Stephanie Kwolek | Image Credit: Wikimedia Commons
While conducting research in the DuPont laboratory in 1965 in search of lighter, more durable materials, Stephanie Kwolek stumbled upon a substance that other scientists would consider a complete fiasco because of its uncharacteristic behavior. Instead of becoming a viscous liquid, the mixture appeared thin, milky, and watery. This observation alarmed Kwolek because an abnormal polymer structure usually indicates compositional instability and an inability to serve practical purposes. As reported by the American Chemical Society, Kwolek suspected that this odd milky substance was actually something else entirely.
This was a crucial juncture, as laboratory technicians had almost ruled out the substance entirely, fearing it could obstruct the spinneret, a machine used to create fibers from polymer solutions. However, as stated by the Smithsonian Lemelson Center, Kwolek remained insistent that the substance was worth testing rather than being disregarded altogether. This choice may seem obvious looking back now, but it was highly significant. Many lab tests are discontinued precisely because of unusual textures or appearances of substances.
Specifically, when Kwolek managed to turn the solution into a fiber, the resulting fiber immediately exhibited exceptional properties, according to the Smithsonian Institution. Kevlar fibers demonstrated unprecedented strength and rigidity compared with other materials available at the time. In this regard, it is necessary to note that the discovery was not due to chance, but on the contrary, at the moment when Kwolek discovered her creation, she already pursued a particular goal, namely creating light and strong fibers for use in tires and industrial reinforcement.
Indeed, as the Smithsonian points out, Kwolek repeatedly emphasized during her later interviews the importance of observation and perseverance over accidents in discovering Kevlar. In any case, Kevlar was possible due to experience, understanding, and willingness to verify an unexpected discovery. This discovery started from an extremely humble anomaly: an apparently wrong cloudy polymer mixture. Anyone other than Kwolek would simply ignore it because it does not fit laboratory conditions; however, she paid close attention to it, verified it, and eventually discovered one of the strongest artificial fibers from a liquid that nobody dared to use until Kwolek did.
This was a crucial juncture, as laboratory technicians had almost ruled out the substance entirely, fearing it could obstruct the spinneret, a machine used to create fibers from polymer solutions. However, as stated by the Smithsonian Lemelson Center, Kwolek remained insistent that the substance was worth testing rather than being disregarded altogether. This choice may seem obvious looking back now, but it was highly significant. Many lab tests are discontinued precisely because of unusual textures or appearances of substances.
Stephanie Kwolek | Image Credit: Wikimedia Commons
The cloudiness came from unusual molecular alignment inside the polymer
Kwolek was working on liquid-crystalline polymer solutions, in which molecules align themselves in an orderly fashion, in contrast to other types of synthetic polymers, whose molecules are arranged in an entangled pattern, as reported by the American Chemical Society. This property of the molecules provided the basis for Kevlar's exceptional strength; thus, it could be inferred that the cloudy appearance was caused by an unorthodox arrangement of the molecules, allowing them to transmit tension through the resulting thread more efficiently. Therefore, it is evident that not only the unusual look but also the subsequent properties were explained by the chemical composition of the substance.Specifically, when Kwolek managed to turn the solution into a fiber, the resulting fiber immediately exhibited exceptional properties, according to the Smithsonian Institution. Kevlar fibers demonstrated unprecedented strength and rigidity compared with other materials available at the time. In this regard, it is necessary to note that the discovery was not due to chance, but on the contrary, at the moment when Kwolek discovered her creation, she already pursued a particular goal, namely creating light and strong fibers for use in tires and industrial reinforcement.
Stephanie Kwolek | Image Credit: Wikimedia Commons
Kevlar eventually became one of the world’s most recognizable high-strength fibers
The polymer that came to be known as Kevlar was first commercially produced in the early 1970s and became increasingly recognized for its use in applications requiring high strength and low weight. According to the Lemelson-MIT Program, "Kevlar was about five times stronger than steel based on its weight," meaning it became useful for a wide variety of materials, including clothing, aerospace products, cables, and industrial reinforcements. However, its importance went beyond simply the commercial development of just this particular product. It showed how the behavior of liquid-crystalline polymers led to entirely new classes of materials.Indeed, as the Smithsonian points out, Kwolek repeatedly emphasized during her later interviews the importance of observation and perseverance over accidents in discovering Kevlar. In any case, Kevlar was possible due to experience, understanding, and willingness to verify an unexpected discovery. This discovery started from an extremely humble anomaly: an apparently wrong cloudy polymer mixture. Anyone other than Kwolek would simply ignore it because it does not fit laboratory conditions; however, she paid close attention to it, verified it, and eventually discovered one of the strongest artificial fibers from a liquid that nobody dared to use until Kwolek did.
