Structure and dynamics of polyelectrolytes in viscous polyelectrolyte-surfactant complexes at the mesoscale

Rather dilute mixtures of oppositely charged polyelectrolyte and surfactant can form highly viscous solutions for an excess of polyelectrolyte charges present, with viscosities up to 4 orders of magnitude above the pure polyelectrolyte solution. These changes in macroscopic behavior should originate from changes in the mesoscopic properties. Therefore, the structure and dynamics of such mixtures, namely JR 400 and SDS (h- or d-SDS) have been investigated using small-angle neutron scattering (SANS) and neutron-spin echo (NSE), where contrast matching allows to selectively study the behavior of the polyelectrolyte in these complexes. This combination of SANS and NSE allows to obtain uniquely detailed information on the individual components of the complex, showing that the polyelectrolyte to a high extent conserves its local mobility even in these highly viscous complexes and the high viscosity arises from the overall connectivity, information that is relevant for future potential applications of such systems