View source for Paul Flory

{{Short description|American chemist (1910–1985)}}

{{Use mdy dates|date=July 2018}}
{{Infobox scientist
| image             = Paul Flory 1973.jpg
| caption           = Flory in 1973
| birth_name        = Paul John Flory
| birth_date        = {{Birth date|1910|6|19|mf=y}}
| birth_place       = [[Sterling, Illinois]], U.S.
| death_date        = {{Death date and age|1985|9|9|1910|6|19|mf=y}}
| death_place       = [[Big Sur, California]], U.S.
| nationality       = [[Americans|America]]
| field             = [[Physical chemistry]] of [[polymer]]s
| work_institution  = [[DuPont]], [[Stanford University]], [[Carnegie Mellon University]], [[Cornell University]]
| alma_mater        = [[Manchester University (Indiana)]] and [[Ohio State University]]
| doctoral_advisor  = [[Herrick L. Johnston]]
| known_for         = [[Polymer chemistry]]<br/>[[Polymer physics]]<br/>[[Flory convention]]<br/>[[Flory–Fox equation]]<br/>[[Flory–Huggins solution theory]]<br/>[[Flory–Rehner equation]]<br/>[[Flory–Schulz distribution]]<br/>[[Flory–Stockmayer theory]]<br/>[[Random sequential adsorption]]<br/>[[Star-shaped polymer]]<br/>[[Self-avoiding walk]]
| prizes            = {{no wrap|[[Nobel Prize for Chemistry]] (1974)<br/>[[National Medal of Science]] (1974)<br/>[[Priestley Medal]] (1974)<br/>[[Perkin Medal]] (1977)<ref name="SCI Perkin Medal">{{cite web|title=SCI Perkin Medal|url=https://www.sciencehistory.org/sci-perkin-medal|website=[[Science History Institute]]|date=May 31, 2016 |access-date=March 24, 2018}}</ref><br/>[[Elliott Cresson Medal]] (1971)<br/>[[Peter Debye Award]] (1969)<br/>[[Charles Goodyear Medal]] (1968)<br/>[[William H. Nichols Medal]] (1962)<br />[[Colwyn medal]] (1954)}}
}}

'''Paul John Flory''' (June 19, 1910 – September 9, 1985) was an American chemist and [[Nobel laureate]] who was known for his work in the field of [[polymers]], or [[macromolecules]].<ref name="auto2">{{cite journal|author=Pecora, Robert|title=Obituary: Paul John Flory|journal=Physics Today|date=November 1986|volume=39|issue=11|pages=116–117|doi=10.1063/1.2815221|bibcode=1986PhT....39k.116P|doi-access=free}}</ref> He was a pioneer in understanding the behavior of [[polymer]]s in solution, and won the [[Nobel Prize in Chemistry]] in 1974 "for his fundamental achievements, both theoretical and experimental, in the physical chemistry of macromolecules".<ref>{{Cite web |title=The Nobel Prize in Chemistry 1974 |url=https://www.nobelprize.org/prizes/chemistry/1974/summary/ |access-date=2023-07-11 |website=NobelPrize.org |language=en-US}}</ref>

