Abstract
Poly(ethylene glycol) (PEG) with a molecular weight of about 4600 in semidilute solutions with D2O as solvent has been studied by small-angle x-ray scattering in a broad temperature range from 10 to 100°C at concentrations from 1wt% to 20wt%. The scattering from the PEG solutions can be very well described by a random phase approximation (RPA) type expression. The forward scattering of the chains is analysed by two different approaches: In terms of temperature dependent virial coefficients and in terms of the recently derived Flory-Huggins theory for polymers solutions with a temperature dependent chi parameter. The virial approach gives a theta temperature of 100°C. A satisfactory fit by the virial approach requires only a second and a forth order virial coefficient. In the Flory-Huggins theory a correction for the finite polymer volume fractions results in a lower value of the theta temperature of 86°C. The chi parameter varies from 0.32 at 10°C to 0.52 at 100°C. The analysis of the temperature dependence of chi shows that it is predominately due to entropic effects.
This paper is dedicated to Prof. W. Ruland on the occation of his 80th birthday
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© 2005 Springer-Verlag Berlin Heidelberg
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Pedersen, J.S., Sommer, C. (2005). Temperature dependence of the virial coefficients and the chi parameter in semi-dilute solutions of PEG. In: Stribeck, N., Smarsly, B. (eds) Scattering Methods and the Properties of Polymer Materials. Progress in Colloid and Polymer Science, vol 130. Springer, Berlin, Heidelberg. https://doi.org/10.1007/b107350
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DOI: https://doi.org/10.1007/b107350
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Online ISBN: 978-3-540-31510-0
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