Micromechanics of dipolar chains using optical tweezers

Here we present our initial study of the micromechanical properties of dipolar chains and columns in a magnetorheological (MR suspension. Using dual-trap optical tweezers, we an able to directly measure the deformation of the dipolar chains parallel and perpendicular to the applied magnetic field. We observe the held dependence of the mechanical properties such as resistance to deformation, chain reorganization, and rupturing of the chains. These forms of energy dissipation are important for understanding and tuning the yield stress and rheological behavior of an MR suspension.