Photoluminescent Self-Healable Waterborne Polyurethane/Mo and S Codoped Graphitic Carbon Nitride Nanocomposite with Bioimaging and Encryption Capability.

Creating polymers that combine various functions within a single system expands the potential applications of such polymeric materials. However, achieving polymer materials that possess simultaneously elevated strength, toughness, and self-healing capabilities, along with special properties, remains a significant challenge. The present study demonstrates the preparation of S and Mo codoped graphitic carbon nitride (g-C3N4) (Mo@S-CN) nanohybrid and the fabrication of self-healing waterborne polyurethane (SHWPU)/Mo@S-CN (SHWPU/NS) nanocomposites for advanced applications. Mo@S-CN is an intriguing combination of g-C3N4 nanosheets and molybdenum oxide (MoOx) nanorods, forming a complex lamellar structure. This unique arrangement significantly improves the inborn properties of SHWPU to an impressive degree, especially mechanical strength (28.37-34.11 MPa), fracture toughness (73.65-140.98 MJ m-2), and thermal stability (340.17-348.01 °C), and introduces fluorescence activity into the matrix. Interestingly, a representative SHWPU/NS0.5 film is so tough that a dumbbell of 15 kg, which is 53,003 times heavier than the weight of the film, can be successfully lifted without any significant crack. Remarkably, fluorescence activity is developed because of electronic excitations occurring within the repeating polymeric tris-triazine units of the Mo@S-CN nanohybrid. This fascinating feature was effectively harnessed by assessing the usability of aqueous dispersions of the Mo@S-CN nanohybrid and photoluminescent SHWPU/NS nanocomposites as sustainable stains for bioimaging of human dermal fibroblast cells and anticounterfeiting materials, respectively. The in vitro fluorescence tagging test showed blue emission from 365 nm excitation, green emission from 470 nm excitation, and red emission from 545 nm excitation. Most importantly, in vitro hemocompatibility assessment, in vitro cytocompatibility, cell proliferation assessment, and cellular morphology assessment supported the biocompatibility nature of the Mo@S-CN nanohybrid and SHWPU/NS nanocomposites. Thus, these materials can be used for advanced applications including bioimaging.

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-3), ultrahigh fracture energy (126.54 kJ m-2), 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.