Institut Charles Sadron (ICS), 23 rue du Loess, BP 84047, 67034 Strasbourg Cédex 2, France
Équipe "Théorie et Simulation des Polymères" (ETSP)

Heros in Polymer Science

1. Leo Baekeland (1863-1944):

In 1909 Belgian-born Leo Hendrik Baekeland began small-scale production of a resin formed by the combination of phenol with formaldehyde. Mixing this resin with suitable fillers and then applying heat and pressure, Baekeland created Bakelite. Bakelite is a thermoset, a material that holds its shape permanently once it is formed and cannot be remolded.

2. Henri Benoit (1921-):

Neutron scattering of polymers, experimental confirmation of static properties: Kratky plot (Kratky plot q^2 S(q) vs. q).

3. Wallace Hume Carothers (1896-1937)

Critics of Staudinger's macromolecular theory of polymers often argued that giant molecules could not be made. This premise was put to the test by a young industrial chemist in America, Wallace Hume Carothers (1896-1937). With his research group at the Du Pont Experimental Station, Carothers synthesized and analyzed an extensive series of new polymeric substances, including polyesters, neoprenes, and nylons. He succeeded in 1930, and his success silenced one of the main criticisms of Staudinger's theory. It was merely coincidence that one of the synthetic macromolecules Carothers created happened to behave like natural silk. The next five years were spent looking for a synthetic polymer that would be a practical silk substitute. Success came in 1935 in the form of a polymer that would become known as Nylon.

4. Francis Crick (1916-2003) and James Watson (1928-): Nobel Prize in physiology or medicine in 1962

Crick's (right of figure) early work involved the X-ray crystallographic study of helical proteins, work that no doubt readied him to consider helices in other biomolecules. When James Watson joined his research group, the two became friends and fruitful collaborators. In 1953 James Watson (left of figure) and Francis Crick determined that the DNA molecule is shaped like a double helix, based on their examination of X-ray crystallographic data obtained by Rosalind Franklin (1920-1958) while working in the laboratory of Maurice Wilkins (1916-). This model allowed Watson and Crick to hypothesize a mechanism for DNA replication in which two strands of the double helix separate, each becoming the template for the production of a new strand.

5. Des Cloizeau:

6. Pierre-Gilles de Gennes: Nobel prize in Physics 1991

Scaling concepts, Polymer dynamics, Repation. He wrote a very influential book on Scaling concepts in Polymer Physics.

7. Sam Edwards:

Edwards hamiltonian.

Description (RPA) for screening of excluded volume interactions: no correlations beyond $\xi \propto 1/\rho^{1/2}$

8. Paul Flory (1910-1985): Nobel prize in Chemistry 1974

Physical Chemist with extraordinairy mathematical skills. Tough and precise worker putting the statistical mechanical description of polymers on firm mathematical grounds. Flory studied chemistry as an undergraduate at Manchester College and earned a doctorate in physical chemistry from the Ohio State University in 1934. He then went to work for DuPont, where he became involved in polymer chemistry under the direction of Carothers. Since Carothers was an organic chemist, Flory's abilities in physical chemistry and mathematics complemented well those of his mentor. Flory worked with Carothers to develop the basic principles of polymerization kinetics and the statistics of molecular mass distribution in polymer samples, among other things.

A year after the death of Carothers in 1937, Flory left DuPont for an academic career, returning to industry for a few years during World War II to work on the development of synthetic rubber for the war effort. In postwar academia he continued to develop his theories on the conformation of polymer chains in solution and produced his well-known book Principles of Polymer Chemistry, [F53] which is still the classic reference for polymer chemistry.

Quite a number of physical models and notions are due to him:

• Swollen chain exponent for dilute polymers
• Ideality hypothesis for dense polymers: Polymer chains in the melt are stongly entangled and are therefore Gaussian!
• Various lattice models for stiff, crystalline polymers and simple phase transitions which have been solved by him within mean-field approximation
• Mathematical theory of the creation of polymer networks, in which polymer fluids form cross-links and become, like rubber, elastic.
• Elegant statistical and kinetic considerations explained the role of end groups in polymer formation.

9. Thomas Graham (1805-1869)

In 1861 the British chemist Thomas Graham (1805-1869) noted an unusual property of some organic compounds such as starches and cellulose (wood fiber). When dissolved in solutions, they would not pass through fine filters. Nor could they be purified into a crystalline form. Graham believed that these substances represented a completely different organization of matter. He called them colloids, after kolla, the Greek word for glue. Incorrectly, Graham thought that cellulose and other colloids consisted not of molecules with an unusual number of atoms, but of large numbers of structurally simple molecules held together by "association." Association forces were not as strong as those forces binding the atoms of a molecule together. Yet they were sufficiently powerful to keep colloids from behaving like their "crystalloid" chemical relatives. After Graham, two generations of chemists would disregard the possibility that the sticky impurities fouling their distillations were actually giant molecules.

