Viscoelastic behavior of aqueous solutions of a polyoxyethylene-nonionic-amphiphile surfactant

Phase behavior of the Pluronic P103/water system in the dilute and semi-dilute regimes

“…3 shows the sound velocity as a function of temperature and P103 concentration. This figure reveals that for all concentrations studied, the sound velocity follows the characteristic behavior of water at low temperatures (i.e., a positive temperature coefficient) and then it shifts gradually to that of pure liquid polyoxyethylene nonionic surfactants (i.e., a negative temperature coefficient) [40] in a certain temperature interval Fig. 3).…”

Friction force measurements relevant to de-inking by means of atomic force microscope

“…Rheological studies of C 12 E 6 show that the bulk viscosity for the 10 cmc solution is close to water [28]. According to the Stokes-Einstein equation for low volume fractions, the viscosity increases with 5% up to a volume fraction of 0.02.…”

“…Thus the local (and effective) viscosity could increase thereby influencing the friction force. Certainly it is possible to envisage a region close to the periphery where the local volume fraction is as high as 23% which would result in an increase in relative viscosity of more than 100% [28], possibly leading to the intermediate region in the Stribeck curve, thereby lowering the friction force significantly.…”

Excess density in oilfield water—crude oil dispersions

“…The observed η(X) dependence (filled circles) is much steeper than the viscosity trends for w/o emulsions with noninteracting drops [27] predicted by the hydrodynamic Stokes-Einstein expression η = η OIL (1 + 2.5X) and by its quadratic expansion η = η OIL (1 + 2.5X + 6X 2 ) (solid lines 1 and 2, respectively). The best fit to our data set (solid curve 3) was obtained by applying the Mooney expression for dispersions of interacting particles (water drops) [28,29],…”