The Journal of Chemical Physics
December 1998
Volume 109, Issue 24, Pages 11043-11050 

PII: S0021-9606(98)51848-X 
©1998 American Institute of Physics. 

Long-ranged relaxations in poly(ethylene oxide) melts:
Evidence for network behavior

R. Walkenhorst, J. C. Selser, and G. Piet 
Department of Physics, University of Nevada, Las Vegas, Las Vegas, Nevada 89154-4002 

(Received 24 July 1998; accepted 21 September 1998) 

Abstract:
Two slow, long-ranged relaxations in melts of poly(ethylene oxide) (PEO) were studied using the noninvasive dynamic light-scattering technique of photon correlation spectroscopy (PCS). Measurements were made for two PEO samples, one with a molecular weight distinctly above the entanglement value and a second sample with a molecular weight distinctly below the entanglement value. Based on several lines of evidence, it is concluded that the faster of these relaxations, which can be identified with the "cluster" or "Fischer" mode observed earlier in other homopolymer melts, results from the gel-like behavior of a physical network formed by the polymer in the melt, while larger-scale rearrangements in the polymer network structure are responsible for the slower relaxation.

Article Outline:
1. Introduction and background
2. Experiment
3. Results and discussion
4. The faster ACF mode
5. The Slower ACF mode
6. Comment
7. Conclusions
Acknowledgements
References