Paul J. Flory

Paul J. Flory

Paul J. Flory,1910年6月19日出生,1985年9月9日逝世,伊利諾州斯特靈人,物理化學博士,著有《高分子化學原理》、《長鏈分子的統計力學》等。 Flory在高分子物理化學方面的貢獻,幾乎遍及各個領域。他是實驗家又是理論家,是高分子科學理論的主要開拓者和奠基人之一。由於他在“大分子物理化學實驗和理論兩方面做出了根本性的貢獻”而榮獲1974年度諾貝爾化學獎。 1985年Flory因心力衰竭而病逝,享年75歲。

人物經歷

Paul J. Flory1931年畢業於印第安納州Manchester學院化工系,1934年在俄亥俄州州立大學獲物理化學博士學位,後任職於杜邦公司,進行高分子基礎理論研究。1948年在康奈爾大學任教授。1957年任梅隆科學研究所執行所長。1961年任史丹福大學化學系教授,1975年退休。1953年當選為美國科學院院士。

Flory曾於1978和1979年兩度訪華。作為美方代表團團長,他參加了1979年在北京召開的“中美雙邊高分子化學及物理學討論會”,這是在我國首次召開的國際化學學術會議,Flory在會上作了“剛性鏈高分子的向列型液晶序理論”的報告,交流了最新成果,增進了兩國科學界的友誼與合作。

科研成就

Flory在半個多世紀裡的研究範圍廣泛、碩果纍纍。其中主要有:

① 縮聚反應過程中的相對分子質量分布理論;

② 自由基聚合反應的鏈轉移理論;

③ 體型縮聚反應的凝膠化理論;

④ 橡膠彈性理論;

⑤ 高分子溶液熱力學理論;

⑥ 溶液或熔體黏度與分子結構關係;

⑦ 非晶態聚合物本體構象概念;

⑧ 半結晶高聚物的分子形態、液晶高聚物理論等。

成果評價

這些成果每一項都包括一個廣大的領域。例如在高分子溶液的研究方面,20世紀40年代初提出的Flory-Huggins理論揭示了高分子溶液與理想溶液存在巨大偏差的實質,至今仍是高分子科學的里程碑之一。該理論是用於濃溶液體系,對液-液平衡、熔點降低、彈性體溶脹等的處理都獲得了滿意的結果。Flory在40年代後期開始研究排斥體積效應,提出Θ溫度的概念,明確了聚合物分子與溶劑分子間的相互作用、無擾鏈分子尺寸、以及稀溶液黏度等之間的相互關係。50年代提出Flory-Krigbaum稀溶液理論是該領域的代表性成果。60年代他利用溶液狀態方程處理溶劑、聚合物和溶液,推導出混合體積變化、混合熱以及由他提出的“作用參數”與濃度的關係,將高分子溶液理論又推進一步。由他建立的溶液理論不僅適用於高分子溶液,用於處理溶液體系同樣獲得成功。可以這樣說,在高分子物理化學中幾乎沒有未被Flory研究過的領域,在半個多世紀中他共發表論文300餘篇。

Flory曾出版過兩本著名的學術專著《高分子化學原理》和《鏈分子的統計力學》,其中前一本在美國再版達10次之多,被譽為高分子科學的“聖經”,使高分子科學工作者和學生的必讀書目。人們常常將Flory視為高分子科學的奠基者和開拓者,他本人則說,如果要他再從頭乾一遍的話,它仍然選擇高分子,因為“高分子更偉大的發現還在後頭”。

人物自述

I was born on 19 June, 1910, in Sterling, Illinois, of Huguenot-German parentage, mine being the sixth generation native to America. My father was Ezra Flory, a clergyman-educator; my mother, nee Martha Brumbaugh, had been a schoolteacher. Both were descended from generations of farmers in the New World. They were the first of their families of record to have attended college.

My interest in science, and in chemistry in particular, was kindled by a remarkable teacher, Carl W. Holl, Professor of Chemistry at Manchester College, a liberal arts college in Indiana, where I graduated in 1931. With his encouragement, I entered the Graduate School of The Ohio State University where my interests turned to physical chemistry. Research for my dissertation was in the field of photochemistry and spectroscopy. It was carried out under the guidance of the late Professor Herrick L. Johnston whose boundless zeal for scientific research made a lasting impression on his students.

Upon completion of my Ph.D. in 1934, I joined the Central Research Department of the DuPont Company. There it was my good fortune to be assigned to the small group headed by Dr. Wallace H. Carothers, inventor of nylon and neoprene, and a scientist of extraordinary breadth and originality. It was through the association with him that I first became interested in exploration of the fundamentals of polymerization and polymeric substances. His conviction that polymers are valid objects of scientific inquiry proved contagious. The time was propitious, for the hypothesis that polymers are in fact covalently linked macromolecules had been established by the works of Staudinger and of Carothers only a few years earlier.

