The Potential Energy of a Pair of Polystyrene Spheres in Alternating Electric Fields

Abstract

The drastic change in the viscosity of electrorheological (ER) fluids when an external electric field is applied has intrigued scientists from many different fields including engineering, chemistry, and physics for over half a century. It has been generally understood that the microscopic attractive forces between induced dipole moments of the suspended particles have important effects on macroscopic fluid properties. Great effort has been given recently to maximizing the strength of the attractive forces between the particles in ER fluids to achieve practical fluids, and important progress has been made. Many questions, however, need to be investigated further. For example, it has been known that the addition of a small amount of water, that is, the addition of mobile charge carriers to an ER fluid, increases the ER effect, although the exact role that the mobile charges play in strengthening the induced dipole moments of the suspended particles is still not very well understood.1 It has also been shown in recent work on the stress response of ER fluids to transient electric fields that the relaxation process of an ER fluid is more complicated than just a simple fluid-particle dielectric mismatch model, and the surface conductivity of impurities adsorbed on particle surfaces seems to be a contributing factor.2 KeywordsColloidal ParticleApplied Electric FieldMobile ChargePolystyrene SphereUniform Electric FieldThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.