Science Daily July 25, 2022
Protein based composites, such as nacre and bone, show astounding evolutionary capabilities, including tunable physical properties. These composites become insensitive to flaws as soon as the structural size reaches a critical length. A team of researchers in the US (Pennsylvania State University, Brown University) studied the assembly of atomistically thin inorganic sheets with genetically engineered polymeric proteins to achieve mechanically compliant and ultra-tough materials. Although bare inorganic nanosheets are brittle, they designed flexible composites with proteins, which are insensitive to flaws due to critical structural length scale (∼2 nm). These proteins, inspired by squid ring teeth, adhere to inorganic sheets via secondary structures which is essential for producing high stretchability and toughness. They found that the mechanical properties can be optimized by adjusting the protein molecular weight and tandem repetition. The mechanical responses greatly exceed the current state-of-the-art stretchability for layered composites by over a factor of three, demonstrating the promise of engineering materials with reconfigurable physical properties. Stretchable 2D composites could be used for flexible circuit boards, wearable devices and other equipment that requires strength and flexibility…read more. TECHNICAL ARTICLEÂ