Paul Flory

American chemist and Nobel laureate in polymer physical chemistry.

Quick Facts

Birth name: Paul John Flory
Born: 19 June 1910
Birthplace: Sterling, Illinois, U.S.
Died: 9 September 1985
Place of death: Big Sur, California, U.S.
Field: Physical chemistry of polymers
Workplaces: DuPont, Stanford University, Carnegie Mellon University, Cornell University
Education: Manchester University (Indiana), Ohio State University

Lore & Background

His doctoral thesis, supervised by Prof. Herrick L. Johnston, was on the photochemistry of nitric oxide. Flory's first position was at DuPont with Wallace Carothers. After retirement, he remained active, running research labs at Stanford and IBM.

Reader's Guide

Paul Flory's significance lies in his foundational contributions to polymer science, which transformed the understanding of macromolecules. His work on polymerization kinetics challenged prevailing assumptions, showing that end-group reactivity in condensation polymerization is independent of chain size, leading to exponential chain-length distributions. He introduced the concept of chain transfer in addition polymerization and developed the Flory-Stockmayer theory of gelation, a precursor to percolation theory. Flory's statistical mechanical theory for polymer mixtures (Flory-Huggins solution theory) and his treatment of excluded volume—the idea that chain segments cannot occupy the same space—provided crucial insights into polymer behavior in solution. He identified the theta point, where excluded volume effects are neutralized, allowing measurement of short-range molecular features. Flory's legacy endures in the Flory convention for describing macromolecular geometry and in the widespread application of his theories to polymers, liquid crystals, and materials science.