Randall Erb: Magnetic manipulation and assembly of multi-component particle suspensions

Magnetic manipulation and assembly of multi-component particle suspensions

    Randall Erb, Duke University, Center for Biologically Inspired Materials & Material Sciences (CBIMMS), USA

This talk will present previously unexplored concepts in magnetic manipulation including controlling the assembly of magnetic and nonmagnetic particles either in bulk fluid or near a substrate. Both uniform glass interfaces and substrates with magnetic microstructures are considered. The primary motivation is to discuss new strategies for implementing magnetic assembly systems that are capable of exquisitely controlling the positions and orientations of single-component as well as multi-component particle suspensions, including both magnetic and non-magnetic particles. Though the main focus is on controlling spherical particles, several demonstrations are provided of controlling anisotropically shaped particles, such as microrods and Janus colloids. Throughout this work, both conventional magnetophoresis and negative magnetophoresis techniques are employed, the latter relying on ferrofluid, i.e. a suspension of magnetic nanoparticles in a nonmagnetic carrier fluid, which provides a strong magnetic permeability in the surrounding fluid in order to manipulate effectively non-magnetic materials.