Light scattering from nonequilibrium concentration fluctuations in a polymer solution
We have performed light-scattering measurements in dilute and semidilute polymer solutions of polystyrene in toluene when subjected to stationary temperature gradients. Five solutions with concentrations below and one solution with a concentration above the overlap concentration were investigated. T...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2000 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/59341 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/59341 |
| Access Level: | acceso abierto |
| Palabra clave: | 536 Equilibrium steady-state Stationary heat-flux Thermal-equilibrium Liquid-mixtures Diffusion-coefficient Rayleigh-scattering Hydrodynamic radius Molecular-weights Osmotic-pressure Mass Diffusion Termodinámica 2213 Termodinámica |
| Sumario: | We have performed light-scattering measurements in dilute and semidilute polymer solutions of polystyrene in toluene when subjected to stationary temperature gradients. Five solutions with concentrations below and one solution with a concentration above the overlap concentration were investigated. The experiments confirm the presence of long-range nonequilibrium concentration fluctuations which 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. In addition, we demonstrate that the strength of the nonequilibrium concentration fluctuations, observed in the dilute and semidilute solution regime, agrees with theoretical values calculated from fluctuating hydrodynamics. Further theoretical and experimental work will be needed to understand nonequilibrium fluctuations in polymer solutions at higher concentrations. |
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