Magnetic clusters with controlled properties
Authors: Rodica Turcu, Izabell Crăciunescu
Keywords: magnetic nanoparticles, magnetic clusters, miniemulsification
Applications
Shape and size controlled magnetic clusters with high magnetic moments in external magnetic field represent an improved alternative to magnetic nanoparticles. They represent platforms for the synthesis of nanocomposites with the most diverse applications that depend on future functionalization.
Magnetic clusters are controlled aggregates of magnetic nanoparticles. The modification of surface properties by coating with different inorganic or organic polymeric layers, or with different molecules with specific functionalities offers the prospect of using magnetic clusters in a multitude of applications requiring the manipulation of functionalized particles with an external magnetic field, e.g. biotechnology, security, depollution, nanomedicine.
Innovative aspects
A new innovative product such as magnetic clusters with controlled physico-chemical properties has been realized by applying the miniemulsion method. The magnetic clusters have spherical shape, adjustable dimensions in the range 50-500 nm, superparamagnetic properties and high saturation magnetization values (50-70 emu/g). With high magnetic moment/particle, magnetic clusters can be magnetically separated from liquid media with very high efficiency.
Magnetic clusters are innovative nanomaterials that offer the possibility to combine different functionalities into a single entity by coating with different types of inorganic or organic layers.
Technology
Magnetic clusters with the desired shape and size are prepared by the miniemulsion method, using nanofluid based on hydrophobic magnetite nanoparticles as raw material.
The preparation method of magnetic clusters involves ultrasonication of a mixture of two liquid media, one aqueous containing a surfactant and one organic solvent-based containing magnetite nanoparticles stabilized with oleic acid. The resulting clusters exhibit high colloidal stability in aqueous medium and adjustable sizes in the range 50-500 nm, which are determined by electron microscopy.
Advantages
- Controlled structural, morphological (dimensions in the range 50-500 nm) and magnetic properties from the synthesis parameters (with deviations of max 10%)
- Superparamagnetic properties and high magnetic moment/particle
- Magnetic clusters can be obtained reproducibly at large scale
- Magnetic separation from liquid media can be done rapidly with very high efficiency
- Modification of the surface properties of magnetic clusters can be done by coating with different molecular layers to meet the requirements for multiple applications in: biotechnology, security, depollution, nanomedicine