Journal
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Volume 504, Issue -, Pages 414-425Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.colsurfa.2016.05.091
Keywords
Dynamic interfacial tension; Static interfacial tension; Critical micelle concentration; Adsorption; Diffusion coefficient
Categories
Ask authors/readers for more resources
Interfacial and surface tensions were measured at 25 degrees C for the toluene/water and air/water systems with dissolved nonionic surfactants Tween 20 or Tween 80. Dynamic surface/interfacial tensions were measured with the use of the drop volume method and were successfully fitted with the Hua and Rosen equation with characteristic times r. Static surface/interfacial tensions were determined from extrapolation of the dynamic data to t -> infinity on sigma or gamma versus t-(1/2) graphs. Obtained results were verified by measurements performed with the use of the Wilhelmy plate method. Critical micelle concentrations for considered surfactants were determined as well as maximum surface excess, minimum surface area per adsorbed molecule and diffusion coefficients were calculated for both fluid/fluid systems. The Frumkin adsorption isotherm was assumed and the Frumkin equation of state fits the experimental static surface/interfacial tensions well. Although the difference between HLB numbers of studied Tweens is small, it is sufficient to observe a different surface activity of surfactants at the air/water surface and toluene/water interface. Performed measurements and analysis give a deeper insight into the surface effects exerted by the nonionic surfactants such as Tween 20 and Tween 80, which in an agitated liquid/liquid dispersions are a source of the additional disruptive stresses generation. (C) 2016 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available