Time-resolved small-angle neutron scattering study of shear-thickening surfactant solutions after the cessation of flow

Shear effects in dilute solutions of gemini surfactant solutions are studie d by SANS in the shear-thickening regime. After the cessation of flow, the local anisotopy relaxes in about 10(2) s and we find evidence for a shear-i nduced change in the structure of the solutions that is stable for at least a few hours. The results can be understood if the shear-induced viscous ph ase is a loosely connected network of long-lived aggregates with typical si ze of 1 mu m. Counterions-mediated attraction between rodlike micelles coul d explain the formation of the aggregates and their long lifetime. The whol e picture is consistent with previous results obtained for the same system using different techniques.