Bioinspired polyurethane structures with interfacial fluidity for improved impact attenuation

Superior impact toughness and enhanced strength of the brick-and-mortar design of nacre (mother-of-pearl), has made it a topic of intensive research in many fields of material science. Although numerous studies have demonstrated the mechanical robustness of the brick-and-mortar design, little is known about the two-dimensional impact attenuation characteristics of these structures. Herein, we develop brick-and-mortar based layered polyurethane structures for improved impact attenuation. In this study, layered structures of polyurethane were synthesized to mimic mechanics of nacre. The impact attenuation characteristics of these structures were then characterized using a comprehensive impact attenuation analysis. From the analysis, these nacre-inspired layered structures show up to 400% greater impact attenuation when compared to monolithic polyurethane. In addition, multi-parametric correlation analysis reveals that this improvement in impact attenuation is very strongly correlated to the interfacial fluidity within these structures and not friction damping. Given the nature of these results, we strongly believe that the presented work provides a creative strategy for designing, developing, and characterizing, compact and robust structures that provides penetration resistance while preventing impact forces from damaging supporting structures. This would be ideal for use in helmets, sport vests, and similar impact isolation applications.