PROFILES AND AREAS OF INTERFACES IN THE DU NOÜY RING METHOD

Abstract

Profiles and areas of interfaces subjected to interfacial tension measurements by the du Noüy ring method, were calculated with the aid of a digital computer. The computations were based on a solution of a set of two simultaneous, first order, ordinary differential equations. Area corrections amounted to from 5 to 17% of the total area calculated on the assumption of planar contact. These corrections permit more precise evaluation of the molecular area of monolayers spread at such interfaces. Two interfaces, viz. benzene–water and hexane–water, were taken as examples. Profiles of curves around the rings were also determined experimentally by means of an electrical contact micromanipulator method. Theoretically computed and measured profiles show very good agreement.