A year after the untimely death of Carothers, in 1937, I joined the Basic Science Research Laboratory of the University of Cincinnati for a period of two years. With the outbreak of World War II and the urgency of research and development on synthetic rubber, supply of which was imperiled, I returned to industry, first at the Esso (now Exxon) Laboratories of the Standard Oil Development Company (1940-43) and later at the Research Laboratory of the Goodyear Tire and Rubber Company (1943-48). Provision of opportunities for continuation of basic research by these two industrial laboratories to the limit that the severe pressures of the times would allow, and their liberal policies on publication, permitted continuation of the beginnings of a scientific career which might otherwise have been stifled by the exigencies of those difficult years.

In the Spring of 1948 it was my privilege to hold the George Fisher Baker Non-Resident Lectureship in Chemistry at Cornell University. The invitation on behalf of the Department of Chemistry had been tendered by the late Professor Peter J. W. Debye, then Chairman of that Department. The experience of this lectureship and the stimulating asociations with the Cornell faculty led me to accept, without hesitation, their offer of a professorship commencing in the Autumn of 1948. There followed a most productive and satisfying period of research and teaching "Principles of Polymer Chemistry," published by the Cornell University Press in 1953, was an outgrowth of the Baker Lectures.

It was during the Baker Lectureship that I perceived a way to treat the effect of excluded volume on the configuration of polymer chains. I had long suspected that the effect would be non-asymptotic with the length of the chain; that is, that the perturbation of the configuration by the exclusion of one segment of the chain from the space occupied by another would increase without limit as the chain is lengthened. The treatment of the effect by resort to a relatively simple "smoothed density" model confirmed this expectation and provided an expression relating the perturbation of the configuration to the chain length and the effective volume of a chain segment. It became apparent that the physical properties of dilute solutions of macromolecules could not be properly treated and comprehended without taking account of the perturbation of the macromolecule by these intramolecular interactions. The hydrodynamic theories of dilute polymer solutions developed a year or two earlier by Kirkwood and by Debye were therefore reinterpreted in light of the excluded volume effect. Agreement with a broad range of experimental information on viscosities, diffusion coefficients and sedimentation velocities was demonstrated soon thereafter.

Out of these developments came the formulation of the hydrodynamic constant called theta, and the recognition of the Theta point at which excluded volume interactions are neutralized. Criteria for experimental identification of the Theta point are easily applied. Ideal behavior of polymers, natural and synthetic, under Theta conditions has subsequently received abundant confirmation in many laboratories. These findings are most gratifying. More importantly, they provide the essential basis for rational interpretation of physical measurements on dilute polymer solutions, and hence for the quantitative characterization of macromolecules.

In 1957 my family and I moved to Pittsburgh where I undertook to establish a broad program of basic research at the Mellon Institute. The opportunity to achieve this objective having been subsequently withdrawn, I accepted a professorship in the Department of Chemistry at Stanford University in 1961. In 1966, I was appointed to the J. G. Jackson - C. J. Wood Professorship in Chemistry at Stanford.

The change in situation upon moving to Stanford afforded the opportunity to recast my research efforts in new directions. Two areas have dominated the interests of my co-workers and myself since 1961. The one concerns the spatial configuration of chain molecules and the treatment of their configuration-dependent properties by rigorous mathematical methods; the other constitutes a new approach to an old subject, namely, the thermodynamics of solutions.

Our investigations in the former area have proceeded from foundations laid by Professor M. V. Volkenstein and his collaborators in the Soviet Union, and were supplemented by major contributions of the late Professor Kazuo Nagai in Japan. Theory and methods in their present state of development permit realistic, quantitative correlations of the properties of chain molecules with their chemical constitution and structure. They have been applied to a wide variety of macromolecules, both natural and synthetic, including polypeptides and polynucleotides in the former category. The success of these efforts has been due in no small measure to the outstanding students and research fellows who have collaborated with me at Stanford during the past thirteen years. A book entitled "Statistical Mechanics of Chain Molecules", published in 1969, summarizes the development of the theory and its applications up to that date.

Mrs. Flory, the former Emily Catherine Tabor, and I were married in 1936. We have three children: Susan, wife of Professor George S. Springer of the Department of Mechanical Engineering at the University of Michigan; Melinda, wife of Professor Donald E. Groom of the Department of Physics at the University of Utah; and Dr. Paul John Flory, Jr., currently a post-doctoral Research Associate at the Medical Nobel Institute in Stockholm. We have four grandchildren: Elizabeth Springer, Mary Springer, Susanna Groom and Jeremy Groom.

Paul J. Flory died in 1985.

Paul J. Flory was awarded the 1974 Nobel Prize in Chemistry for his fundamental achievements, both theoretical and experimental, in the physical chemistry of the macromolecules.

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