This work is focused on the detailed experimental study of bubble adhesion on a hydrophobic solid surface. The frame rate 16000 fps was used in side view arrangement in order to capture in detail the three-phase contact line expansion and bubble shape changes. Experiments were done in pure water and in solutions of the anionic surfactant sodium dodecyl sulphate in low, medium and high concentrations. It was found out that the rupture of a liquid film is not symmetrical with respect to the vertical axis of the bubble symmetry. This asymmetry of TPC line formation leads to bubble surface oscillations and asymmetry in dynamic contact angles. These dynamic mechanisms are diminished with increasing surfactant concentration. The non-linearity of expansion velocity was also observed. In the case of high bubble surface mobility, the expansion velocity first decreases and after few milliseconds, the second velocity maximum emerges caused by kinetic energy dissipation. In surfactant solutions, the arising Marangoni stresses should be taken into account because the expansion velocity increases in the first moments of TPC line expansion. Existing models, such as hydrodynamic and molecular-kinetic, are not able to incorporate with bubble oscillations in pure liquids as well as the non-monotonic curve of expansion velocity profile in surfactant solutions.
REFERENCES(17)
1.
Basarova, P., Suchanova, H., Souskova, K., Vachova, T., 2017. Bubble adhesion on hydrophobic surfaces in solutions of pure and technical grade ionic surfactants. Colloid Surf. A 522, 485-493.
Fell, D., Auernhammer, G., Bonaccurso E., Liu, C., Sokuler, R., Butt H-J., 2011. Influence of surfactant concentration and background salt on forced dynamic wetting and dewetting. Langmuir 27, 2112–2117.
Fujasova-Zednikova, M.; Vobecka, L.; Vejrazka, J., 2010. Effect of solid material and surfactant presence on interactions of bubbles with horizontal solid surface. Can. J. Chem. Eng. 88, 473-481.
Malysa, K., Krasowska, M., Krzan, M., 2005. Influence of surface active substances on bubble motion and collision with various interfaces. Adv. Colloid Interface Sci. 114–115, 205–225.
Phan, C. M.; Nguyen, A. V.; Evans, G. M., 2003. Assessment of Hydrodynamic and Molecular-Kinetic Models Applied to the Motion of the Dewetting Contact Line between a Small Bubble and a Solid Surface. Langmuir 19, 6796-6801.
Phan, C. M.; Nguyen, A. V.; Evans, G. M., 2006. Combining hydrodynamics and molecular kinetics to predict dewetting between a small bubble and a solid surface. J. Colloid Interface Sci. 296, 669-676.
Schneemilch, M.; Hayes, R.; Petrov, J.; Ralston, J., 1998. Dynamic wetting and dewetting of a low-energy surface by pure liquids. Langmuir 14, 7047-7051.
Zawala, J.; Kosior, D.; Dabros, T.; Malysa, K., 2016. Influence of bubble surface fluidity on collision kinetics and attachment to hydrophobic solids. Colloid Surf. A 505, 47-55.
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