EFFECTS OF SODIUM DODECYL-SULFATE ON INTE RFACIAL-TENSION BETWEEN THE2 PHASES OF A PARTIALLY MISCIBLE SYSTEM CONSISTING OF BUTANOL-1 AND WATER

Interfacial tension between the two phases formed by the partially mis cible system composed of butanol-l and water has been investigated. Us ing the method of drop volume tensiometry, the effect of a surface-act ive agent, sodium dodecyl sulfate, on interfacial tension was investig ated. Addition of surfactant to the butanol-rich phase, which forms th e droplet, has been found to bring about a decrease in interfacial ten sion the magnitude of which was influenced by the time of contact. Whe n the surfactant was added to the aqueous (bulk) phase, the decrease i n interfacial tension was greater and it was equal to that observed wh en the surfactant was added to both phases. It is concluded that the o rientation of phases in the instrument has an important effect on the apparent interfacial tension observed.