==Biography==

===Personal life===
Flory was born in Sterling, Illinois, on June 19, 1910 to Ezra Flory and Martha Brumbaugh. His father worked as a clergyman-educator, and his mother was a school teacher. His ancestors were [[Germans|German]] [[Huguenots]], who traced their roots back to [[Alsace]].<ref>{{cite web |url=https://www.nobelprize.org/prizes/physics/1989/ramsey/biographical/ |title=Paul J. Flory – Biographical |date=1974 |website=nobelprize.org |access-date=January 28, 2024 |quote=I was born on 19 June, 1910, in Sterling, Illinois, of Huguenot-German parentage, mine being the sixth generation native to America.}}</ref><ref>{{cite journal |last1=Johnson |first1=William S. |last2=Stockmayer |first2=Walter H. |last3=Taube |first3=Henry |date=2002 |title=Paul John Flory 1910–1985 |url=https://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/flory-paul.pdf |journal=Biographical Memoirs of the National Academy of Sciences |page=4 |access-date=January 28, 2024 |quote=The Flory family traces its roots back to Alsace, then England, later to Pennsylvania, and then to Ohio.}}</ref> He first gained an interest in science from Carl W Holl, who was a chemistry professor at [[Manchester University (Indiana)|Manchester College]].  In 1936, he married Emily Catherine Tabor. They had three children together: Susan Springer, Melinda Groom and Paul John Flory, Jr.  His first position was at [[DuPont]] with [[Wallace Carothers]].<ref name="Mangravite">{{cite web|last1=Mangravite|first1=Andrew|title=Finding Aid to the Paul J. Flory papers, 1931–1985 bulk 1950–1978|url=http://othmerlib.sciencehistory.org/record=b1023972~S6|website=Science History Institute|date=2001|access-date=March 27, 2018|quote="Click on 'Paul J. Flory papers finding aid' for full finding aid."}}</ref><ref>Morris, Peter J. T. (1986) ''Polymer Pioneers: A Popular History of the Science and Technology of Large Molecules'' Center for History of Chemistry, Philadelphia. pp. 70–73. {{ISBN|0941901033}}</ref> He was posthumously inducted into the [[Alpha Chi Sigma]] Hall of Fame in 2002.<ref name="alphachisigma1"/> Flory died on September 9, 1985, following a heart attack.<ref>{{cite journal|last=Eisenberg|first=Henryk|title=Paul J. Flory (1910-1985)|journal=Nature|volume=317|pages=474|url=https://www.nature.com/articles/317474a0.pdf}}</ref> His wife Emily died in 2006 aged 94.

== Schooling ==
After graduating from [[Elgin High School (Illinois)|Elgin High School]] in 1927, Flory received a bachelor's degree from Manchester College (now Manchester University (Indiana) in 1931 and a Ph.D. from the [[Ohio State University]] in 1934.  He completed a years of master's study in organic chemistry under the supervision of Prof. Cecil E Boord,<ref name="auto1">{{Cite web|url=http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/flory-paul.pdf|title=Paul John Flory: A Biographical Memoir}}</ref> before moving into physical chemistry. Flory's doctoral thesis was on the photochemistry of nitric oxide, supervised by Prof. Herrick L. Johnston.<ref name="auto">{{Cite web |date=2023-06-15 |title=Paul J. Flory {{!}} Nobel Prize-Winning American Chemist {{!}} Britannica |url=https://www.britannica.com/biography/Paul-J-Flory |access-date=2023-07-11 |website=www.britannica.com |language=en}}</ref>

== Work ==
In 1934 Flory joined the Central Department of [[DuPont|Dupont and Company]] working with [[Wallace Carothers|Wallace H. Carothers]].<ref name="auto"/>  After Carothers' death in 1937, Flory worked for two years at the Basic Research Laboratory located in the University of Cincinnati.  During World War II, there was a need for research to develop synthetic rubber, so Flory joined the Esso Laboratories of the [[Standard Oil|Standard Oil Development Company]].<ref name="auto1"/>  From 1943 to 1948 Flory worked in the polymer research team of the Goodyear Tire and Rubber Company.<ref name="auto2"/>

In 1948, Flory gave the George Fisher Baker lectures at [[Cornell University]], and subsequently joined the university as a professor.<ref name="auto2"/> In 1957, Flory and his family moved to Pittsburgh, Pennsylvania, where Flory was executive director of research at the [[Mellon Institute of Industrial Research]].<ref name="auto2"/> In 1961, he took up a professorship at [[Stanford University]] in the department of chemistry. After retirement, Flory remained active in the world of chemistry, running research labs both in Stanford, and IBM.<ref name="auto2"/>

== Research ==

===Career and polymer science===
Flory's earliest work in polymer science was in the area of [[polymerization]] [[chemical kinetics|kinetics]] at the [[DuPont Experimental Station]].  In [[condensation polymerization]], he challenged the assumption that the reactivity of the end group decreased as the macromolecule grew, and by arguing that the reactivity was independent of the size, he was able to derive the result that the number of chains present decreased with size exponentially.  In [[addition polymerization]], he introduced the important concept of [[chain transfer]] to improve the kinetic equations and remove difficulties in understanding the polymer size distribution.

In 1938, after Carothers' death, Flory moved to the Basic Science Research Laboratory at the [[University of Cincinnati]].  There he developed a mathematical theory for the polymerization of compounds with more than two functional groups and the theory of polymer networks or [[gels]].  This led to the [[Flory-Stockmayer Theory|Flory-Stockmayer theory]] of gelation, which was equivalent to [[Percolation theory|percolation]] on the [[Bethe lattice]] and represents the first paper in the percolation field.

