Measurement of interfacial tension by automated video techniques

Abstract

This report describes a simple automated system for measuring interfacial tension using the pendant or sessile drop method. The size and shape of a transparent or opaque drop of one fluid immersed in a second, transparent, fluid is recorded with a CCD video camera and digitized and stored by a computer-controlled system. Custom software determines various droplet shape factors and computes the interfacial tension. A limited number of video frames can be stored on disc, or longer runs can be stored on video tape for later digitization. Alternately, only the shape factor and interfacial tension data are stored to reduce demands on the storage medium.