Interfacial Tension of Alkane + Water Systems

Abstract

Interfacial tension was measured for hexane + water, heptane + water, octane + water, nonane + water, decane + water, undecane + water, and dodecane + water, using the emergent drop experimental technique with a numerical method based on a fourth degree spline interpolation of the drop profile. The experimental equipment used to generate the drop consists of a cell with a stainless steel body and two Pyrex windows. The inner cell was previously filled with water. A surgical needle (at the bottom of the cell) was used to introduce the organic phase into the cell (forming the emergent drop). Water was used to keep the temperature constant inside the cell (between 10 °C and 60 °C). The cell was illuminated from the back using a fiber optic lamp and a diffuser. A video camera (with a 60 mm microlens and an extension ring) was located at the front window. The emergent drop image was captured and sent to the video recording system. The cell and the optical components were placed on an optical table with vibration isolation legs. A new correlation was found to predict interfacial tension (γ) as a function of temperature (t) and the number of carbon atoms (n) with a deviation of less than 0.05% from experimental values.