In-depth exploration of interfacial tension measurement techniques: an updated review

Measuring surface tension plays a critical role in various technological fields such as cosmetics, pharmaceuticals, biotechnology, medicine, and nanomaterials because it significantly affects material properties and process efficiency. In this review, we examined the five major categories of surface tension measurement methods, highlighting the strengths and weaknesses of each. The literature indicates that no single method can fully meet the diverse requirements for all surface tension measurements. Techniques based on the controlled deformation of liquid droplets, such as the spinning drop and micropipette methods, have demonstrated exceptional potential (0.001 − 0.1mN/m) for accurately assessing extremely low surface tensions. On the other hand, drop shape analysis techniques, such as the hanging drop and sessile drop, have notable advantages, including the use of relatively simple instruments, the ability to measure static and dynamic surface tensions in a non-contact manner, and their high-temperature performance with notable accuracy (0.01 − 0.1mN/m). Finally, methods based on capillary pressure measurement (bubble pressure method and maximum drop pressure method) are generally used in industrial sectors such as oil, gas and biology. These methods feature slightly higher uncertainties (0.1 − 0.3mN/m). However, they require highly advanced materials and a high level of technical expertise, which probably limits their wide-range use.