Mechanics of Hierarchical Alpha-helix Based Materials: Nanomechanical Strength and Fracture Mechanisms

Catastrophic phenomena that afflict millions of lives all have mostly one common underlying theme: the breakdown of the basic constituents leading to the failure of its overall structure. While the failure of engineering materials has been studied extensively, the mechanisms of failure in biological systems are not well understood. Here we undertake a systematic bottom-up analysis of the structure and properties of alpha-helix based protein materials (PMs). We review and extend a mathematical model, which allows us to describe the deformation mechanics in dependence of the hierarchical geometrical architecture. This model, validated with atomistic simulations, enables us to identify structure-property links and to predict the behavior of highly diverse protein structures. Our work suggests that the hierarchical, nanostructured design enables PMs to unify seemingly contradicting material properties with high potential for various new bioinspired material concepts.