By L.U.M. GmbH
Magnetic micro- and nanoparticles have increasingly wide applications in information technology, magnetic fluids, selective separation, and nanomedicine. Their susceptibility (responsiveness) and magnetization has to be analyzed during particle design, optimization of application and quality control of the production process. Determination of magnetophoretic velocity by optical STEP-Technology® as a tool to characterize assembled objects and determination of magnetic responsiveness can be applied to very different magnetic objects. Besides magnetophoretic velocity distributions under gravity, analytical centrifugation can be employed to quantify the magnetization and magnetic forces between magnetic particles using magnetic fields directed orthogonally to the centrifugal field. The recycling of waste materials is essential for society’s transition to a circular economy, and a novel recycling technology based on magnetic density separation is being developed by LUM instrument users. Nonmagnetic solid materials dispersed in a ferrofluid will levitate in external magnetic field, reaching specific floatation heights that depend mainly on the buoyant mass densities of the materials and the precise height dependence of the magnetic field strength. However, ferrofluids consist of colloidal dispersions of magnetic nanoparticles in a solvent, and in external magnetic field, there is the risk of rapid degradation of the ferrofluid. In LUM customers‘ research, they characterize the field-dependent colloidal stability of ferrofluids using X-ray-STEP-technology.
