Formation of AOT Reversed Micelles and W/O Microemulsions

Abstract

The dependence of limiting amounts of solubilized water upon the concentration of sodium 1,2-bis(2-ethylhexyloxycarbonyl)ethanesulfonate (AOT) in apolar solvents was measured by the Karl-Fischer method at 30 °C. In the solubilization regions, two or three states of water, i.e., water bound directly to ionic head groups of AOT and water bound to the hydrated ionic groups or bulk-like water, were found to exist from NMR, ESR, fluorescence, and near infrared spectroscopic measurements. These types of water were related to the formation of reversed and swollen micelles or W/O microemulsions.

Colorimetric Determination of Pectinase Activity towards Pectin in Reverse Micellar System: A Model Study for Bio-scouring of Cotton.

“…These results apparently demonstrate that pectinase solubilized in reverse micellar system has an hydrolyzing activity as has been reported [3]. The influences of the concentration of AOT on the reaction rates are hardly observed and the sufficient activities can be seen in the AOT concentration range as low as 0.025 M. solution would bound to the ionic head groups of AOT molecule as reported by Kon-no et al [22] This means that the enzyme accommodated in an inner part of reverse micelles could not exhibit sufficient hydrolytic activity without proper amount of free water. In the region of relatively high water contents (w>10), on the other hand, excess water might exist as free water (or bulk-like water) in the inner part of reverse micelle.…”

The effect of solvent and counterion variation on inverse micelle CMCs in hydrocarbon solvents

“…Accurate and consistent values of CMCs for inverse micelle formation are lacking in the literature. Several groups have used techniques as disparate as iodine solubilization and mercury interfacial tension to measure CMCs for AOT in different organic solvents, but the results are highly variable between the different studies [15,16,19,20,23,24].…”

Enzyme processing of wool fabrics in a non‐ionic surfactant reverse micellar system

“…At low Wo values, injected water may be used mainly for the hydration of the surfactant molecule. 17,18 As a result, the quantity of free water that is necessary for the enzyme's catalytic reaction in the water-pool may be insufficient. At high water contents, on the other hand, surplus water would be present as free water and provide a suitable environment for the enzyme reaction.…”