Rheological studies of aqueous alkylpolyglucoside surfactant solutions

Alkylpolyglucosides (C(Y)G(X)) are industrial products of mixtures consisti ng of a hydrocarbon chain with Y carbon atoms linked to X sugar residues. B ased on detailed analytical investigation of technical grade alkylpolygluco sides (C(8-10)G(X), C(12-14)G(X) and C(8-16)G(X))/ water systems using high -performance liquid chromatography in combination with a special kind of ma ss spectroscopy their rheological behaviour is discussed and compared to th e rheological behaviour of pure alkyl monoglycosides (C(8)G(1) and C(10)G(1 )) in water. The rheological properties that exhibit a dependence on the al kyl chain length, Y, and the degree of polymerisation, X, are investigated by rotation and oscillation experiments over an extended concentration rang e. The Maxwell model fits the frequency dependence of the dynamic functions fairly well. The viscosity shows an Arrhenius-like dependence on temperatu re. A comparison is drawn between the monoglucosides and the polyglucosides , which shows that the rheological properties are more sensitive to the a c hange in chain length than in the degree of polymerisation. Phase transitio ns, especially liquid-crystalline to isotropic solutions, phase split into two coexisting liquid phases, and could be followed using visual observatio n and rheology. Depending on the difference in the rheological properties o f the corresponding phases, viscoelastic measurements showed these transiti ons dearly. Additionally, the changes in viscosities were measured after ad dition of a second surfactant.