Experimental Study of Thermodiffusion and Thermoelectricity in Charged Colloids

TL;DR

This study experimentally investigates thermodiffusion and thermoelectric effects in charged colloids, revealing how nanoparticle entropy transfer influences thermoelectric properties, with potential applications in liquid thermocells.

Contribution

It provides new experimental data on thermodiffusion and thermoelectricity in charged colloids, highlighting the nanoparticle entropy transfer's role in thermoelectric enhancement.

Findings

Thermophoresis and thermoelectric voltage are measured independently.

Nanoparticle entropy of transfer can reach 75 meV/K.

Results suggest potential for improving thermocell efficiency.

Abstract

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 molecules and electric forces proportional to the internal thermoelectric field. The resulting thermodiffusion of nanoparticles is observed through Forced Rayleigh scattering, 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 75 meV/K. Such a property may be used to improve the thermoelectric coefficients in liquid thermocells.