Anomalous change in interfacial tension induced by collapses of AOT microemulsions at heptane/water interface

Dynamic behavior of water-in-oil microemulsions at the oil/water interface was investigated using the quasi-elastic laser scattering method. We observed an anomalous rebound behavior of interfacial tension γ induced by collapses of microemulsions and adsorptions of AOT molecules at the interface. γ rapidly decreased and reached a minimum value (5.5 mN/m) at about 500 s after the preparation of the interface, and then increased gradually for about 2000 s to the equilibrium value (8.0 mN/m). We considered the mechanism of the rebound behavior in terms of transient change in interfacial thickness induced by the collapses of AOT microemulsions.