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On the Mechanism of Shear-Thinning in Viscous Oppositely Charged Polyelectrolyte Surfactant Complexes (PESCs)

Del Sorbo, Giuseppe Rosario; Prévost, Sylvain; Schneck, Emanuel; Gradzielski, Michael; Hoffmann, Ingo

FG Physikalische Chemie / Molekulare Materialwissenschaften

Semidilute mixtures of the cationically modified cellulose-based polyelectrolyte JR~400 and the anionic surfactant Sodium Dodecyl Sulfate (SDS) form highly viscous solutions if a slight excess of charges from the polyelectrolyte is present. The reason for this is the formation of mixed rodlike aggregates in which the surfactant cross-links several polyelectrolyte chains. The same solutions also show shear thinning behaviour. In this paper we use rheoSANS to investigate the structural evolution of the rodlike aggregates under steady shear and thereby elucidate the mechanism of shear thinning in these viscous oppositely charged polyelectrolyte surfactant complexes.
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