ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Summary Quasielastic light scattering measurements and pulsed field gradient NMR measurements have been made on poly(ethylene oxide) fractions in semi-dilute solutions. Similar measurements have been made on polystyrene in chloroform and toluene. Through suitable choice of sampling times, the QELS experiments allowed analysis of the “fast” and “slow” modes of relaxation in terms of the corresponding diffusion coefficients and their relative amplitudes. Comparison of the slow mode with self-diffusion shows that the former is between one and two orders of magnitude slower than self-diffusion which contrasts with a number of recent reports. Furthermore, the proportion of fast to slow modes is highly sensitive to temperature and concentration. It is concluded that the slow mode must involve a concerted pseudogel motion sensitive to polymer-polymer friction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00262723
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