INFLUENCE OF PHASE ORIENTATION ON DYNAMIC INTERFACIAL-TENSION MEASURED BY DROP VOLUME TENSIOMETRY

In processes involving two liquid phases, such as enhanced oil recover y, one phase is often present in a drop form (drop phase) while the ot her is in continuous form (bulk phase). In the present paper, the effe ct of such phase orientation on dynamic interfacial tension between th e two phases formed by the partially miscible system composed of butan ol-l and water has been investigated by using the method of drop volum e tensiometry. With butanol-rich (butanol-l saturated by water) as the drop phase and water-rich (water saturated by butanol-l) as the bulk phase, the interfacial tension is 1.70 +/- 0.02 mN/m. The interfacial tension for water-rich as the drop phase is almost identical at 1.72 /- 0.03 mN/m. Addition of a surfactant, sodium dodecyl sulfate, to the system has been studied. When the surfactant is added to the drop pha se (either butanol-rich or water-rich), the magnitude of the decrease in interfacial tension is smaller than when surfactant is added to the bulk phase (water-rich or butanol-rich) or to bath phases. Under othe rwise identical conditions, when the water-rich acts as the drop phase , the apparent interfacial tension is higher than that when the butano l-rich acts as the drop phase.