Stephanie Kwolek

• Born: July 31, 1923
• Birthplace: New Kensington, Pennsylvania
• Died: June 18, 2014
• Place of death: Wilmington, Delaware

American chemist

During her years as a DuPont chemist, Kwolek discovered a new branch of synthetic materials: liquid crystalline polymers. Her innovations in polymer science led to the development of the high-performance fiber Kevlar.

Primary field: Chemistry

Primary invention: Kevlar

Early Life

Stephanie Louise Kwolek was born in New Kensington, Pennsylvania, in 1923. Her parents, John and Nellie (Zajdel) Kwolek, immigrated to America from Poland when they were in their teens. John Kwolek was a foundry worker and amateur naturalist, and he encouraged his daughter to take a scientific interest in her surroundings. Together, the two explored the woods near their home, observing wildlife and collecting seeds, leaves, and flowers. At home, they studied and cataloged their botanical samples. The young Stephanie also enjoyed designing fashions, and she spent many hours sketching and making clothes for her dolls.

John Kwolek died when his daughter was ten years old, leaving his wife to raise Stephanie and her younger brother alone. To support the family, Nellie Kwolek found a job as a kitchenware assembly-line worker at the local Alcoa plant. As Stephanie grew older, she developed an interest in becoming an educator. She took to teaching math, reading, and writing to the other children in her neighborhood. She showed an affinity for the sciences during her school years, and by the time she headed for college in 1942, she had plans to become a doctor or a chemist.

Kwolek attended Margaret Morrison Carnegie College in Pittsburgh, the women’s college of the Carnegie Institute of Technology (now the coed Carnegie Mellon University). During her studies there, which were funded by scholarships, she realized that she would be unable to afford medical school. She decided that after graduation she would seek work as a chemist to earn money for later graduate studies in medicine. With that goal in mind, she majored in chemistry and minored in biology. Kwolek received her bachelor’s degree in 1946.

Life’s Work

Job opportunities in scientific and technical fields had opened up for women during World War II, and Kwolek interviewed with several research companies. Ultimately, she found a position with E. I. du Pont de Nemours and Company, which hired her as a research chemist for its textile fibers laboratory in Buffalo, New York.

Kwolek thrived in the intellectually engaging environment at DuPont. She and her colleagues were working to create new synthetic polymers (long-chained molecules), and DuPont’s research facility was the site of pioneering work. She and her coworkers helped one another and learned from each other. DuPont maintained a top-notch research library and invited professors to come discuss their latest research with laboratory staff. Kwolek so enjoyed her work as a research chemist that she decided not to pursue a career in medicine after all. She would remain with DuPont for the next forty years.

Although DuPont employed Kwolek and other women in a traditionally male field, women in postwar America generally found it hard to build and advance careers or to gain recognition in scientific or technical areas. Many of Kwolek’s female coworkers left the company after a few years to become homemakers and mothers; others, frustrated with limited opportunities for advancement, moved on to careers in teaching. Kwolek, who never married, stuck with her job despite unequal treatment. She received her first promotion after she had worked for DuPont for fifteen years.

In 1950, Kwolek was one of several employees at the Buffalo plant who earned a transfer to DuPont’s newly opened Pioneering Research Laboratory in Wilmington, Delaware. There, in the Textile Fibers Department, the research team created and tested hundreds of thousands of new synthetic polymers.

Kwolek’s early work at DuPont focused on discovering polymers that would dissolve at low heat so that they could be spun into fibers at room temperature. Her advances in low-temperature processes for preparing condensation polymers laid the groundwork for the discovery of several of DuPont’s commercial products, including Lycra spandex, the flame-resistant material Nomex, and the multipurpose film Kapton.

In 1964, in the face of predicted gasoline shortages, DuPont set a goal to find a strong, lightweight, high-performance fiber for use in automobile tires. Replacing the heavy steel reinforcement in tires with a lightweight, textile-type fiber would improve gas mileage. Other chemists seemed uninterested in piloting the task, so Kwolek took on the challenge. The polymer needed to be stable at high temperatures and resistant to acids and bases. One of her experiments yielded surprising results. After synthesizing two aromatic polymers that subsequently refused to melt, Kwolek decided to use a solvent to dissolve them into liquid. However, when she mixed one of the polymers with the solvent, she did not get the clear, syrupy solution she expected from a flexible polymer chain. Instead, the resulting fluid was thin—almost like water—and hazy. She tried filtering the solution, but it retained its milky appearance.

