Paul John Flory

Location: Basement Floor, West Wing, South Wall, Sequence 2

Source: Chemical Heritage Foundation

Flory was awarded the 1974 Nobel Prize in Chemistry "for his fundamental achievements, both theoretical and experimental, in the physical chemistry of macromolecules". After obtaining the Ph.D. at the Ohio State University (1934) Flory joined Carothers' (see portrait) research group at the DuPont company, where he was introduced to polymer research. Kinetic studies of condensation polymerization enabled him to calculate the "most probable distribution" of molecular sizes in the polymer by assuming, contrary to conventional wisdom of the time, that reactivity is largely independent of molecular chain length. Other major contributions include the concept of "chain transfer" in the kinetics of vinyl polymerization, a statistical theory of gel formation from monomers with more than two functional groups, the Flory-Huggins theory of polymer solution thermodynamics, and the "excluded volume effect" which causes significant expansion of polymer coils over what had been previously theorized, theories of rubber elasticity and of liquid crystals, and many more. Flory, more than any other individual, showed that the physical and chemical properties of macromolecules are as understandable as those of nonpolymers via the basic principles of kinetics, thermodynamics, and statistical mechanics. His two books "Principles of Polymer Chemistry" (1953) and "Statistical Mechanics of Chain Molecules" (1969) became "bibles" in the field.

Flory spent years in both academia and industry and in 1961 moved to Stanford University for the remainder of his career. Among his other honors besides the Nobel were the 1969 ACS Debye Award and the 1973 Gibbs and 1974 Priestley medals.