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Coil-coil interactions in dilute solution for poly(a-methylstyrene) in sub-, , marginal, and good solvents were studied using static and dynamic light scattering. The behavior observed across the solvent quality range is well described by a semiempirical fit to the interchain parameter kOv versus the reduced radius X = S/RH using a recent theoretical treatment developed by Akcasu and co-workers.

An investigation of a sol-gel/melt transition: The poly(ethylene oxide)/methanol/LiClO 4 system Two slow, long-ranged relaxations in melts of poly͑ethylene oxide͒ ͑PEO͒ were studied using the noninvasive dynamic light-scattering technique of photon correlation spectroscopy ͑PCS͒. 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.

Viscometry results, in conjunction with earlier light scattering data, revealed anomalously large values of the parameters = MA2/[t)] and kJM for dilute solutions of high molecular weight polyethylene oxide) (PEO) in water at 30 °C. Taken together with unusually large values of p = Rq/Rh and X = S/Rh for this system, it is concluded that these results may be partly explained by PEO coil draining, but, as suggested in the light scattering study, unusually strong and long-ranged PEO coil-coil interactions in solution were also responsible.