Static and Dynamic Perturbations of Droplet Microemulsion by Confinement and Adsorption of Polymer

ABSTRACTThe effects induced on the structure and dynamics of dilute microemulsion droplets by the confinement of polymer chains inside the droplets and by the adsorption of polymer on the surfactant shells from the outer continous phase were studied. The local structure changes were observed by small angle neutron scattering (SANS). The curvature fluctuations and the size distribution of the droplets increase for both chains inside and outside by different possible mechanisms, an induced size polydispersity minimizing osmotic stresses in the first case, a lowering of the film rigidity in the second one. Neutron spin echo techniques (NSE) were also used to probe the shape fluctuations of the same droplets with and without polymer. A sharp characteristic peak due to the contribution of the 1=2 mode is exhibited by the spectrum of relaxation times as a function of wavevector q. The height of this peak is decreased with the addition of polymer. i.e. the fluctuation of the 1=2 modes are dampened with the addition of polymer. The effect on the elastic coefficient K of the surfactant layer will be discussed below.