(276e) Assembly of Paramagnetic Colloids Under Rotating Magnetic Fields: From Their Dynamic to Quasi-Equilibrium Morphologies

Colloids have been utilized in many different applications, such as drug delivery, catalytic processes, and liquid crystal displays. Due to their thermally-driven behaviors as accessible time scales, they have also been used as a model system for molecules to study phase behavior at the atomic level. Paramagnetic colloids are particles that acquire a dipole moment in the presence of magnetic fields. When a magnetic field is applied parallel to the particles’ distribution, the dipole moment will cause the formation of an interaction potential that is similar to that of Lennard-Jones systems, but with a longer range of attraction. By increasing the magnetic field strength one can increase the interactions between the particles and vice versa. This kind of tunability will allow for precise manipulation of particle interaction and as a result, manipulation of the particles’ assembly. We use these particles to generate two-dimensional sheets that show behaviors similar to that of liquid and crystalline systems. Focusing on both their dynamics and quasi-equilibrium states, we measure their energetics in the bulk and at the interface and show how these measurements change as we go from low to high interaction potentials.