Cement-inspired readily fabricated water-strengthened polymeric materials

Polymeric materials have penetrated all aspects of society and play an irreplaceable role. However, there is an inherent contradiction between their mechanical properties and processing behavior. Here, inspired by cement, a crucial construction material renowned for its excellent fabricating behavior and self-strengthening properties, we have developed dynamic cross-linked poly(oxime-urethane) (CPOU). The synthesized CPOU showed good self-healing ability and 3D printability owing to the dynamic dissociation and re-association of oxime-carbamate bonds. Simple objects printed through the fused deposition modeling technique were able to be readily assembled into complex architectures through intrinsic self-healing. Furthermore, the self-strengthening of CPOU was successfully realized through multiple-step tandem reactions. The dissociation of dynamic oxime-carbamate bonds produced–NCO groups, which reacted with the surrounding water to form polar urea bonds in the polymer network, leading to an increase in the tensile strength of CPOU from 11.95 to 19.37 MPa. This work not only develops the polymers with combined self-healing, facile fabricating, and self-strengthening properties but also provides a new molecular strategy to modulate the properties of polymers, which could be potentially applied in diverse areas.