10. Alan J. Heeger (1936-), Alan MacDiarmid (1927-), Hideki Shirakawa (1936-) : Nobel Prize in Chemistry 2000

They shared their Nobel Prize for their discovery and development of conductive polymers. Most polymers are insulators, which is a good thing, because they are often used to insulate electrical wires. But in the late 1970s it was discovered that polymers can also conduct electricity. This can be achieved either through the addition of carbon or metal flakes or by adding chemicals like iodine and sulfur trifluoride to the polymer chain.

11. Robert S. Langer (1948-):

While the study of materials has long been at the center of what we think of as polymer science, macromolecular theory was born out of the study of biomaterials, and it's only fitting that one of the most active research frontiers in polymer science is that of bioactive synthetic materials. Langer has specialized in controlled drug delivery and tissue engineering. Much of Langer's research has been in biomedical applications of polymers. His later research has led to the development of a number of novel biodegradable polymers with medical applications. One of these resulted in a drug-delivery system for the treatment of brain cancer.

12. Herman Mark (1895-1985)

Along with Hermann Staudinger and Wallace Carothers, Herman Mark can be credited as a cofounder of polymer science. In the 1920s together with Kurt Meyer (1883-1952) he used X-ray crystallography to examine the internal structure of cellulose and other polymers. Their work convinced researchers that cellulose and other high polymers have structures larger than a single repeat unit.

Staudinger and Mark disagreed about the shape and properties which a macromolecule has. Staudinger proposed a rigid, crystalline form, like that of an uncooked strand of spaghetti. Mark, holding a model of Staudinger's molecule in this 1986 photograph, believed that the polymer would be much more flexible in its behavior, taking on an appearance more like that of a cooked strand of spaghetti. Mark's view has proven correct for most polymers.

The Mark-Houwink-Sakurada relationship describing the relationship between a polymer's solution viscosity and its molecular weight was another of his early discoveries.

13. Giulio Natta (1903-1979):

Shortly after Karl Ziegler's group obtained their new polyethylene, Giulio Natta announced that his laboratory in Milan had used a Ziegler catalyst to obtain a stereoregular polypropylene. See Ziegler-Natta catalysts.

14. Herrmann Staudinger (1881-1965): Nobel prize in Chemistry 1953

In the early 20th century German scientist Hermann Staudinger challenged the aggregate theory of polymers. In work beginning around 1920 he showed that polymers are in fact composed of many small, repeating units of monomers held together by covalent bonds. Staudinger was unpopular in his home country because of his outspoken criticism of Germany's use of poison gas in World War I, and his ideas were rejected by many in the scientific community, which at the time supported the aggregate theory. Staudinger would spend 15 years gathering evidence for his theory and arguing for its acceptance by the scientific community.

Staudinger proposed long-chain formulas for rubber and several other compounds, calling this group of materials "high polymers" (because of the large number of units making up each chain) or, as he preferred, macromolecules. Staudinger also derived a mathematical formula to explain the relationship between macromolecular viscosity and a dissolved polymer's molecular weight, a measure of the size of the molecule. This formula proved to be a powerful theoretical argument in the raging scientic battle.

15. Svedberg (1884-1971):

The Swedish chemist Svedberg developed an ultracentrifuge, which spun samples of colloidal solutions so rapidly that forces 100,000 times as strong as earth's normal gravity separated particles in solution. Very accurate determinations of molecular weight could be made with the new machine. Svedberg discovered that hemoglobin had a molecular weight of over 66,000--four times the highest weight ever assigned to it before.

16. Stockmeyer:

17. Karl Ziegler (1898-1973):

A major advance in polymer synthesis was the development of catalysts that exactly controlled the positioning of atoms attached to polymer chains. In 1953 a research team led by German chemist Karl Ziegler discovered that organic compounds of metals, such as aluminum alkyl, enabled the gas ethylene to polymerize at room temperature and normal atmospheric pressure. Polyethylene had been a commercially successful plastic for a decade before Ziegler's findings, but no one had ever produced it without exposing the ethylene to high pressures and temperatures, expensive conditions in commercial operation. See Ziegler-Natta polymerization.

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