Magnetic manipulation of nanoparticles through porous membranes

COLL 112

Jason R Stephens, jrs1089@psu.edu, Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802
We present studies that quantitatively understand magnetic controlled motion of nanoparticles through porous membranes. Using a u-tube design, a concentrated solution of magnetic nanoparticles is placed in one compartment and allowed to cross a membrane as a result of diffusion or attraction to a permanent magnet. The rate of transport is measured by the change in absorbance of the receiving cell solution over time, and is a function of particle size, pore diameter and solvent. Particle diffusion rates (in the absence of a magnetic field) dramatically decrease as the size of the particle approaches the size of the pores in the membrane. Particles diffuse faster in aqueous solutions than in hexane, despite the higher viscosity of water. When magnetic fields are applied, the translocation rate increases. The combination of magnetic-induced motion and size selectivity is a stepping stone to applying magnetic separation methodologies for complex nanomaterials.