Dynamic Surface Tension and Adsorption Kinetics from Micellar Solutions on Planar Surfaces
A qualitative theory of the dynamic surface tension and adsorption kinetics from micellar surfactant solutions on a planar surface is developed for the kinetic-diffusive-controlled adsorption process obeying any adsorption kinetics on a planar surface and any micellization-demicellization kinetics in the bulk. The time-dependent adsorption and dynamic surface tension is obtained in an analytical form for short and long times. It is shown that the adsorption process and dynamic surface tension over a wide range of surfactant (monomer) concentrations is governed by: (I) the adsorption kinetics of monomers and micelles for short times (0 </= t </= tcr1), (II) the adsorption kinetics of monomers and micelles on a planar surface and the micellization-demicellization kinetics in the bulk, and the diffusion of monomers and micelles for intermediate times (tcr1 </= t </= tcr2), and (III) the diffusion of monomers and micelles for long times (t >/= tcr2). Formulas were derived to estimate the relaxation times tcr1, tcr2, and the parameters characterizing the adsorption process over a wide range of times. The existence of the (I), (II), and (III) regimes are justified by using the experimental data for the dynamic surface tension of a micellar Brij 58 solution.
Filippov
LK
Lehigh University, Bethlehem, Pennsylvania, 18015
Filippova
NL