Intermicellar material exchange in reverse micelles formed by ionic AOT and nonionic Igepal surfactants studied by means of pulse radiolysis. Influence of the temperature

Abstract

Abstract:The recombination of thiocyanate anion radicals, (SCN)~-, formed pulse radiolytically within the water pools of reverse micelles stabilized with anionic AOT and nonionic Igepal surfactants, was proved as an indicator reaction to study intermicellar exchange. It was found that the exchange process is slower in Igepal than in AOT reverse micelles with the same water to surfactant ratio. The apparent activation enthalpy and entropy of the exchange process were determined in different alkanes. For the AOT and Igepal reverse micelles the activation parameters increase with the droplet size, but for the AOT systems they do not significantly change with the increase of droplet concentration. For non-percolated systems the activation parameters for Igepal reverse micelles approach those for AOT reverse micelles. This result supports existing suggestions that the mechanism of intermicellar exchange does not differ in principle between reverse micelles stabilized with ionic and nonionic surfactants.

Versatility of Reverse Micelles: From Biomimetic Models to Nano (Bio)Sensor Design

“…In contrast to normal micelles from aqueous solutions, reverse micelles are characterized by an electrically neutral outer layer such that Coulomb rejection forces do not occur, thus enabling frequent collisions [63]. It is considered that the exchange of content between RMs is a collision-fusion-fission process [73]; the collision of two RMs results in a dimer containing a single aqueous nucleus obtained via the fusion of two component nuclei, and dimer fission results in the formation of two new RMs with redistributed content [74].…”

Versatility of Reverse Micelles: From Biomimetic Model to Nano(Bio)Sensors Design

“…In contrast to normal micelles from aqueous solutions, the reverse micelles are characterized by an electrically neutral outer layer so that Coulomb rejection forces do not occur, thus making possible to frequently perform collisions [53]. It is considered that the exchange of content between RMs is a collision-fusion-fission process [63]: by collision of two RMs results a dimer containing a single aqueous nucleus obtained by the fusion of the two component nuclei and the dimer fission results in the formation of two new RMs with redistributed content [64].…”