In 1940 he joined the [[Linden, NJ]] laboratory of the [[Standard Oil]] Development Company where he developed a statistical mechanical theory for polymer mixtures. In 1943 he left to join the research laboratories of [[Goodyear Tire and Rubber Company|Goodyear]] as head of a group on polymer fundamentals.  In the Spring of 1948 [[Peter Debye]], then chairman of the chemistry department at [[Cornell University]], invited Flory to give the annual Baker Lectures.  He then was offered a position with the faculty in the Fall of the same year.  He was initiated into the Tau chapter of [[Alpha Chi Sigma]] at Cornell in 1949.<ref name="alphachisigma1">[http://www.alphachisigma.org/page.aspx?pid=268 Fraternity – Awards – Hall of Fame]. Alpha Chi Sigma (May 23, 2018). Retrieved on 2018-07-17.</ref> At Cornell he elaborated and refined his Baker Lectures into his magnum opus, ''Principles of Polymer Chemistry'' which was published in 1953 by [[Cornell University Press]].  This quickly became a standard text for all workers in the field of polymers, and is still widely used to this day.

Flory introduced the concept of [[excluded volume]], coined by [[Werner Kuhn (chemist)|Werner Kuhn]] in 1934, to polymers. Excluded volume refers to the idea that one part of a long chain molecule can not occupy space that is already occupied by another part of the same molecule. Excluded volume causes the ends of a polymer chain in a solution to be further apart (on average) than they would be were there no excluded volume.  The recognition that excluded volume was an important factor in analyzing long-chain molecules in solutions provided an important conceptual breakthrough, and led to the explanation of several puzzling experimental results of the day. It also led to the concept of the [[theta solvent|theta point]], the set of conditions at which an experiment can be conducted that causes the excluded volume effect to be neutralized. At the theta point, the chain reverts to ideal chain characteristics – the long-range interactions arising from excluded volume are eliminated, allowing the experimenter to more easily measure short-range features such as structural geometry, bond rotation potentials, and steric interactions between near-neighboring groups. Flory correctly identified that the chain dimension in polymer melts would have the size computed for a chain in ideal solution if excluded volume interactions were neutralized by experimenting at the theta point.

Among his accomplishments are an original method for computing the probable size of a polymer in good solution, the [[Flory-Huggins Solution Theory]], the extension of polymer physics concepts to the field of liquid crystals, and the derivation of the [[Flory exponent]], which helps characterize the movement of polymers in solution.<ref name="auto2"/>

===The Flory convention===
:''see [[Flory convention]] for details.''
In modeling the position vectors of atoms in macromolecules it is often necessary to convert from [[Cartesian coordinates]] (x,y,z) to [[generalized coordinates]]. The Flory convention for defining the variables involved is usually employed. For an example, a peptide bond can be described by the x,y,z positions of every atom in this bond or the Flory convention can be used. Here one must know the [[bond length]]s <math>l_i</math>, [[bond angle]]s <math>\theta_i</math>, and the [[dihedral angle]]s <math>\phi_i</math>. Applying a vector conversion from the Cartesian coordinates to the generalized coordinates will describe the same three-dimensional structure using the Flory convention.

