Stephanie Kwolek

Stephanie Louise Kwolek was an American polymer chemist whose laboratory curiosity and keen observation resulted in the invention of Kevlar—a material that has saved thousands of law enforcement officers, soldiers, and first responders worldwide. The daughter of Polish immigrants, Kwolek graduated from Carnegie Mellon University intending to save money for medical school, but fell in love with polymer chemistry after joining DuPont's Pioneering Research Laboratory in 1946.

In 1965, while seeking a lightweight, rigid synthetic fiber to reinforce radial automobile tires during fuel shortages, Kwolek dissolved poly-p-phenylene terephthalamide and observed that the solution was cloudy, milky, and watery rather than thick and clear like usual polymer solutions. Persuading a reluctant technician to spin the 'defective' solution through a spinneret, she produced a revolutionary synthetic fiber with incredible molecular alignment: Kevlar, five times stronger than steel of equal weight, heat-resistant, and flame-retardant. Inducted into the National Inventors Hall of Fame, Kwolek was only the fourth woman to receive the Perkin Medal.