Article Dans Une Revue European Physical Journal E: Soft matter and biological physics Année : 2004

Physical properties of aqueous suspensions of goethite (α -FeOOH) nanorods: Part I: In the isotropic phase

D. Petermann
  • Fonction : Auteur
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P. Panine
  • Fonction : Auteur
I. Dozov
J.P. Jolivet
  • Fonction : Auteur

Résumé

Depending on volume fraction, aqueous suspensions of goethite ( α -FeOOH) nanorods form a liquid-crystalline nematic phase (above 8.5%) or an isotropic liquid phase (below 5.5%). In this article, we investigate by small-angle X-ray scattering, magneto-optics, and magnetometry the influence of a magnetic field on the isotropic phase. After a brief description of the synthesis and characterisation of the goethite nanorod suspensions, we show that the disordered phase becomes very anisotropic under a magnetic field that aligns the particles. Moreover, we observe that the nanorods align parallel to a small field (< 350 mT), but realign perpendicular to a large enough field (> 350 mT). This phenomenon is interpreted as due to the competition between the influence of the nanorod permanent magnetic moment and a negative anisotropy of magnetic susceptibility. Our interpretation is supported by the behaviour of the suspensions in an alternating magnetic field. Finally, we propose a model that explains all experimental observations in a consistent way.

Dates et versions

hal-04944548 , version 1 (13-02-2025)

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Citer

B.J. Lemaire, P. Davidson, J. Ferré, J.P. Jamet, D. Petermann, et al.. Physical properties of aqueous suspensions of goethite (α -FeOOH) nanorods: Part I: In the isotropic phase. European Physical Journal E: Soft matter and biological physics, 2004, 13 (3), pp.291-308. ⟨10.1140/epje/i2003-10078-6⟩. ⟨hal-04944548⟩
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