Tensiometric

Tensiometric, relating to tensiometry, refers to the measurement of surface tension or interfacial tension using instruments called tensiometers. Surface tension is the cohesive force at the surface of a liquid, while interfacial tension is the force at the boundary between two immiscible liquids. Tensiometry provides quantitative data on how liquids interact with interfaces and how surface-active agents alter those interactions.

Common tensiometric methods include the Du Noüy ring method, which determines surface tension from the force required to detach a ring from the liquid surface; the Wilhelmy plate method, which measures the force on a plate partially immersed at an interface; the capillary rise method, based on the height to which a liquid ascends in a capillary; and drop-based methods such as pendant drop and sessile drop, which infer tension from drop shape via the Young-Laplace equation. Dynamic or time-resolved approaches, like dynamic surface tension measurements, capture changes during adsorption of surfactants or during rapid interfacial processes.

Tensiometry is used across chemistry, materials science, biology, and engineering. Applications include formulation and quality control of detergents, cosmetics, foods, and pharmaceuticals; polymer and coating science; emulsions and foams stability; and investigations of interfacial phenomena in surfactant systems, emulsions, and colloids. Results are influenced by temperature, cleanliness, liquid purity, and the presence of surface-active species, and they may depend on the measurement method and sample history.

See also: surface tension, interfacial tension, tensiometer, surface chemistry, colloid and interface science.