Nanoarchitected Biological and Bio-Inspired Composites—Mitigation of Catastrophic Damage

There is an increasing need for the development of multifunctional lightweight materials with high strength and toughness. Natural systems have evolved efficient strategies, exemplified in the biological tissues of numerous animal and plant species, to synthesize and construct composites from a limited selection of available starting materials that often exhibit exceptional mechanical properties that are similar, and frequently superior to, mechanical properties exhibited by many engineering materials. These biological systems have accomplished this feat by establishing controlled synthesis and hierarchical assembly of nano- to micro-scaled building blocks. This controlled synthesis and assembly require organic that is used to transport mineral precursors to organic scaffolds, which not only precisely guide the formation and phase development of minerals, but also significantly improve the mechanical performance of otherwise brittle materials.<br/><br/>In this work, we investigate organisms that have taken advantage of hundreds of millions of years of evolutionary changes to derive ceramic-polymer based biological structures, which are not only strong and tough, but also demonstrate additional functionalities such as wear resistance, self-healing, self-cooling, etc. All of this is controlled by underlying organic scaffolding that dictates the spatial and temporal deposition of mineral. We discuss the nucleation, growth and subsequent phase transformations of architected materials found in one system demonstrating extreme wear resistance. We also discuss a regio-specific architected structure that includes multiple convergent design features that synergistically impart exceptional damage mitigation under extreme strained conditions.<br/><br/>From the investigation of synthesis-structure-property relationships in these extreme performance organisms, we are now developing and fabricating multifunctional engineering materials that leverage the design features from Nature. Thus, inspired by the exquisite control of these biomineralized structures, we utilize organic templates to carefully orchestrate the synthesis of nanostructured materials. By modulating ratios of precursor and organic, as well as controlling other synthetic variables, we can tune morphologies which are subsequently implemented into engineered structures and subjected to mechanical testing. The results of these tests validate observations in the biological structures, demonstrating significant protection against impact and offer potential use in multifunctional applications.