How is spider silk doing wonders to make bulletproof armours?
The military might procure this very light body armor for the troops in ten years. The most recent form of armor that the American Army is considering is nowhere near what you might think. Aramid won't be replaced by some robust new chemical composition or with porcelain. It's made of spider silk.
The hardest fiber discovered in nature is spider silk. It can be used to create bulletproof vests because when stretched or pushed, it can sustain more energy than steel or nylon without tearing. Additionally biocompatible, it can be utilized to make artificial ligaments and surgical thread.
However, because spiders are difficult to breed, making spider silk is a difficult task. Making artificial copies has proven to be much more challenging; no attempts have so far come close to matching the original. Now, a group of researchers from the University of Trento, led by Nicola Maria Pugno and Gabriele Greco, have created the first synthetic fibers with strength comparable to that of spider webs.
Scientists have indeed altered bacteria or insect cells to create spidroins, the primary proteins that makeup spider silk. Controlling the solubility and assembly of those proteins is critical for producing fibers that can be employed in medical applications. For stronger connections, the writers created a variety of modified spidereins. After producing these modified versions using genetically modified Escherichia coli bacteria, they used spectrophotometric methods to look into the relationship between mechanical qualities and the transformed fiber structure. Pugno notes, "Our concern was if it was possible to alter this molecular chain and make fibers with different or better physical behavior. The activities and structure of proteins are partially dictated by the chain sequence of their amino acids.
Two fiber types showed toughness equal to that of native silk as a result of the designed spideroins, which produced fibers with higher tensile strength. With just four layers, the final material stopped a.22-caliber bullet that was traveling slowly. Modern bulletproof vests require 33 layers of Aramid to be effective.
The glass transition temperature is another characteristic of spider silk. Spider silk reaches a brittle point far earlier than other polymers, between -50 and -60 degrees Celsius. This implies that a silk parachute cord will perform well under abrupt loads in addition to remaining durable in subfreezing conditions. According to the "time-temperature superposition" theory in polymer chemistry, fibers with low glass transition temperatures will also be able to withstand abrupt dynamic stresses, similar to those experienced by a parachute rope.
Stay tuned to learn more about how science is doing wonders for humankind.