What is Dynamic Surface Tension?
Many fluids and formulations contain surfactants, or other impurities that are surface active or time dependent. A surfactant is a chemical whose molecules have a hydrophobic segment and a hydrophilic segment. This partial solubility allows this molecule to migrate to and occupy the space at the gas/fluid interface. Surfactants greatly reduce the surface tension of solvents, water and water-based solutions, inks, fountain solutions, adhesives and other coating formulations. To reduce the surface tension, however, the surfactant molecules have to migrate to the interface, and this takes some finite amount of time. Given enough time, the formulation will eventually reach equilibrium (static) surface tension. This takes several seconds or even several minutes depending on the type of surfactant and the concentration. If you do not allow enough time for the solution to reach equilibrium you are then operating in the dynamic zone, and the critical measurement parameter is dynamic surface te
