Hostname: page-component-8448b6f56d-gtxcr Total loading time: 0 Render date: 2024-04-18T19:52:15.168Z Has data issue: false hasContentIssue false
  • English
  • Français

Diffusion in Polymer Alloy Melts

Published online by Cambridge University Press:  29 November 2013

Peter F. Green  and
Edward J. Kramer
Get access

Abstract

Diffusion in polymer alloys or blends can be used to extract information on the fundamentals of the dynamics of individual polymer chains in the melt and the thermodynamics of the interaction between unlike polymer species. The dynamics of individual chains are available from measurements of the tracer diffusion coefficients, D*, of the various species while the thermodynamics of interaction, represented by the Flory parameter, x, can be obtained from measurements of the mutual diffusion or interdiffusion coefficient, D. We will show that these quantities can be measured conveniently by forward recoil spectrometry (FRES), an ion beam analysis technique that can determine the concentration versus depth profile of polymers labeled with deuterium diffusing into unlabeled polymer matrices.

For high enough molecular weight of the matrix, the tracer diffusion coefficient of both species in the blend scale as D0N−2, where N is the number of monomer segments per diffusing chain; the constant D0, however, can differ by more than 104 for chemically different molecules diffusing in the same blend, suggesting that conventional concepts of chain dynamics in melts, such as monomer friction coefficients, need to be reexamined. The mutual diffusion coefficient is controlled by the faster species in the blend (the one with the larger D*N product) in agreement with what was found in metallic alloys (but in sharp disagreement with the “slow” theory of mutual diffusion which predicts that the slower species controls). Since the combinatorial (ideal) entropy of mixing of polymers is low, the thermodynamic driving force for diffusion is dominated by enthalpy and excess entropy of mixing (x) to a degree unprecedented for atomic or small molecule systems. This means that one can observe not only a thermodynamic “slowing down” of diffusion when x becomes positive as one nears the spinodal but also a large thermodynamic “speeding up” of diffusion when x is negative. Measurements of mutual diffusion turn out to be one of the most sensitive methods available for measuring x.

Type
Polymers
Information
MRS Bulletin , Volume 12 , Issue 8 , December 1987 , pp. 42 - 47
Copyright
Copyright © Materials Research Society 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Klein, J., Contemporary Physics, 20 (1979) p. 11.CrossRefGoogle Scholar
2.Voyutskii, S.S., Adhesion and Autohesion of High Polymers (Wiley-Interscience, New York, 1963).Google Scholar
3.deGennes, P.G., J. Chem. Phys. 72 (1980) p. 4756.CrossRefGoogle Scholar
4.Flory, P.J., Principles of Polymer Chemistry (Cornell University Press, Ithaca, NY, 1953).Google Scholar
5.Krause, S., Macromol, J.. Sci. Rev. Macromol. Chem. C7 (1972) p. 251.CrossRefGoogle Scholar
6.Flory, P.J., Statistical Mechanics of Chain Molecules (Wiley-Interscience, New York, 1969).CrossRefGoogle Scholar
7.Ferry, J.D., Viscoelasticity Properties of Polymers, 3rd ed. (Wiley, New York, 1980).Google Scholar
8.deGennes, P.G., J. Chem. Phys. 55 (1971) p. 572.CrossRefGoogle Scholar
9.deGennes, P.G., Scaling Concepts in Polymer Physics (Cornell University Press, Ithaca, NY, 1979).Google Scholar
10.Doi, M. and Edwards, S.F., J. Chem. Soc. Faraday II 8 (1980) p. 1789, 1809, 1818.Google Scholar
11.Graessley, W.W.Roy. Soc. Chem. Faraday Symposium No. 18 (1984) p. 1.Google Scholar
12.Graessley, W.W., Adv. in Polym. Sci. 47 (1982) p. 76.Google Scholar
13.Klein, J., Macromolecules 19 (1986) p. 105.CrossRefGoogle Scholar
14.Daoud, M. and deGennes, P.G., J. Polym. Sci. Polym. Phys. Ed. 17 (1979) p. 1971.CrossRefGoogle Scholar
15.Green, P.F., Mills, P.J., Palmstrom, C.J., Mayer, J.W. and Kramer, E.J., Phys. Rev. Lett. 53 (1984) p. 2145.CrossRefGoogle Scholar
16.Green, P.F. and Kramer, E.J., Macromolecules 19 (1986) p. 1108.CrossRefGoogle Scholar
17.Composto, R.J., Mayer, J.W., Kramer, E.J. and White, D.M., Phys. Rev. Lett. 57 (1986) p. 1312.CrossRefGoogle Scholar
18.Composto, R.J., PhD thesis, Cornell University, 1987.Google Scholar
19.Mills, P.J., Green, P.F., Palmstrom, C.J., Mayer, J.W. and Kramer, E.J., Appl. Phys. Lett. 45 (1984) p. 957.CrossRefGoogle Scholar
20.Green, P.F., Mills, P.J. and Kramer, E.J., Polymer 27, (1986) p. 1603.CrossRefGoogle Scholar
21.Doyle, B.L. and Peercy, P.S., Appl. Phys. Lett. 34 (1979) p. 811.CrossRefGoogle Scholar
22.Kramer, E.J., Green, P.F. and Palmstrom, P.J., Polymer 25 (1984) p. 473.CrossRefGoogle Scholar
23.Sillescu, H., Makromol. Chem. Rapid Commun. 5 (1984) p. 519.CrossRefGoogle Scholar
24.Brochard, F., Jouffroy, J. and Levinson, P., Macromoleciiles 16 (1983) p. 1638.CrossRefGoogle Scholar
25.Brochard, F. and deGennes, P.G., Europhysics Lett. 1 (1986) p. 221.CrossRefGoogle Scholar
26.Green, P.F., Palmstrom, P.J., Mayer, J.W. and Kramer, E.J., Macromoleciiles 18 (1985) p. 501.CrossRefGoogle Scholar
27.Darken, L., Trans. AIME 174 (1948) p. 184.Google Scholar
28.Composto, R.J., Kramer, E.J. and White, D.M., Nature (London) in press.Google Scholar
29.Jordan, E.A., Ball, R.C., Donald, A.M., Fetters, L.J., Jones, R.A.L. and Klein, J., Macromolecules (submitted).Google Scholar
30.Jones, R.A.L., Klein, J. and Donald, A.M., Nature 321 (1986) p. 161.CrossRefGoogle Scholar
31.Green, P.F. and Doyle, B.L., Phys. Rev. Lett. 57 (1986) p. 2407.CrossRefGoogle Scholar
32.Bates, F.S. and Wignall, G.D., Phys. Rev. Lett. 57 (1986) p. 2407.CrossRefGoogle Scholar
33.Yang, H., Stein, R.S., Han, C.C., Bauer, B.J. and Kramer, E.J., Polymer Commun. 27 (1986) p. 132.CrossRefGoogle Scholar