Interfacial Property
Speed at which a surfactant lowers the surface tension of a liquid as a new surface is formed. Chemical technicians measure dynamic surface tension to predict how well a dye bath will wet a fabric moving at high speeds through a padder. This measurement stops once the surface reaches a state of equilibrium.
Bubbling Method
Determination of this value involves measuring the pressure required to form a bubble at the tip of a capillary tube immersed in the liquid. If the bubbles are formed quickly, the measurement reflects the tension of a young surface where surfactant molecules have not yet fully migrated. This data is more relevant to industrial spraying than static measurements.
Wetting Speed
Fabric moving through a continuous dyeing range has only a fraction of a second to absorb the treatment liquor. If the surface tension does not drop fast enough, the liquid will fail to penetrate the fiber bundle, resulting in uneven color. High speed processing requires surfactants that can move rapidly to the newly created liquid-air interface.
Performance Limit
Action of a wetting agent is limited by the concentration of the chemical and the temperature of the bath. Increasing the concentration beyond the critical micelle point does not necessarily improve the speed of the surface tension reduction. The boundary of this effect is the chemical structure of the surfactant, which determines how fast the molecules can orient themselves at the surface.
Rapid tension reduction is necessary for high speed textile finishing.