Percolation Behavior of Nonionic Reverse Micellar Solution

Aramaki, Kenji; Ichikawa, Kotoko; Shrestha, Lok Kumar

doi:10.1246/cl.161127

Cited by 2 publications

(2 citation statements)

References 23 publications

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“…This implies that SAXS can selectively detect only the hydrophilic core of the reverse micelles. Therefore, the derived p ( r ) must be recognized as a measure of the micellar core structure. − Symmetrical bell-shaped p ( r ) obtained for the water-free system (Figure b) indicates the formation of spheroid-type reverse micelle with maximum dimension, D max , of ca. 13 nm.…”

Section: Resuts and Discussionmentioning

confidence: 83%

Demonstration of a Novel Charge-Free Reverse Wormlike Micelle System

et al. 2018

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We demonstrate a novel charge-free reverse wormlike micelle (RWLM) consisting of a ternary mixture of a nonionic amphiphilic block copolymer, fatty acid alkyl ester oil, and water under ambient conditions. Nonionic amphiphile tetra-[poly(oxyethylene)-poly(oxybutylene)]pentaerythrityl ether (TEBPE) self-assembled into spheroid-type micelles in nonaqueous media isopropyl myristate (IPM) with viscosity comparable to that of IPM. The addition of water increases viscosity only slightly up to a certain concentration of water and then drastically, demonstrating the sphere-to-wormlike micelle transition as confirmed by small-angle X-ray scattering. Further increase in water decreases the viscosity after attaining a maximum value. The zero shear viscosity (η) of the 10 wt % TEBPE/IPM system reached the maximum at 2.6 wt % water and ca. 56 Pa·s, which is ∼fivefold higher than that of water. Dynamic rheological measurements on the highly viscous solutions confirmed the viscoelastic behavior and could be described by the Maxwell model. Conductivity, measured in the presence of a conductive probe, 1-ethyl-3-methylimidazolium tetrafluoroborate, was found to be higher for viscous samples compared to the nonviscous samples, suggesting the static percolation caused by the RWLM formation. Decrease in η and conductivity beyond a maximum suggests the shortening of reverse micelles. A similar behavior has been observed in other fatty acid alkyl ester oils of different alkyl chain lengths. Note that most of the RWLM systems previously reported are based on phosphatidylcholine (PC). Formulation and structure-properties related to non-PC-based RWLMs have been rarely explored. Non-PC-based RWLMs using chemically stable and low-cost synthetic molecules can be applied not only in pharmaceuticals and cosmetics but also in a wide range of applications including drag reduction agents for nonaqueous fluids and as a template for nanomaterial synthesis.

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Section: Resuts and Discussionmentioning

confidence: 83%

Demonstration of a Novel Charge-Free Reverse Wormlike Micelle System

et al. 2018

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“…[25,26] increase percolation as observed from the drop in threshold temperature whereas for other additives such as sodium salicylate, toluene, benzene etc. [27] the percolation was delayed. This suggests the existence of smaller reverse micelles and smaller aqueous pools in the latter systems.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Hydrodynamic Radius of AOT/n-heptane/Water Reverse Micellar System Through Altered Electrostatic Interactions and Molecular Self-Assemblies

Das

Mandal

et al. 2021

J Fluoresc

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We have demonstrated a unique approach to alter the aqueous pool size of an AOT/n-heptane/water reverse micellar system. A positively charged dye Rhodamine B (RhB) and negatively charged Rose Bengal (RB) were incorporated in the reverse micellar pool to investigate the effect of electrostatic interactions and stacking effects among the dye molecules on the AOT/nheptane/water interface. Dynamic light scattering revealed increase in reverse micellar pool size in presence of positively charged dye aggregates at the oil-water interface. However, less expansion was observed in presence of negatively charged dye aggregates (RB). This confirms the role of electrostatic interaction in modulating the hydrodynamic radius. A headto-tail type of stacking of RhB molecules at the interface favors this expansion. The differences in stacking of the two dyes inside the reverse micelles and their torsional mobility indicated the role of the reverse micellar interface and H-bonding ability of the microenvironment on dye aggregation. Conductivity measurements demonstrated a significant drop in percolation temperature of the reverse micellar system in presence of dye aggregates. This confirms the effect of dye aggregation and electrostatic interaction on such expansion. This strategy can be exploited for solubilizing greater amounts and a wider variety of drug molecules in microemulsions.

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Percolation Behavior of Nonionic Reverse Micellar Solution

Cited by 2 publications

References 23 publications

Demonstration of a Novel Charge-Free Reverse Wormlike Micelle System

Demonstration of a Novel Charge-Free Reverse Wormlike Micelle System

Enhanced Hydrodynamic Radius of AOT/n-heptane/Water Reverse Micellar System Through Altered Electrostatic Interactions and Molecular Self-Assemblies

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