Microstructure study of fractured polar bear hair for toughening, strengthening, stiffening designs via energy dissipation and crack deflection mechanisms in materials

Abstract

Polar bear hair is known for its superior thermal insulation properties protecting from frigid water and freezing weather conditions. However, this microscopy study on polar bear hair is related to the investigation of the crack stopping mechanisms within its structure following the toughening mechanism principle used by nature. The inhomogeneous structure of polar bear hair consists of fiber bundles, tubules, membranes, porous medulla, and cuticle layers. Precisely, these types of material constructions help impact energy dissipation to protect materials before the failure and save animals via its multifunctionality. The multiscale structures are the key to adopting different physical properties in distinct sizes, from thermal insulation to the toughening, strengthening, and stiffening mechanisms in material designs.