Abstract
Highly elastic silicone foams, especially those with tunable properties and multifunctionality, are of great interest in numerous fields. However, the liquid nature of silicone precursors and the complicated foaming process hinder the realization of its three‐dimensional (3D) printability. Herein, a series of silicone foams with outstanding performance with regards to elasticity, wetting and sensing properties, multifunctionality, and tunability is generated by direct ink writing. Viscoelastic inks are achieved from direct dispersion of sodium chloride in a unique silicone precursor solution. The 3D‐architectured silicone rubber exhibits open‐celled trimodal porosity, which offers ultraelasticity with hyper compressibility/cycling endurance (near‐zero stress/strain loss under 90% compression or 1000 compression cycles), excellent stretchability (210% strain), and superhydrophobicity. The resulting foam is demonstrated to be multifunctional, such that it can work as an oil sorbent with super capacity (1320%) and customizable soft sensor after absorption of carbon nanotubes on the foam surface. The strategy enables tunability of mechanical strength, elasticity, stretchability, and absorbing capacity, while printing different materials together offers property gradients as an extra dimension of tunability. The first 3D printed silicone foam, which serves an important step toward its application expansion, is achieved.