Unsteady Wetting on a Rough Surface due to Electrically Altered Surface Tension

Measurements of unsteady wetting on a rough surface were made. Spreading was initiated by electrically altering the solid-liquid surface tension. The resultant time-dependent interface shape could be described by steady theory augmented with an ad hoc model which accounts for surface roughness. Flattening of the interface induced by pinning appears in the equations as "slip" which lowers the effective capillary number. Copyright 1999 Academic Press.