At the air-water interface, poly(dimethyl aminoethylmethacrylate) (poly(DMAEMA)) and sodium dodecyl sulphate (SDS) form multilayer structures at different surfactant concentrations at high and low pH. The use of different isotopic compositions, in particular a perdeuterated polymer in combination with both hydrogenated and perdeuterated surfactant, have allowed a complete characterization of the distribution of the polymer and surfactant across the multilayer structure.
At the silicon-water interface, a high charge density polyelectrolyte incorporating poly(ethylene oxide) side chains (poly(PEOyMEMA:METACx)) forms a multilayer structure at a bulk concentration of SDS that is below the CMC. The position of the characteristic Bragg peak in the reflectivity profile, suggests the presence of surface micelles. The use of multiple isotopic compositions allows us to propose a multilayer structure in which layers that are predominantly composed of SDS micelles and water alternate with layers that are predominantly polymer and water. The micellar layers do include some polymer, which suggests that a cooperative binding mechanism is responsible for the multilayer structure.