Kwolek submitted the solution to a coworker who operated the lab’s spinneret, a device used to spin polymer solutions into fiber. He initially refused, convinced that the solution was not cohesive enough to spin and fearful that the cloudy liquid was full of suspended particles that would clog his equipment. When she finally persuaded him to try, the solution spun flawlessly. She submitted the resulting fiber to the physical test lab, which found it to be surprisingly strong and stiff. Heat-treating it, she discovered, intensified its properties. Kwolek resynthesized and retested the new fiber repeatedly before she announced her results.

Kwolek had stumbled upon a new branch of synthetics: liquid crystalline polymers. She had also synthesized something new: a para-aramid fiber. DuPont recognized the commercial potential of the new fibers and set out to create one that was right for commercial production. Lab staff went to work experimenting with other liquid crystalline solutions, thinking up applications for the new fibers and developing new equipment for spinning, testing, and cutting them. After more than half a decade of research and refinement, a commercially viable fiber emerged that was less dense than fiberglass but far stronger than steel. Kwolek applied for a patent for the fiber, which DuPont would dub Kevlar, in 1971. The patent was granted in 1974, and bullet-resistant Kevlar vests went on the market a year later.

Kwolek continued to research polymers at DuPont until her retirement in 1986. She was the holder or coholder of seventeen US patents; these include one for the spinning method that made commercial aramid fibers possible and five for the prototype polymer from which Kevlar was developed.

After retirement, Kwolek continued to work part-time as a consultant. She also lectured, mentored, and participated in education outreach activities to encourage young people in science.

Kwolek died on June 18, 2014, in Wilmington, Delaware, at the age of ninety.

Impact

Kwolek revolutionized chemistry with her discovery of liquid crystalline polymers. By laying the technological foundations for Kevlar body armor, she has also saved thousands of lives. However, Kwolek’s impact was not limited to her pioneering discoveries. She dedicated her postretirement years to mentoring female scientists and encouraging children, particularly girls, to pursue careers in science. She not only lectured about her life and work but also welcomed curious students into her home and took phone calls from children needing homework help. Her scientific curiosity, persistence, and determination made her an excellent role model who showed how science can provide opportunities for both intellectual challenges and valuable contributions to society.

Kwolek’s work earned her multiple honorary degrees and several major awards and distinctions. In 1994, she was named a Kilby Laureate for her revolutionary discoveries. In 1995, she was among the first recipients of the US Patent and Trademark Office’s newly established American Innovator Award. The following year, President Bill Clinton awarded her the country’s highest honor for technological achievement, the National Medal of Technology. In 1997, she became the second woman to receive the American Chemical Society’s Perkin Medal for her innovative work in applied chemistry, and she was inducted into the Plastics Hall of Fame. She was the 1999 recipient of the Lemelson-MIT Lifetime Achievement Award. She was an inductee of the National Inventors Hall of Fame (1995), the Women in Technology International Hall of Fame (1996), and the National Women’s Hall of Fame (2003).

Bibliography

Brown, David E. Inventing Modern America: From the Microwave to the Mouse. MIT Press, 2002. The chapter devoted to Kwolek presents an overview of her career at DuPont. A sidebar describes Kevlar’s use in sporting equipment. Photographs, list of sources and further reading, index.

Macdonald, Anne L. Feminine Ingenuity: How Women Inventors Changed America. Ballantine Books, 1992. The author interviews Kwolek in conjunction with the US Patent and Trademark Office’s 1990 special exhibit, “A Woman’s Place Is in the Patent Office,” at which Kwolek was a featured speaker. Bibliography, patents list, notes, index.

Pearce, Jeremy. "Stephanie L. Kwolek, Inventor of Kevlar, Is Dead at 90." The New York Times, 20 June 2014, www.nytimes.com/2014/06/21/business/stephanie-l-kwolek-inventor-of-kevlar-is-dead-at-90.html. Accessed 26 Oct. 2017.

Selle, Robert R. “Stephanie Kwolek: The Woman Who Created Kevlar.” World and I, vol. 19, no. 3, 2004, p. 44. An outstanding article on the inventor. Includes an especially clear and easy-to-understand description of liquid crystals. An ideal selection for the lay reader who wants to know more about the science behind Kevlar.

Vare, Ethlie Ann, and Greg Ptacek. Patently Female: From AZT to TV Dinners—Stories of Women Inventors and Their Breakthrough Discoveries. Wiley, 2002. Includes a brief, interview-based article on Kwolek, Kevlar, and what it was like to be a woman scientist in the mid-twentieth century. Photo, time line, list of organizations and online resources related to female inventors, index.

Vare, Ethlie Ann, and Greg Ptacek. Women Inventors and Their Discoveries. Oliver Press, 1993. The chapter on Kwolek, written for a young-adult audience, is one of the better detailed profiles of the inventor available in print. Photographs, bibliography, index.