Inspired by the properties of nacre - the opalescent biological composite found inside seashells - researchers have engineered a new glass that's ductile yet tough, and highly impact-resistant. The mother-of-pearl-bioinspired material more than doubles the impact tolerance of widely used tempered and laminated glass, whilst maintaining all the unique qualities that make glass one of the most ubiquitous materials of our everyday lives. Prized for its optical, thermal, electrical, chemical and mechanical properties, glass is found in a wide variety of everything, from high-rise buildings to mobile phones. However, for all these strengths, glass is an inherently brittle material. While tempered and laminated glasses can be more impact-resistant than conventional glass, these materials, too, generally lack the toughness required for applications in which material failure begets high consequences. To build a better glass, Zhen Yin and colleagues looked to nacre, the naturally impact-resistant material incorporated into the shells of mollusks, which shields their soft bodies from strong predator jaws. The key to the material's natural toughness lies in its unique construction. Built like a brick wall, nacre is composed of stacked layers of microscopic mineral tablets bonded by biopolymers, which can slide past one another when under stress. Yin et al. engineered a laminated glass with similar capabilities using borosilicate glass sheets that were layered and bonded using a synthetic ethylene-vinyl acetate. By mimicking the "tablet sliding mechanism" of nacre, large amounts of applied mechanical energy - which would otherwise cause glass to shatter - can be dissipated. According to the results, the nacre-like glass is two to three times more impact-resistant than tempered and laminated glass. In a related Perspective, Kyriaki Datsiou discuss the limits of the new glass and avenues in which it could be improved.
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Science