Fluid Dynamics of Droplets as a Useful Tool to Determine Coverage and Adsorption Kinetics of Surfactants

Abstract

In many industrial applications impurities such as surfactants occur. These interfacially active molecules adsorb at liquid-liquid interfaces where they influence the occurring transport processes, which again affect reaction rates of multiphase reactions or contact times in extraction columns etc. To quantify the influences on the given applications, the interfacial coverage of the liquid-liquid interface with surfactant molecules must be known. The measurement of the fluid dynamics of single droplets provides a sensitive tool to capture any interfacial phenomena which changes the interfacial characteristics. This method was tested by applying two different surfactants in the system water/1-octanol. In some cases, the determination of the fluid dynamics provides a more reliable method for determining changes of the interfacial characteristics than the measurement of the interfacial tension.

Surface remobilization of buoyancy‐driven surfactant‐laden drops at low reynolds and capillary numbers

“…More quantitative studies followed such as by Edge and Grant using drops of dichloroethane settling in water containing sodium lauryl sulfate; Skelland et al using chlorobenzene drops settling in water containing anionic, cationic, and nonionic surfactants; and Bel Fdhila and Duineveld using air bubbles rising in water containing Triton X‐100. Malysa et al determined the concentration of surfactant necessary to affect bubble velocities rising in water containing n ‐butanol, α‐terpineol, and n ‐octanoic acid, while more recently Paul et al used settling drop velocities as a method for estimating the adsorption of sodium dodecyl sulfate (SDS) and Triton X‐100 surfactants on drop surfaces.…”

Tropfenbewegung und Stofftransport in technischen Flüssig/flüssig‐Systemen. Teil 1: Einzeltropfensedimentation ohne Grenzflächeneffekte

“…Durch die intensive Wechselwirkung zwischen Impuls‐ und Stofftransport ist mit dem Auftreten der o. g. Grenzflächenphänomene in der Regel ein charakteristisches Sedimentationsverhalten verbunden, das als sensitiver Indikator zur Vorhersage des Stofftransports dienen kann 1, 6. Der Artikel konzentriert sich auf Einzeltropfenexperimente, deren Einsatz als Schlüsselexperiment bspw.…”

Influence of Surface‐Modified Nanoparticles on the Hydrodynamics of Rising Bubbles

“…Many industrial dispersions, such as emulsions, foams, and suspensions, contain surfactants, proteins, and colloidal particles 1–5. For a long time, the multiphase flow behavior in these systems has been a part of scientific research due to their application in many technological processes for food, pharmacology, or oil recovery 6–8.…”