In their book Surface Tension and Adsorption, R. Defay, I. Prigogine, and A. Bellemans define surface tension as a condensed phase phenomenon that originates from the attractive forces between the specimen constituent molecules. It results in the tendency of fluid surfaces to shrink into the minimum possible surface area. It provides very useful information about intermolecular forces and as such it is important for the general theory of liquids. The vast majority of available literature reports the surface tension of water, aqueous solutions, and molecular liquids above 10 °C. The purpose of this project was to design and test an apparatus for measuring surface tension at low temperatures (10 0C to -50 0C). The apparatus consists of a custom made stalagmometer, which is placed in a dewar that is cooled with cold nitrogen gas. The temperatures were measured at the stalagmometer point where the droplet is formed and in the stalagmometer reservoir. Isopropyl alcohol was the liquid used in this experiment due to its low freezing point. This experiment consisted of two parts. Initially, after designing the stalagmometer the effective radius needed to be determined so that surface tension could be found using the Tate equation at any temperature. Water was used in this first part to calibrate the instrument. Once the effective radius was determined, the surface tension of isopropyl alcohol was measured at temperatures ranging from 10 0C to -50 0C; a linear decrease with temperature was observed. Our experimental data obtained were combined into one graph with literature values obtained in the temperature range +10 °C to +80 °C. A very good linear regression with R2 = 0.9901 was obtained; the slope of this plot was found to be -0.0905 dyne cm-2 °C-1. Experiments with other mono-hydroxyl alcohols are in progress. Nada Alharoon, Alexander J. Hoffman, and Samuel Marx contributed to the initial experimentation.

Low-temperature surface tension of isopropanol

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.