Self-diffusion of poly(ethylene oxide) in aqueous dextran solutions measured using FT-pulsed field gradient n.m.r. |
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Authors: | Wyn Brown Peter Stilbs |
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Affiliation: | Institute of Physical Chemistry, University of Uppsala, Box 532, S-751 21 Uppsala, Sweden |
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Abstract: | Transport in ternary polymer1, polymer2, solvent systems has been investigated using an n.m.r. spin-echo technique. The dependence of the self-diffusion coefficient of poly(ethylene oxide) polymers on the concentration and molecular size of dextran in aqueous solution has been measured. Monodisperse poly(ethylene oxide) fractions (, 2.8·105 and 1.2·106) and dextrans (, 1·105 and 5·105) have been employed over a range of concentration up to the miscibility limit in each system. It is found that when the molecular size of the diffusant is commensurate with or exceeds that of the matrix polymer, a relationship of the form: is applicable, where Cη] refers to the dextran component and is considered to describe the extent of coil overlap in concentrated solution. () is independent of the molecular size of the poly(ethylene oxide), at least in the range studied (Mw<300 000). |
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Keywords: | Self-diffusion n m r poly(ethylene oxide) dextran ternary system |
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