Effect of Electrode Potential on the Drag Force on Gold and Polyvinyl Butyral Surfaces in a Flowing Aqueous Fluoride Solution

摘要

It is shown that positive electrical polarization reduces the drag force on gold- and polyvinyl butyral(PVB)-coated spheres immersed in a stream of aqueous sodium fluoride solution. This effect is relatedto a decrease in the interfacial viscosity of the solution at the positively polarized gold and PVBsurfaces, as obtained from quartz resonator measurements. The decrease in viscosity at a polymercoated electrode is larger than that at a gold electrode, which is consistent with drag forcemeasurements. The drag force reduction due to decreased interfacial viscosity at a polymer-coatedmetallic surface on application of an electrical potential widens the range of possible applications ofthis effect for active manipulation of wall-bounded liquid flows, given that the use of metal surfaces islimited by their risk of corrosion.