Thermoelectricity and thermodiffusion in charged colloids

B. T. Huang (1) , M. Roger (1) , M. Bonetti (1) , T. J. Salez (2, 1) , C. Wiertel-Gasquet (1) , Emeric Dubois (3) , R. Cabreira Gomes (3, 4) , G. Demouchy (3, 5) , G. Mériguet (3) , V. Peyre (3) , M. Kouyaté (3) , C. L. Filomeno (3, 4) , J. Depeyrot (4) , F. A. Tourinho (4) , R. Perzynski (3) , Sawako Nakamae (1)

1 SPEC - UMR3680 - Service de physique de l'état condensé
2 ENPC - École des Ponts ParisTech
3 PHENIX - PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX
4 Complex Fluids Group [Brasilia]
5 UCP - Université de Cergy Pontoise

The Seebeck and Soret coefficients of ionically stabilized suspension of maghemite nanoparticles in dimethyl sulfoxide are experimentally studied as a function of nanoparticle volume fraction. In the presence of a temperature gradient, the charged colloidal nanoparticles experience both thermal drift due to their interactions with the solvent and electric forces proportional to the internal thermoelectric field. The resulting thermodiffusion of nanoparticles is observed through forced Rayleigh scattering measurements, while the thermoelectric field is accessed through voltage measurements in a thermocell. Both techniques provide independent estimates of nanoparticle’s entropy of transfer as high as 82 meV K$_{−1}$. Such a property may be used to improve the thermoelectric coefficients in liquid thermocells.

Mots clés: Nanoparticles; Colloidal systems; Entropy; Thermoelectric effects; Suspensions

Domaines: Physique [physics]

B. T. Huang, M. Roger, M. Bonetti, T. J. Salez, C. Wiertel-Gasquet, et al.. Thermoelectricity and thermodiffusion in charged colloids. Journal of Chemical Physics, 2015, 143, pp.054902. ⟨10.1063/1.4927665⟩. ⟨cea-01367117⟩