C14EO8 adsorption characteristics studied by drop and bubble profile tensiometry

The adsorption characteristics of the non-ionic surfactant C14EO8 studied by drop and bubble profile tensiometry at the solution/air interface is best described by a model that considers molecular reorientation and compressibility at high surface coverage. The comparison of the adsorption equilibrium at a single drop surface with that at the surface of a bubble formed in a large solution reservoir allows determining the adsorbed amount at the solution surface. The adsorption isotherm data are used to quantitatively describe the adsorption kinetics as well as the dilational elasticity and viscosity over the entire concentration range up to the CMC. It is shown that dilational rheology data are most sensitive to the physical models while the equilibrium surface tensions are less sensitive and can be described adequately also by a Frumkin model.