In this paper we report the observation of the formation of surface micelles, or hemimicelles, using ellipsometry. SDS is adsorbed onto a platinum electrode from solutions with concentrations below the critical micelle concentration (cmc). Formation of the surface micelles is initiated by applying a potential at the electrode, inducing local concentrations above the critical hemimicelle concentration (chmc) near the electrode surface. The thickness of the adsorbed layer, as measured by ellipsometry, based on a film refractive index of 1.44, at low potentials is 10–15 Å, which corresponds to the extended dimension of the SDS molecule. At higher potentials, transitions to films 2–3 times the initial film thickness are observed.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces