Apparatus with active material surface in contact with rheological fluid and method of enhancing performance thereof

An apparatus is provided having an active material forming a surface thereof in contact with a rheological fluid. The active material is controllable to vary a surface geometry thereof between a rough or nonsmooth surface geometry to increase drag, and achieve an increase in stress transmitted through the fluid, when a field is applied, while allowing a smooth surface geometry and an associated reduction in stress transmitted through the fluid when the field is removed. A method of enhancing performance of an apparatus that includes a rheological fluid is also provided.