Publication: Concentration fluctuations in a polymer solution under a temperature gradient
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1998-12-21
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American Physical Society
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Abstract
We have performed small-angle Rayleigh light-scattering measurements in polymer solutions under various externally applied temperature gradients. Our experiments confirm the existence of an enhancement of the concentration fluctuations. The nonequilibrium concentration fluctuations are proportional to (del T)(2)/k(4), where del T is the applied temperature gradient, and k is the wave number of the fluctuations. The measured strengths of the nonequilibrium fluctuations in the dilute and semidilute concentration regime agree with the strengths calculated from fluctuating hydrodynamics.
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© 1998 The American Physical Society. We thank S. C. Greer for helpful advice concerning the characterization of the polymer sample and W. Köhler for valuable information for the Soret coefficient. This research is supported by the National Science Foundation, Grant No. CHE-9805260. J. M. O. Z. was funded by the Spanish Department of Education during his postdoctoral stage at Maryland, where the work was done.
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