Multiscaling for Molecular Models to Predict Lab Scale Sample Properties: A Review of Phenomenological Models

One of the defining features of biological materials is that they are highly hierarchical with different structures at different length scales. Often they are complex nanocomposites of soft fibrous polymeric phase and hard mineral phase. For instance, bone has up to seven levels of hierarchy and nacre shows up to six levels of hierarchal structure. In spite of complex hierarchical structures, the smallest building blocks in such biological materials are at the nanometer length scale. The extent of interfacial interaction and the interfacial arrangement are important determinants of the structure–function property relationship of biomaterials and influence the mechanical strength substantially. Challenges lie in identifying nature’s mechanisms behind imparting such properties and its pathways in fabricating and optimizing these composites. The key here is the formation of large amount of precisely and carefully designed organic–inorganic interfaces and synergy of mechanisms acting over multiple scales to distribute loads and damage, dissipate energy, and resist change in properties owing to damages such as cracking. This chapter presents a brief overview of the role of interfacial structural design and interfacial forces in imparting superior mechanical performance to hard biological materials. Focus is on understanding the underlying engineering principles of nature’s materials for use in biomedical engineering and biomaterial development.