Biographical Memoirs Volume 90 (2009) / Chapter Skim
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JOHN DOUGLASS FERRY
JOHN DOUGLASS FERRY
Pages 86-111
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Photograph courtesy University of Wisconsin-Madison.
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His work was always marked by a persistent, orderly, and detailed investigation of unsolved areas: actively identifying them, developing experimental tools to investigate them, interpreting the results on phenomenological and molecular scales as appropriate, and, from this, identifying the most important areas to be pursued next. John left polymer science with an enormous legacy of understanding of both the linear viscoelastic properties of polymeric systems and the origins of these properties in their conformations and motional dynamics.
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at Stanford University began at a time when the concept of polymers as giant molecules was just being accepted. For his Ph.D., Ferry sought to determine whether polyisobutylene, then a laboratory curiosity, had a glass temperature.1 His research also included an investigation of the temperature dependence of the viscosity of poly-isobutylene.1 It was here that he first encountered the phenomenon of viscoelasticity that was to become the central tenet of his research.
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It was here, in 1941, that he invented his unique shear wave propagation apparatus, with which he took ad
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This fibrin film became the first safe and effective surgical replacement for the dural membrane, thus making brain surgery feasible for the first time; it was used extensively to treat head wounds in the later stages of the war. A biodegradable tubular form of fibrinogen, suitable as a blood vessel replacement or scaffold was also produced, but too late to be used during the war.
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Thus began an aspect of his work (30 percent of his papers) that is little known to the polymer community: fibrinogen and its conversion to fibrin by polymerization.4 His group at Wisconsin first proposed, in 1947, the detailed mechanism for this polymerization as a stepwise lateral dimerization of the rod-like fibrin monomer units, with partial lengthwise overlapping, to give double stranded fibrils with a structure resembling a two-layer brick wall.
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One important result of these studies came from his insightful connection of the previously determined mechanical properties of crosslinked fibrin with the probable positioning of ligated gamma chains in the assembled polymer. His reasoning was clearly set forth in a 1996 letter to one of us (M.W.M.)
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From page 93... ...
Changing the concentration in such solutions dramatically changes the time scales of chain motions, which is why this was useful even if only approximately correct.2 (It isn't even approximately correct for dilute solutions.) Ferry immediately employed the superposition principle as a practical tool by showing how the shift factor, aT, for solutions could be readily obtained from simple steady flow viscosity measurements.
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The response of individual polymers is described by a more detailed, molecularly based analysis based on fractional free volume, its temperature dependence, and Tg. Thus, the fractional free volume occupies a central position in trying to understand the molecular origins of the temperature dependence of viscoelastic response.
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Ferry immediately recognized that Rouse's theory provided the molecular level framework he had been searching for. This led to many seminal contributions, including the following: • Giving a molecular basis for both reduced variables and the explicit form observed for the relaxation spectrum's different time dependencies in the dispersion, plateau, and termination (or onset of steady flow-like behavior)
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The displacements were accounted for by differences in the polymer's effective bond length (determined independently by light scattering from dilute solutions) , the Rouse monomeric friction coefficient, the molecular weight between entanglements and the fractional free volume.2 • Definitive experiments that demonstrated the direct relationship between small molecule diffusion in a rubber matrix and the Rouse monomeric friction coefficient for the matrix chains.
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Two-network studies also enabled molecular interpretation of the time dependence of the effects of trapped entanglements in terms of the tube model as separate contributions of segmental motion within the tube diameter, whole chain diffusion along the tube, and tube rearrangement itself.2 In work carried out after publication of the third edition of Viscoelastic Properties of Polymers, Ferry and Fitzgerald initiated a series of studies on carbon-black-filled rubbers showing that in the linear viscoelastic range, black particles formed their own associative network. Its contribution to the behavior of rubbers was then examined by Ferry in novel experiments (e.g., measuring the small strain dynamic response before, during, and after the application of a 40
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From page 98... ...
that enabled very-high-precision viscoelasticity measurements for solution viscosities down to 0.02 poise at shearing frequencies up to approximately 10 kHz.2,7,8,10 This enabled Ferry's group to obtain, on an extensive scale, high-precision data for very dilute solutions of a wide variety of synthetic and biopolymers. These measurements were sufficiently precise and covered sufficiently broad frequency ranges to provide reliable extrapolations to obtain the infinite dilution properties required for quantitative tests of the elegant (isolated molecule)
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, and provides semiquantitative-to-quantitative predictions for comb structures and randomly branched chains as well.8-11 This new characterization potential led to extensive studies exploring the influence of molecular weight, molecular weight distribution, chain flexibility, side-group size, long-chain branching, solvent quality, and charge screening (polyelectrolytes) on the observed viscoelastic properties.
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He spent his first two years in that immediate area since his father was a civil and mining engineer specializing in dredge mining of placer deposits. Having seen the Yukon ice breakup, he was officially a sourdough.
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This fascination with language persisted throughout his life as his most extensive avocation. John entered Stanford University at age 16, after again being held back by his father for a year, and received his A.B.
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Former students and associates have many fond memories of times spent at the Ferry home with John and his charming and vivacious wife, Barbara, probably best known for her elegant sculptures. The playing of games, including treasure hunts and charades, was a particuar attraction.
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He officially retired in 1982 but continued research until 1988, after which he continued writing scientific and historical papers until 1998. He supervised more than 50 graduate students, and more than 30 postdoctoral and for
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He was honored with the Eli Lilly Award in Biological Chemistry of the American Chemical Society, the Bingham Medal of the Society of Rheology, the Kendall Award in Colloid Chemistry of the American Chemical Society, the High Polymer Physics Prize of the American Physical Society, the Colwyn Medal of the Institution of the Rubber Industry (London) , the Witco Award in Polymer Chemistry of the American Chemical Society, the Technical Award of the International Institute of Synthetic Rubber Producers and the Charles Goodyear Medal of the Rubber Division of the American Chemical Society.
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In any given generation there is an occasional person who through his intellect, imagination, and ability to communicate, makes an indelible and important contribution to knowledge in his field. John Ferry was one of those people.
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Differential dynamic shear moduli of various carbon black-filled rubbers subjected to large step shear strain. Rubber Chem.
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Method for measuring dynamic mechanical properties of viscoelastic liquids and gels: the gelation of polyvinyl chloride.
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Dynamic mechanical properties of polyisobutylene.
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Dynamic mechanical properties of polyvinyl acetate in shear in the glass transition temperature range.
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Dynamic viscoelastic properties of polystyrene in high-viscosity solvents: Extrapolation to infinite dilution and high-frequency behavior. Macromolecules 4:210-214.
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Arai. Differential dynamic shear moduli of carbon black-filled styrene-butadiene rubber subjected to large shear strain histories.
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