%0 Journal Article
%A de Gans, B.-J.
%A Wiegand, S.
%A Luettmer-Strathmann, J.
%T Unusual Thermal Diffusion in Polymer Solutions
%J Physical review letters
%V 91
%@ 0031-9007
%C College Park, Md.
%I APS
%M PreJuSER-32997
%P 245501-4
%D 2003
%Z Record converted from VDB: 12.11.2012
%X Thermal diffusion forced Rayleigh scattering results on thermal diffusion of poly(ethylene oxide) (PEO) in ethanol/water mixtures are presented. In water-rich solvent mixtures, PEO is found to migrate towards regions of lower temperature. This is typical for polymer solutions and corresponds to a positive Soret coefficient of PEO. In solvent mixtures with low water content, however, the polymer is found to migrate towards higher temperatures, corresponding to a negative Soret coefficient of PEO in ethanol-rich solutions. To our knowledge, this is the first observed sign change of the Soret coefficient of a polymer in solution. We also present a simple lattice model for the polymer solvent system and calculate Soret coefficients with statistical mechanics methods. The calculated values agree qualitatively with the experimental results.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000187202000041
%R 10.1103/PhysRevLett.91.245501
%U https://juser.fz-juelich.de/record/32997