Bioinspired toughening of soft elastomer via embedded three‐dimensional printing

Abstract The interest in soft elastomers has been revived because they are needed in the emerging soft robotics and wearable devices. It is imperative to adjust the mechanical properties of elastomeric materials for real‐life applications as well as to develop an approach to construct more complex and customized architectures. In this study, an embedded extrusion‐based three‐dimensional (3D) printing method was used to prepare silicone elastomeric composites. Cellulose nanocrystals were introduced to tailor the rheology of the ink and serve as reinforcements after solidification. The printing paths were carefully designed to write Bouligand structures, which have been widely found in arthropod cuticles and fish scales because of their exceptional damage resistance. Compared with the pure elastomer and randomly distributed composites, the 3D‐printed elastomeric composites with bioinspired structures exhibited simultaneously enhanced stiffness, extensibility, and toughness. This strategy may be extended to the realization of other biomimetic designs and paves the way for soft material manufacturing.