Biological Discoveries: Paper, A bioinspired optically transparent tough glass composite

Glasses have numerous applications due to their exceptional transparency, however, poor fracture and impact resistance limit their applications as an engineering material. One relatively recent approach to improve the mechanical properties of materials is through bio-inspiration. Structural biological composites such as nacre, the protective inner layer of mollusk shells, offer far superior mechanical properties relative to their constituents. This has motivated researchers to mimic the design principles in natural composites to create tough transparent materials. However, current bio-inspired materials lack fabrication scalability or offer poor optical transmission. Here, an efficient, scalable bulk process is developed for creating optically transparent tough composites, resulting in a nacreous glass composite material with a four-fold increase in fracture toughness and a three-fold increase in flexural strength compared to conventional structural glasses, and with a 73% of average optical transmittance. The composite consists of glass flakes and poly (methyl methacrylate) (PMMA) assembled utilizing a centrifuge-based fabrication method that aligns and compacts the flakes into layers. To optimize the transparency of the structure, the refractive indices of the PMMA and glass are matched. Based on the results, this nacreous glass composite is proposed as a potential alternative in diverse architectural, vehicular, and electronics applications.

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