== Awards and honors ==
Flory was elected to the United States [[National Academy of Sciences]] in 1953 and the [[American Academy of Arts and Sciences]] in 1957.<ref>{{Cite web |title=Paul J. Flory |url=http://www.nasonline.org/member-directory/deceased-members/55700.html |access-date=2022-08-15 |website=www.nasonline.org}}</ref><ref>{{Cite web |title=Paul John Flory |url=https://www.amacad.org/person/paul-john-flory |access-date=2022-08-15 |website=American Academy of Arts & Sciences |language=en}}</ref> In 1968, he received the [[Charles Goodyear Medal]]. He also received the [[Priestley Medal]] and the Golden Plate Award of the [[Academy of Achievement|American Academy of Achievement]]<ref>{{cite web|title= Golden Plate Awardees of the American Academy of Achievement |website=www.achievement.org|publisher=[[American Academy of Achievement]]|url=https://achievement.org/our-history/golden-plate-awards/#science-exploration}}</ref> in 1974. He received the Carl-Dietrich-Harries-Medal for commendable scientific achievements in 1977.<ref>{{cite web |title=Carl-Dietrich-Harries-Medal for commendable scientific achievements |url=https://www.dkg-rubber.de/en/hall-of-fame.html?infoID=1481&periodID=79&rubrik=77 |website=dkg-rubber.de |publisher=DKG |access-date=2 July 2022}}</ref> Flory received the [[Nobel Prize in Chemistry]] in 1974 "for his fundamental achievements both theoretical and experimental, in the physical chemistry of the macromolecules."<ref>{{cite web |title=The Nobel Prize in Chemistry 1974 |url=https://www.nobelprize.org/prizes/chemistry/1974/summary/ |website=The Nobel Prize |publisher=Nobel media |access-date=24 July 2019}}</ref> Additionally in 1974 Flory was awarded the [[National Medal of Science]] in Physical Sciences. The medal was presented to him by President [[Gerald Ford]]. This award was given to him because of his research on the "formation and structure of polymeric substances".<ref>{{cite web |title=The President's National Medal of Science: Recipient Details |url=https://www.nsf.gov/od/nms/recip_details.jsp?recip_id=129 |website=National Medal of Science |publisher=National Science Foundation |access-date=24 July 2019}}</ref>

==Bibliography==
*Flory, Paul. (1953) ''Principles of Polymer Chemistry''. Cornell University Press. {{ISBN|0-8014-0134-8}}.
*Flory, Paul. (1969) ''Statistical Mechanics of Chain Molecules''. Interscience. {{ISBN|0-470-26495-0}}. Reissued 1989. {{ISBN|1-56990-019-1}}.
*Flory, Paul. (1985) ''Selected Works of Paul J. Flory''. Stanford Univ Press. {{ISBN|0-8047-1277-8}}.

== References ==
{{reflist|2}}

*Paul J. Flory – Facts. NobelPrize.org. Nobel Media AB 2019. Wed. 19 Jun 2019. <[https://www.nobelprize.org/prizes/chemistry/1974/flory/facts/ The Nobel Prize in Chemistry 1974]>
*Somsen, Geert. Paul J Flory. Encyclopædia Britannica. June 15, 2019. [https://www.britannica.com/biography/Paul-J-Flory Paul J. Flory | Nobel Prize-Winning American Chemist | Britannica]
*Paul John Flory. Stanford Chemistry. [https://chemistry.stanford.edu/people/flory].

==External links==
{{Commons category|Paul Flory}}
* Chemistry Tree: [https://web.archive.org/web/20141019175018/http://academictree.org/chemistry/peopleinfo.php?pid=52081 Paul J. Flory Details]
*{{Nobelprize}} A short autobiography of Paul Flory
*[https://www.nobelprize.org/prizes/chemistry/1974/flory/lecture/ Nobel lecture by Paul Flory]
*{{cite web|last1=Mangravite|first1=Andrew|title=Finding Aid to the Paul J. Flory papers, 1931–1985 bulk 1950–1978|url=http://othmerlib.sciencehistory.org/record=b1023972~S6|website=Science History Institute|date=2001|access-date=March 27, 2018|quote="Click on 'Paul J. Flory papers finding aid' for full finding aid."}}
*[http://www.oac.cdlib.org/findaid/ark:/13030/kt000030qk?query=paul%20j%20flory Paul J. Flory papers] at the [http://www.hoover.org/library-and-archives Hoover Institution Archives]
*[http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/flory-paul.pdf National Academy of Sciences Biographical Memoir]

{{Nobel Prize in Chemistry Laureates 1951-1975}}
{{1974 Nobel Prize winners}}
{{Authority control}}

{{DEFAULTSORT:Flory, Paul John}}
[[Category:1910 births]]
[[Category:1985 deaths]]
[[Category:American Nobel laureates]]
[[Category:American people of German descent]]
[[Category:American physical chemists]]
[[Category:Fellows of the American Physical Society]]
[[Category:Members of the American Philosophical Society]]
[[Category:Nobel laureates in Chemistry]]
[[Category:National Medal of Science laureates]]
[[Category:Ohio State University College of Arts and Sciences alumni]]
[[Category:People from Elgin, Illinois]]
[[Category:People from Sterling, Illinois]]
[[Category:Polymer scientists and engineers]]
[[Category:20th-century American chemists]]
[[Category:Manchester University (Indiana) alumni]]