The surface tension of oil typically ranges from 30 to 35 dynes/cm.
This relatively low surface tension compared to water (around 72 dynes/cm) is a key characteristic that distinguishes oils. This difference is significant because it impacts how oil interacts with other substances, particularly in applications like surfactant usage. Because of this inherent surface tension, oil-soluble fatty surfactants are often ineffective at significantly reducing the surface tension of oils. This makes the formulation of stable oil-based emulsions more challenging compared to water-based emulsions.
