New Methodology to Determine Equilibrium Surfactant Adsorption Properties from Experimental Dynamic Surface Tension Data

Langmuir ◽  
2009 ◽  
Vol 25 (11) ◽  
pp. 6191-6202 ◽  
Author(s):  
Srinivas Nageswaran Moorkanikkara ◽  
Daniel Blankschtein
2004 ◽  
Author(s):  
Hans C. Mayer ◽  
Shelley L. Anna

Recent theoretical predictions indicate that a shift in surfactant transport mechanism from diffusion controlled to kinetically controlled occurs at highly curved interfaces where the length scale is on the same order as feature sizes in microfluidic devices. At present, experimental evidence of this shift in transport mechanism is lacking and this is due to the limitations on degree of interface curvature imposed by traditional methods of surface tension measurement. We show that the measurement of dynamic surface tension is possible at highly curved interfaces using a microfluidic tensiometer that utilizes glass micropipettes to control curvature dimension. Comparison of dynamic surface tension data from our microfluidic tensiometer with data obtained from traditional techniques will validate the theoretical arguments reported, and will improve understanding of two phase flows in microfluidic devices.


2004 ◽  
Vol 6 (7) ◽  
pp. 1592-1596 ◽  
Author(s):  
Ch. Frese ◽  
S. Ruppert ◽  
H. Schmidt-Lewerkühne ◽  
K. P. Wittern ◽  
R. Eggers ◽  
...  

1996 ◽  
Vol 10 (4) ◽  
pp. 395-405 ◽  
Author(s):  
R. Wüstneck ◽  
J. Krägel ◽  
R. Miller ◽  
V.B. Fainerman ◽  
P.J. Wilde ◽  
...  

2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Hernán Martinelli ◽  
Claudia Domínguez ◽  
Marcos Fernández Leyes ◽  
Sergio Moya ◽  
Hernán Ritacco

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.


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