Overcoming the brittleness of glass through bio-inspiration and micro-architecture

Abstract

Highly mineralized natural materials such as teeth or mollusk shells boast unusual combinations of stiffness, strength and toughness currently unmatched by engineering materials. While high mineral contents provide stiffness and hardness, these materials also contain weaker interfaces with intricate architectures, which can channel propagating cracks into toughening configurations. Here we report the implementation of these features into glass, using a laser engraving technique. Three-dimensional arrays of laser-generated microcracks can deflect and guide larger incoming cracks, following the concept of 'stamp holes'. Jigsawlike interfaces, infiltrated with polyurethane, furthermore channel cracks into interlocking configurations and pullout mechanisms, significantly enhancing energy dissipation and toughness. Compared with standard glass, which has no microstructure and is brittle, our bioinspired glass displays built-in mechanisms that make it more deformable and 200 times tougher. This bio-inspired approach, based on carefully architectured interfaces, provides a new pathway to toughening glasses, ceramics or other hard and brittle materials.

Two-photon–induced internal modification of silicon by erbium-doped fiber laser

“…Within the research on the interaction of laser beams with materials, the three-dimensional machining of transparent dielectric materials has received considerable attention [1][2][3][4][5][6][7][8]. This process is also referred to as the production of subsurface, bulk or internal modifications.…”

Engineering the translaminar fracture behaviour of thin-ply composites

“…Nanoparticles are used as inclusions in polymeric materials to deviate and branch the crack propagation pattern, therefore creating more complex fracture surfaces and increasing energy dissipation [18,19,20]. Mirkhalaf [21] 20 demonstrated how crack deflection induced by the presence of a 3D array of laser engraved micro-cracks can be used to control the crack propagation pattern and significantly increase the toughness of glass.…”

Hydraulic fracturing in cells and tissues: fracking meets cell biology

“…Conversely, biological architectures can provide new concepts for materials design, such as tough micro-architectured materials made out of brittle constituents inspired in sea shells [35], tough elastomer-hydrogel composites inspired in mammalian skin [36], or polymeric multifunctional self-healing materials [37]. From a materials perspective, a striking aspect of epithelial sheets subject to stretching is that the poroelastically-driven hydraulic fractures are small and distributed throughout the material, in contrast with most materials that fracture by localizing a single crack.…”