Bubble Entrapment: A Simple Method for Calculating the Interfacial Tension Between Two Immiscible Liquids

Interfacial chemistry has garnered much interest across the scientific community for over 100 years. From the Langmuir Isotherm to recent observations of curious chemistries, such as reaction acceleration and spontaneous formation of reactive oxygen species, interfacial phenomena have captivated chemists and physicists alike. Due to these important observations, the decades-long quest to introduce young scientists to interfacial chemistry has become even more important. Herein, we introduce undergraduate students to one of these interfacial properties, interfacial tension. We describe a simple and cost-effective method to experimentally determine the interfacial tension of two immiscible liquids with only a syringe, a vial, and a bubble. Using this hands-on activity, students were able to determine the interfacial tension of two systems, compare their results to literature values, and write a full lab report. This experiment not only provides students with practical insight into interfacial phenomena but also fosters a deeper appreciation for the relevance of interfacial chemistry in fundamental science and emerging research areas.