Multifunction polyurethane elastomers with high mechanical robustness and exceptional crack tolerance performance based on bi-incompatible soft segment and dynamic coordination bonds

Abstract

Elastomers with high strength and super toughness are widely used in the aerospace, flexible electronics, biomedical, and other fields. However, the development of healable and recyclable elastomers with high strength, high toughness, and excellent crack resistance remains a significant challenge. In this work, we successfully synthesized a multifunctional silicone-based elastomer (SiPUU-HPA@Fe 1/3 ) with outstanding mechanical properties, selfhealing capabilities and recyclability by combining incompatible the biocompatible polycarbonate (PCDL) segments and the flexible polydimethylsiloxane (PDMS) segments as well as metal coordination bonds. Owing to the presence of the phase separation structures and dynamic coordination interaction, the optimized SiPUU-HPA@Fe 1/3 elastomer exhibits a high tensile strength of 45.5 MPa, an ultrahigh toughness of 412.5 MJ/m 3 , and an exceptional fracture energy of 179.3 kJ/m 2 . Additionally, the SiPUU-HPA@Fe 1/3 elastomers can be healed and recycled to regain their original mechanical strength and integrity under heating.Furthermore, the SiPUU-HPA@Fe 1/3 elastomer demonstrates excellent antibacterial properties and no cytotoxic effects observed. Finally, a soft SiPUU-HPA@Fe 1/3 /Li based strain sensor was developed by combining SiPUU-HPA@Fe 1/3 with the conductive ionic lithium bis(trifluoromethane)sulfonimide (LiTFSI), and demonstrate remarkable sensing capability to diverse human body motions. This research provides ideas for the design of polyurethane elastomer with high mechanical properties and multiple functions, and the elastomers are expected to be used in emerging fields such as biomedical and flexible electronics.