ink writing. Various architectures such as lattices and honeycombs, channels that can be used as microfluidics, and pressure-proof pipes with a feature size of ≈100 µm, can be readily printed. Thereafter, thermal cross-linking at elevated temperature is conducted to obtain the 3D PDMS objects with comparable properties to Sylgard-184. The facile, universal two-stage approach to 3D printing of PDMS can facilitate the development of microfluidics, flexible electronics, soft robots, and so on.