Asymmetric Hard Domain-Induced Robust Resilient Biocompatible Self-Healable Waterborne Polyurethane for Biomedical Applications.

The synthesis of eco-friendly and biocompatible waterborne polyurethanes (WPUs) through judicious molecular engineering with supreme mechanical strength, good shape recoverability, and high self-healing efficiency is still a formidable challenge because of some mutually exclusive conflicts among these properties. Herein, we report a facile method to develop a transparent (80.57-91.48%), self-healable (efficiency 67-76%) WPU elastomer (strain 3297-6356%) with the highest reported mechanical toughness (436.1 MJ m), ultrahigh fracture energy (126.54 kJ m), and good shape recovery (95% within 40 s at 70 °C in water). These results were accomplished by introducing high-density hindered urea-based hydrogen bonds, an asymmetric alicyclic architecture (isophorone diisocyanate-isophorone diamine), and the glycerol ester of citric acid (a bio-based internal emulsifier) into the hard domains of the WPU. Most importantly, platelet adhesion activity, lactate dehydrogenase activity, and erythrocyte or red blood corpuscle lysis demonstrated the hemocompatibility of the developed elastomer. Simultaneously, the cellular viability (live/dead) assay and the cell proliferation (Alamar blue) assay of human dermal fibroblasts corroborated the biocompatibility under in vitro conditions. Furthermore, the synthesized WPUs showed melt re-processability with retention of mechanical strength (86.94%) and microbe-assisted biodegradation. The overall results, therefore, indicate that the developed WPU elastomer might be used as a potential smart biomaterial and coating for biomedical devices.