NEXT SPEAKER

October 22, 10:42 AM (GMT-4), Zoom Link

Camille Brigodiot

PhD Student, IFP Energies Nouvelles

Study of dynamic interfacial properties with a microfluidic tensiometer

Surfactants are widely used in various industries: pharmaceutical, cosmetics, petroleum, automotive, food industry. The understanding of the surfactant mass transport towards interfaces is crucial for the design of processes involving creation and/or stabilization of interfaces. Dynamic interfacial properties have been studied in the literature with classical tensiometry methods elucidating the predominant surfactant mass transport (diffusion), while it involves two essential mechanisms: diffusion from the bulk to the interface followed by adsorption onto the interface. This study aims to elucidate dynamics of surfactant transport by studying both diffusion and adsorption steps separately. We have adopted a strategy combining microfluidic technology and classical tensiometry. Microfluidic devices provide insights at short time scales from the millisecond, crucial for adsorption phenomenon while classical tensiometers allow us to unravel surfactant mass transport at larger time and length scales. We have performed dynamic interfacial tension measurements with the EDGE tensiometer developed by Deng et al. [1] for different nonionic surfactants at the water/oil interface, at time scales ranging from 10 ms to 10 s. At short times, the results have been compared with theoretical models and have been found to be driven by adsorption. Combining equilibrium study with the pendant drop method and adsorption theoretical model, kinetics parameters were successfully determined. In conclusion, adsorption and diffusion were successfully described separately and interfacial parameters were determined for specific systems. These results with microfluidics unravel new ways to understand more deeply surfactant mass transport at time and length scales relevant for industrial processes.

[1] Deng B., Schroën K., Steegmans M., Ruiter J. de. Capillary pressure-based measurement of dynamic interfacial tension in a spontaneous microfluidic sensor, Lab on a Chip, 2022, 22, 20, 3860-3868. DOI: https://doi.org/10.1039/D2LC00545J