MEASUREMENT OF DYNAMIC SURFACE TENSION OF SURFACTANT SOLUTIONS WITH THE DROP VOLUME METHOD USING AN AUTOMATIC DROP DETECTOR

Abstract

The dynamic surface tension of TRITON X-100 surfactant solutions were measured with the drop volume method using a stalagmometer supplied with automatic drop counter. The apparatus constructed at the Physical Chemistry Institute consists of four stalagmometer units and a four-channeled electronic drop- and time-counter. The dynamic surface tension decreased with the dropping time because of a diffusion barrier of the surfactant molecules at low concentrations and because of the time necessary for the micelles to decompose into surfactant molecules at high concentrations.