Interfacial and bulk assembly of ellipsoidal microparticles under the influences of external electric fields

This talk will present recent work using Mirau Interferometry to accurately map the interfacial deformation around polymer microellipsoids pinned to an air-water interface under various external fields. We first explore how these particles align in bulk solution under different solution and electric field conditions to inform a set of design parameters when working at the interface. Measurements of particle dynamics in bulk were performed in order evaluate the torque on an ellipsoid due to a uniform AC electric field. At two-dimensional water-air interfaces, phase-shift Mirau interferometry is used to monitor the change in contact line undulations surrounding an ellipsoid at an air-water interface due to an electric field. By measuring the location of the three-phase contact line, we can determine the contact angle of pinned particles as a function of aspect ratio, hydrophilicity, solution conditions, and electric field characteristics. In doing so, an improved understanding of the forces acting on a particle at the interface as well as how applied electric fields can manipulate the pinning and ultimate assembly of such particles is achieved.