The measurement of dynamic surface tensions of solutions of slowly diffusing molecules by the maximum bubble pressure method

Dynamic Surface Tension Measurement with a Dynamic Wilhelmy Plate Technique

“…The diffusion coefficients for the short-time approximation were obtained according to the following procedure: Arbitrary diffusion coefficients were substituted into the model for the short-time approximation (Eq. [21]) until the predicted dynamic surface tension curve fits the initial decrease of the experimentally measured dynamic surface tension. The range of this initial decrease should not be over 1 or 2 dyn/cm.…”

“…The integration term in Eq. [21] is difficult to be integrated analytically and requires using a numerical technique.…”

“…The drop volume (17)(18)(19), maximum bubble pressure (21)(22)(23), oscillating jet (24), and dynamic capillary (25) have been developed and extensively used in dynamic surface tension studies. These techniques involve the surface expanding and/or the solution flow creating the new aqueous/air interface.…”

Surface tension of solutions of pure sodium dodecyl sulfate

“…Most other workers seem to ignore dynamic ST as a criterion of purity even when studying effective methods of purification for ST measurements. Thus Czichocki et al 4 emphasize multiple recrystallization until ST reaches a constant value though this is still below that obtained by many other workers. Rosen3 introduced the very simple and quite effective purification by passage through a short column of C18-covered silica but his ST and cmc results also are lower than could be anticipated.…”

“…Figure4. Typical measurement of the surface tension showing the acceptance criterion and the extrapolation to 1 s. 5.48 mM sodium dodecyl sulfate at 25 °C.…”