Effect of Counterions on the Interfacial Tension and Emulsion Droplet Size in the Oil/Water/ Dodecyl Sulfate System

The effects of the size of counterions of anionic dodecyl sulfate surfactants on the interfacial tension and emulsion droplet size were investigated by the Wilhelmy plate method and optical microscopy. The size of nonhydrated counterions increases in the order Li + <NA + <K + <CS + . This order is reversed when these ions are hydrated by water due to the strongest hydration force of lithium ion