Structural, Thermodiffusive and Thermoelectric Properties of Maghemite Nanoparticles Dispersed in Ethylammonium Nitrate

Resumen

Ethylammonium nitrate (ionic liquid) based ferrofluids with citrate-coated nanoparticles and Na+ + counterions were synthesized for a wide range of nanoparticle (NP) volume fractions (F F ) of up to 16%. Detailed structural analyses on these fluids were performed using magneto-optical birefringence and small angle X-ray scattering (SAXS) methods. Furthermore, the thermophoretic and thermodiffusive properties (Soret coefficient ??T S T and diffusion coefficient ??m D m ) were explored by forced Rayleigh scattering experiments as a function of T and F F . They were compared to the thermoelectric potential (Seebeck coefficient, Se) properties induced in these fluids. The results were analyzed using a modified theoretical model on ??T S T and Se adapted from an existing model developed for dispersions in more standard polar media which allows the determination of the Eastman entropy of transfer (??^ NP S ^ NP ) and the effective charge (????????0 Z 0 e f f ) of the nanoparticles.