3D Printed Architectured Silicone Composites Containing a UV-Curable Rheological Modifier with Tailorable Structural Collapse

3D printed silicones, combining the unique physiochemical performances of silicones with the attractive design freedom of additive manufacturing, have aroused intensive interest from academia and industry owing to their attractive applications. Direct writing (DW) was the most used method to enable the 3D printing of silicones, but it was limited by its conflicting rheological requirements. Herein, we present novel design of an ultraviolet (UV)-thermal dual-cure ink for UV assisted DW of silicone composites. A UV curable rheological modifier was key to the ink design, which would not only increase the ink viscosity and yield stress substantially at low contents, but also further enhance its shape-retaining capability during printing by UV-assisted curing. As a result, challenging structures with good mechanical performances and isotropy were printable. Interestingly, the degree of structural collapse for the product could be controlled by tailoring the printing parameters, which proved to be a new design dimension for property manipulation of 3D-printed cellular architectures. Rheology of the inks and boundary conditions for structural collapse were discussed in detail. This work will open new opportunities for the development of 3D-printed silicones with customized architectures and tailored performances.