Surface dilatational properties of mixed sodium dodecyl sulfate/dodecanol solutions

Wantke, K. D.; Fruhner, H.; Örtegren, Jonas

doi:10.1016/s0927-7757(03)00135-3

Cited by 58 publications

(81 citation statements)

References 34 publications

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“…The average value of the power-law index m was found to be 0.64 ± 0.04 with 95% confidence interval. Note also that the surface dilatational modulus of aqueous SDS [16] and CTAB [29,30,31] in air is small and less than 60 mN/m suggesting that the bubble surfaces are tangentially mobile. Thus, experimental results for microfoams with spherical bubbles and porosity ranging from 0.54 to 0.72 are consistent with the theoretical models assuming large porosity, non-spherical bubbles, and non-zero slip velocity [16,19] as well as experimental data for a train of large polyhedral bubbles [17].…”

Section: Dimensional Analysismentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams) made from different surfactants

Zhao

Pillai

Pilon

2009

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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This paper extends our previous study on microfoam rheology made from non-ionic (Tween 20) surfactants to ionic surfactants. Anionic (sodium dodecyl sulfate) and cationic (cetyl trimethylammonium bromide) surfactants were used to generate microfoams by stirring an aqueous surfactant solution at high speed in a baffled beaker. Pipe flow experiments were performed in cylindrical stainless steel pipe 1.5 mm in diameter under adiabatic and fully developed laminar flow conditions. The porosity φ, bubble size distribution, Sauter mean radius 32 r , surface tension σ, and pH are reported for each solution. The porosity varied between 0.54 and 0.72 while the Sauter mean radius ranged from 28 to 48 microns. Zero slip velocity was assumed to prevail at the foam-wall interface as previously observed and reported in the literature for stainless steel pipes. Volume equalized method was used to analyze the data obtained from pipe flow viscometer. In all cases, microfoams behave as a shear thinning fluid. The results suggest that the dimensionless wall shear stress where τ w is the wall shear stress, a γ & is the shear rate, σ is the surface tension, µ l is the liquid velocity, and ε = 1/(1-φ) is the specific expansion ratio. The average value of the power-law index m was found to be 0.64 ± 0.04 with 95% confidence interval.

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Section: Dimensional Analysismentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams) made from different surfactants

Zhao

Pillai

Pilon

2009

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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show abstract

“…Therefore, as the interfacial dilatation becomes faster, the surfactant molecules at the interface cannot exchange quickly to the bulk, and fluctuation of γ from the equilibrium value, and consequently, the magnitude of E * increases, as long as the difference between the time scale of these processes is not too large. For very fast dilatation, however, the surfactant molecules have no time to exchange and the elasticity becomes independent of the oscillation frequency [20,21]. When an air-liquid interface undergoes sinusoidal deformation, a phase shift, φ, occurs between the area and surface tension curves.…”

Section: Interfacial Dilatational Rheologymentioning

confidence: 99%

Interfacial properties and foam stability effect of novel gemini-type surfactants in aqueous solutions

Acharya

Gutiérrez

Aramaki

et al. 2005

Journal of Colloid and Interface Science

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“…Because the relaxation dynamics of molecules adsorbed at fluid/fluid interfaces (diffusion exchange, surface rearrangement, etc.) occur over broad time scales, it is desirable to extend the experimentally accessible time scale into the high frequency range to explore faster relaxation modes [17][18][19][20]. Unfortunately, viscous forces generated from the motion of the oscillating drop invalidate the static Young-Laplace equation.…”

Section: Introductionmentioning

confidence: 99%