Polymer structure and the compensation effect of the diffusion pre-exponential factor and activation energy of a permeating solute

• Type: Article in International Scientific Journal
• Date: 2007

Authors

Zheng, JM (Author) Other; Qiu, J (Author) Other; Luis Madeira (Author) FEUP; Adélio Mendes (Author) FEUP

Journal

Title: Journal of Physical Chemistry B

Vol. 111

Pages: 2828-2835

ISSN: 1520-6106

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 8 Citations

ISI Web of Science

Scopus - 9 Citations

Scientific classification

FOS: Engineering and technology

CORDIS: Technological sciences > Engineering > Chemical engineering

Other information

Authenticus ID: P-004-B4T

DOI: 10.1021/jp067661o

Abstract (EN): In the present work, the relation between the pre-exponential factor and the apparent activation energy of diffusion, ln D-0 = alpha + beta E-D, so-called compensation effect, is re-examined and critically discussed for diffusion of gases in rubbery and glassy polymers. In principle, the above equation could be derived from the enthalpy-entropy compensation in the framework of the transition state theory. However, one should consider the influence of the jump length term contained in the pre-exponential factor, which may be affected by permeating species and polymer properties. We found that parameter alpha depends on penetrant size and polymer properties, such as local chain mobility and free volume. This can be interpreted by the fact that the jump length is affected by both penetrant and polymer properties. Finally, methods for estimating the jump length are discussed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8