An insight into the toughness modulus enhancement of high-performance knotted microfibers through the correspondence analysis

A variety of applications, spanning from structural or biomedical engineering to flexible electronics, require the development of materials able to withstand high load and, at the same time, accommodate high strain before failure. While strength and toughness are often self-excluding properties in man-made materials, they can be efficiently combined by nature, which provides source of inspiration for novel materials design. Herein this paper, we pursue a bio-inspired approach, based on the introduction of a mechanical sink, such as a running knot, to improve the toughness modulus of high-performance polymeric microfibres. These are then enriched with additional smart features, such as a viscoelastic coating, surface roughening or a combination of those, to amplify the beneficial effect of the knot introduction. The role played by all such features on the mechanical performances of the prepared fibre samples, namely load at failure and toughness modulus increase, is then evaluated through a statistical technique, known as correspondence analysis (CA). While this exploratory analysis is widely adopted in biology, ecology, neuroscience or genetics, applications in structural or mechanical engineering are still rare. Here, we show that CA can be a powerful tool for the design of materials provided with enhanced toughness without losing strength.