Paul John Flory | Biography

Paul John Flory, widely recognized as the founder of the science of polymers, was born in Sterling, Illinois, on June 19, 1910. His parents were Ezra Flory, a clergyman and educator, and Martha (Brumbaugh) Flory, a former school teacher. Ezra and Martha's ancestors were German, but they had resided in the United States for six generations.

After graduation from Elgin High School, Flory enrolled at his mother's alma mater, Manchester College, in North Manchester, Indiana. The college was small, with an enrollment of only 600. He earned his bachelor's degree in only three years. An important influence on Flory at Manchester was chemistry professor Carl W. Holl. Holl apparently convinced Flory to pursue a graduate program in chemistry. In June of 1931, therefore, Flory entered Ohio State University and, in spite of an inadequate background in mathematics and chemistry, earned his master's degree in organic chemistry in less than three months. He then began work immediately on a doctorate, but switched to the field of physical chemistry. He completed his research on the photochemistry of nitric oxide and was granted his Ph.D. in 1934.

After graduation, Flory accepted a job at the chemical giant, Du Pont, as a research chemist. There he was assigned to a research team headed by Wallace H. Carothers, who was later to invent the process for making nylon and neoprene. Flory's opportunity to study polymers was ironic in that, prior to this job, he knew next to nothing about the subject.

Flory's work on the Carothers team placed him at the leading edge of chemical research. Chemists had only recently begun to unravel the structure of macromolecules, very large molecules with hundreds or thousands of atoms, and then to understand their relationship to polymers, molecules that have chemically combined to become a single, larger molecule. The study of polymers was even more difficult than that of macromolecules because, while the latter are very large in size, they have definite chemical compositions that are always the same for any one substance. Polymers, on the other hand, have variable size and composition. For example, polyethylene, a common polymer, can consist of anywhere from a few hundred to many thousands of the same basic unit (monomer), arranged always in a straight chain or with cross links between chains.

With his background in both organic and physical chemistry, Flory was the logical person to be assigned the responsibility of learning more about the physical structure of polymer molecules. That task was made more difficult by the variability of size and shape from one polymer molecule to another--even among those of the same substance. Flory's solution to this problem was to make use of statistical mechanics to average out the properties of different molecules. That technique had already been applied to polymers by the Swiss chemical physicist Werner Kuhn and two Austrian scientists, Herman Mark and Eugene Guth. But Flory really developed the method to its highest point in his research at Du Pont.

During his four years at Du Pont, Flory made a number of advances in the understanding of polymer structure and reactions. He made the rather surprising discovery, for example, that the rate at which polymers react chemically is not affected by the size of the molecules of which they are made. In 1937, he discovered that a growing polymeric chain is able to terminate its own growth and start a new chain by reacting with other molecules that are present in the reaction, such as those of the solvent. While working at Du Pont, Flory met and, on March 7, 1936, married Emily Catherine Tabor. The Florys had two daughters, Susan and Melinda, and a son, Paul John, Jr. Flory's work at Du Pont came to an unexpected halt when, during one of his periodic bouts of depression, Carothers committed suicide in 1937. Although deeply affected by the tragedy, Flory stayed on for another year before resigning to accept a job as research associate with the Basic Science Research Laboratory at the University of Cincinnati. His most important achievement there was the development of a theory that explains the process of gelation, which involves cross-linking in polymers to form a gel-like substance.

Shortly after World War II began, Flory accepted an offer from the Esso (now Exxon) Laboratories of the Standard Oil Development Company to do research on rubber. It was apparent to many American chemists and government officials that the spread of war to the Pacific would imperil, if not totally cut off, the United States' supply of natural rubber. A massive crash program was initiated, therefore, to develop synthetic substitutes for natural rubber. Flory's approach was to learn enough information about the nature of rubber molecules to be able to predict in advance which synthetic products were likely to be good candidates as synthetic substitutes ("elastomers"). One result of this research was the discovery of a method by which the structure of polymers can be studied. Flory found that when polymers are immersed in a solvent, they tend to expand in such a way that, at some point, their molecular structure is relatively easy to observe.

In 1943, Flory was offered an opportunity to become the leader of a small team doing basic research on rubber at the Goodyear Tire and Rubber Company in Akron, Ohio. He accepted that offer and remained at Goodyear until 1948. One of his discoveries there was that irregularities in the molecular structure of rubber can significantly affect the tensile strength of the material.

In 1948, Flory was invited by Peter Debye, the chair of Cornell University's department of chemistry, to give the prestigious George Fisher Baker Lectures in Chemistry. Debye subsequently offered him a regular appointment in the chemistry department beginning in the fall of 1948, and Flory accepted. The Baker Lectures he presented were compiled and published by Cornell University Press in 1953 as Principles of Polymer Chemistry. Flory continued his studies of polymers at Cornell and made two useful discoveries. One was that for each polymer solution there is some temperature at which the molecular structure of the polymer is most easily studied. Flory called that temperature the theta point, although it is now more widely known as the Flory temperature. Flory also refined a method developed earlier by the German chemist Hermann Staudinger to discover the configuration of polymer molecules using viscosity. Finally, in 1956, he published one of the first papers ever written on the subject of liquid crystals, a material ubiquitous in today's world, but one that was not to be developed in practice until more than a decade after Flory's paper was published.

In 1957, Flory became executive director of research at the Mellon Institute of Industrial Research in Pittsburgh. His charge at Mellon was to create and develop a program of basic research, a focus that had been absent from that institution, where applied research and development had always been of primary importance. Eventually, Flory realized that he disliked administrative work and was making little progress in refocusing Mellon on basic research. Thus, when offered the opportunity in 1961, he resigned from Mellon to accept a post at the department of chemistry at Stanford University. Five years later, he was appointed Stanford's first J. G. Jackson-C. J. Wood Professor of Chemistry. When he retired from Stanford in 1975, he was named J. G. Jackson-C. J. Wood Professor Emeritus. In 1974, a year before his official retirement, Flory won three of the highest awards given for chemistry--the National Medal of Science, the American Chemical Society's Priestley Medal, and the Nobel Prize in chemistry.

Flory's influence on the chemical profession extended far beyond his own research work. He was widely respected as an outstanding teacher who thoroughly enjoyed working with his graduate students. A number of his students later went on to take important positions in academic institutions and industrial organizations around the nation. His influence was also felt as a result of his two books, Principles of Polymer Chemistry, published in 1953, and Statistical Mechanics of Chain Molecules, published in 1969.

Flory was also active in the political arena, especially after his retirement in 1975. He and his wife decided to use the prestige of the Nobel Prize to work in support of human rights, especially in the former Soviet Union and throughout Eastern Europe. He served on the Committee on Human Rights of the National Academy of Sciences from 1979 to 1984 and was a delegate to the 1980 Scientific Forum in Hamburg, at which the topic of human rights was discussed. At one point, Flory offered himself to the Soviet government as a hostage if it would allow Soviet scientist Andrei Sakharov's wife, Yelena Bonner, to come to the West for medical treatment. The Soviets declined the offer, but eventually did allow Bonner to receive the necessary treatment in Italy and the United States.

Flory died on September 8, 1985, while working at his weekend home in Big Sur, California.