Elaboration of superparamagnetic nanorods using iron oxide nanoparticles and polymers

摘要

During the past years, we have investigated the complexation between metal oxide nanoparticles and oppositely charged polymers The attractive interactions between oppositely charged species are strong and in general the simple mixing of disperse solutions results in a precipitation, or in a phase separation Recently, we have developed means to control the electrostatically-driven attractions and at the same time to preserve the stability of the dispersions. Using this approach we have designed novel nanostructures, as those obtained with iron and cerium oxide nanoparticles. In this presentation, we give an account of the formation of colloidal and supracolloidal aggregates obtained by controlled co-assembly of 7 nm particles with copolymers. Nanostructured rods of length comprised between 1 and 100 um and diameter 500 nm were also disclosed. By application of an external magnetic field, the nanorods were found to reorient along with the magnetic field axis Preliminary micro-rheology experiments on test fluids have demonstrated the potential use of these nanostructured rods to determine the local viscosity of fluids.