Effect of SDS on the self-assembly behavior of the PEO-PPO-PEO triblock copolymer ([EO.sub.20])([PO.sub.70])([EO.sub.20])

Small-angle neutron scattering (SANS) and viscosity measurements are used to study the mixed micellar system comprising the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-based triblock copolymer ([EO.sub.20])([PO.sub.70])([EO.sub.20]) and the anionic surfactant sodium dodecyl sulfate (SDS). Copolymers with high PO/EO ratios have showed an increase in the stability of the gel phase, whereas copolymers with low PO/EO ratios have showed a deterioration of the same in the presence of SDS.