Inverse micelles as charge carriers in nonpolar liquids: Characterization with current measurements

Despite the increasing importance of charges in nonpolar liquids for practical applications and fundamental research, their origin, nature and behavior are not yet completely understood. The most widely (but not generally) accepted view is that in mixtures of a nonpolar liquid with surfactant, inverse micelles act as charge carriers. A lot of research is still needed to support this view, and to gain a fundamental understanding of the electrical properties of inverse micellar solutions. In this article, we discuss transient current measurements as a valuable technique for the characterization of charged inverse micelles in nonpolar liquids, and we illustrate how they can be used to study a large number of properties, such as the concentration of both neutral and charged inverse micelles, their mobility, size, aggregation number and valency, and their behavior and generation in the bulk and at surfaces.

Graphical abstractThe origin, nature, and behavior of charges in nonpolar liquids are not completely understood. If surfactant is present, inverse micelles can stabilize charge in their polar core. Transient current measurements, in which a voltage step is applied over a thin layer of liquid, are a valuable tool to study the electrical behavior of such micellar solutions.Figure optionsDownload full-size imageDownload high-quality image (113 K)Download as PowerPoint slideHighlights► Inverse micelles in nonpolar liquids can stabilize electrical charges. ► Electric transient current measurements are a valuable tool to study inverse micelles. ► Inverse micelle concentration, size and charge are found from fast transient currents. ► Generation of charged inverse micelles is studied from the quasi steady state current. ► Disproportionation and surface desorption generate charged inverse micelles.