Dielectric dispersion in solutions of flexible polymers

doi:10.1515/ci-2021-0125

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Dielectric dispersion in solutions of flexible polymers

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Aus der Zeitschrift Chemistry International Band 43 Heft 1

W. H. Stockmayer

Pure and Applied Chemistry, 1967

Vol. 15, No 3-4, pp. 539-554

https://doi.org/10.1351/pac196715030539

This 1967 paper is part of PAC60 virtual collection assembled for the Diamond Jubilee of IUPAC scientific journal. The set of articles presented in this collection is a vivid glimpse of the rich variety of topics covered by the journal over the 60 years of its existence. https://cloud.newsletter.degruyter.com/60yearsPAC

Comments by Randal W Richards

This was an invited lecture at the IUPAC International Symposium on Macromolecular Chemistry in Tokyo in 1966.* Walter Stockmayer was one of the early pioneers in the chemical physics of polymer [1]. Over a long life, (he died at age 90 in 2004) he contributed to many areas of polymer science. His main focus was on the configurational and conformational behaviour of polymers in dilute solution. In particular on the effects of excluded volume and whether the expansion factor had fifth or cubic power dependence on the molecular weight.

In 1963 together with Michio Kurata, Stockmayer published an exhaustive analysis of the intrinsic viscosities of polymer molecules [2]. The paper reviewed here is an additional insight into the influence of conformation and excluded volume on the dielectric relaxation of polar polymers when subjected to a steady alternating field. Similar to the earlier viscosity publication, this paper does not put forward new theories but gathers together the ideas and explanations current at the time and applies them to experimental data with a view to determining the optimal theories.

The springboard is the observation that the mean square dipole moment of a polymer differs from the sum of the square of the individual bond dipole moments in a manner dependent on chain configuration and conformational statistics. Two types of polymer are considered; ones where dipoles are parallel to the chain direction, e.g. polyethylene oxide, and those where the dipole is rigidly attached perpendicularly to the chain direction. For the former case the mean square dipole moment is influenced by excluded volume effects to the same extent as the mean square end-to-end distance of the molecule. For the latter type of polymers, there is no correlation between the vector sum of the dipole moment components and the displacement vector, consequently excluded volume effects are absent.

Experimental data for low molecular weight polypropylene oxide are discussed in terms of the Rouse [3] – Zimm [4] bead – spring model and the free-draining description of viscosity by Bueche [5]. The comment is made that changes in the relaxation spectrum for high molecular weight polymers are due to entanglement effects, foreshadowing the development of reptation theories of de Gennes [6] as well as Doi and Edwards [7] some 15 to 20 years later. Perpendicularly attached dipoles are discussed in much less detail and in a rather more speculative manner, perhaps because excluded volume has no influence on the properties.

Walter Stockmayer was an extremely pleasant and affable person, a talented pianist and even in his 70s could walk further and longer than younger colleagues from my own personal experience. Other contributors to this Symposium were equally well known in contributing to polymer science. Clement Bamford had made major contributions to the kinetics of polymerisation; Frank Bovey was an early user of NMR to polymers and with Stockmayer a founding editor of Macromolecules; Charles Sadron set up and was first director of the Centre de Recherche sur les Macromolecules in Strasbourg, France; Maurice Huggins developed the thermodynamics of polymer solutions at the same time as, but independent of, Paul Flory; Otto Wichterle later pioneered soft contact lenses. A gallery of leading contributors to polymer science at that time.

Additional papers based on lectures presented at the International Symposium on Macromolecular Chemistry, Tokyo and Kyoto, Japan, 28 Sep–4 Oct 1966, are published in the same PAC issue (1967, Vol 15, Issue 3-4); http://publications.iupac.org/pac/conferences/TokyoandKyoto_1966-09-28f/index.html

References

1. W. H. Stockmayer and B. H. Zimm, When Polymer Science Looked Easy, Ann Rev Phys Chem 35:1, (1984); https://doi.org/10.1146/annurev.pc.35.100184.00024510.1146/annurev.pc.35.100184.000245Suche in Google Scholar PubMed

2. M. Kurata and W. H. Stockmayer Fortschr. Hochpolym. Forsch 3, 196, (1963)10.1007/BFb0050490Suche in Google Scholar

3. P. E. Rouse Jr J Chem Phys 21, 1272, (1953)10.1063/1.1699180Suche in Google Scholar

4. B. H. Zimm J Chem Phys 24, 269, (1956)10.1063/1.1742462Suche in Google Scholar

5. F. Bueche J Chem Phys 20, 1959, (1952)10.1063/1.1700349Suche in Google Scholar

6. P. G. de Gennes, Scaling Concepts in Polymer Physics, Cornell University Press 1979Suche in Google Scholar

7. M. Doi and S. F. Edwards, The Theory of Polymer Dynamics, Oxford University Press 1986Suche in Google Scholar

Online erschienen: 2021-01-22

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