Effect of polymer on the elasticity of surfactant membranes: a light scattering study.

L (0 to 0.4 mM), was incorporated into the solvent of sponge phases ofthe sodium dodecyl sulfate (SDS)-hexanol-brine system. PEG adsorbs into the SDS membranes. The correlationfunctions of the polymer-doped sponge phases displayed a stretched-exponential decay, appropriately describedby the Zilman-Granek (Z-G) theory for fluctuating membranes. The dynamics of the surfactant bilayers wasslowed down by the addition of the polymer: Increasing PEG concentrations increase the DLS relaxation times.FromtheZ-Gmodelweextractedthemembrane-bendingelasticmodulus,asafunctionofpolymerconcentration,