Designing magnetic composite materials from aqueous magnetic fluids

José Alberto Galicia (1) , Olivier Sandre (1) , Fabrice Cousin (2) , Dihya Guemghar (1) , Christine Ménager (1) , Valérie Cabuil (1)

1 LI2C - Liquides Ioniques et Interfaces Chargées
2 LLB - UMR 12 - Laboratoire Léon Brillouin

In this paper, we report how to take advantage of the good knowledge of both the chemistry and the stability of an aqueous magnetic colloidal suspension to realize different magnetic composites. The osmotic pressure of the magnetic nanoparticles is set prior to the realization of the composite to a given value specially designed for the purpose of each hybrid material: magnetic particles in polymer networks, particles as probes for studying the structure of clay suspensions and shape modification of giant liposomes. At first, we show that the introduction of magnetic particles in polyacrylamide gels enhances their Young modulus and reduces their swelling by water. The particles cause both a mechanical and an osmotic effect. The latter is strongly dependant on the ionic strength and attributed to an attraction between particles and polymeric matrix. In the second part, we determine the microscopic structure of suspensions of laponite as a function of concentration, by combining SANS and magneto-optical experiments with the probes. This study requests conditions for including the magnetic particles as probes without disturbing the clay suspensions. The third part presents giant magnetoliposomes, which encapsulate magnetic nanoparticles. Shape transitions are obtained with either a magnetic field or an osmotic stress.

Domaines: Chimie; Matériaux

José Alberto Galicia, Olivier Sandre, Fabrice Cousin, Dihya Guemghar, Christine Ménager, et al.. Designing magnetic composite materials from aqueous magnetic fluids. Journal of Physics: Condensed Matter, 2003, 15 (15), pp.S1379-S1402. ⟨hal-01934989⟩