Exploring the charging mechanisms in non-aqueous multiphase surfactant solutions, emulsions and colloidal systems via conductivity behaviors predicted with eyring's rate process theory

Abstract

The common charging agents and charging mechanisms in non-aqueous multiphase systems available in the literature are analyzed, and the conductivity equations derived on the basis of the charging mechanisms with the Eyring's rate process theory are compared with experimental observations. The popular charging mechanisms in non-aqueous systems, such as the ion preferential absorption, ion pair dissociation, and micelle disproportionation/fluctuation models, are found to be incapable of explaining all experimental evidences. Particularly, the ion pair dissociation and micelle disproportionation/fluctuation models apparently suffer a major drawback: how charges are separated and most importantly how charging entities are stabilized in non-aqueous systems, are not adequately addressed; in low dielectric constant non-aqueous media separated ions tend to bind together rather than stay separately. A new charging mechanism incorporating an electric field internally available or externally applied into the charging process is proposed to explain charge separations and stabilizations. The conductivity equations derived on the basis of this new mechanism predict that conductivity should linearly increase with both the electric field and the concentrations of inverse micelles in very low concentration regions, which is consistent with experimental evidences.

Structure and conductivity of AOT solutions in n‐hexadecane‐chloroform mixtures

“…In addition, the linear nature of the dependences ( Supporting Information Fig. S3) indicates that the formation of ions in both cases proceeds by the disproportionation mechanism (2АОТ ↔ АОТ + + АОТ − and 2M ↔ M + + M − ) rather than by dissociation [31, 44].…”

“…In the region of concentrations above CMC, charges appear according to the fluctuation mechanism [28] via the disproportionation reaction of uncharged micelles (2M ↔ M + + M − ) [29, 30]. In this region, conductivity is proportional to the surfactant concentration [30, 31]. In [31], along with the indicated mechanisms, the emergence of charges in micelles due to ionic adsorption is also considered.…”

“…In this region, conductivity is proportional to the surfactant concentration [30, 31]. In [31], along with the indicated mechanisms, the emergence of charges in micelles due to ionic adsorption is also considered. Impurity ions or trace amounts of water can be solubilized by reverse micelles of nonionic surfactants.…”

Space charge limited release of charged inverse micelles in non-polar liquids

“…In thermal equilibrium a small fraction of these inverse micelles is charged (to +e or -e) and called charged inverse micelles (CIMs) [2][3][4] . The formation of CIMs, their charge stabilization and electrodynamical properties have been studied widely 2,3,[5][6][7][8][9][10][11] . However, not all aspects of the charging dynamics have been clarified.…”

Development of methods for controlling organic impurities in wastewater treatment

“…В основе такого подхода учитывается аддитивный вклад в электропро-водность свободных противоионов, поверх-ностно-активных ионов, а также мицелл как макроионов. Измерение концентрационной зависимости электрической проводимости растворов ионогенных ПАВ, является наиболее распространенным способом определения кри-тической концентрации мицеллообразования (ККМ), степени связывания противоионов мицеллами и чисел агрегации последних [6][7][8][9][10][11].…”