title: Investigation of the diffusion coefficient of polymers and micelles in aqueous solutions using the Soret effect in cw-laser thermal lens spectrometry.
abstract: The concentration gradient (Soret effect) induced in cw-laser thermal lens spectrometry subsequently to the formation of the thermal gradient (thermal lens effect) has been investigated in aqueous solutions of various macromolecular species including micelles, mixed micelles and polymers. It is shown that the build-up of the concentration gradient is much shorter than that in classical Soret experiments, reaching steady-state values in less than 1 min. The time evolution of the Soret signal has been used to derive mass-diffusion times from which mass-diffusion coefficients were calculated. Our data are in agreement with previous results obtained from quasi-elastic light scattering studies for the micellar solutions and calculated from a known molecular weight-dependent power law for polymer solutions.
authors.affiliation: Laboratoire des Sciences et Stratégies Analytiques, Université Claude Bernard-Lyon 1, 43 Boulevard du 11 Novembre 1918, Bâtiment CPE-308D, 69622 Villeurbanne Cedex, France. j.georges@cpe.fr
authors.forename: J
authors.initials: J
authors.lastname: Georges
mesh_terms: D004058:Diffusion; D007834:Lasers; D008823:Micelles; D011108:Polymers / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis / Q000379:methods; D013696:Temperature; D014867:Water
chemical_list: D008823:Micelles; D011108:Polymers; D012996:Solutions; D014867:Water