pH-Tunable wormlike micelles based on an ultra-long-chain “pseudo” gemini surfactant

Rheological properties of wormlike micelles formed by a pseudo gemini surfactant EAMA and of those without the “gemini” character formed by UC22AMPM in the presence of hydrochloric acid (named EAHCl) have been investigated.

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pH-Responsive Rheological Properties and Microstructure Transition in Mixture of Anionic Gemini/Cationic Monomeric Surfactants

Molecules ◽

10.3390/molecules26165013 ◽

2021 ◽

Vol 26 (16) ◽

pp. 5013

Author(s):

Maozhang Tian ◽

Xi Chen ◽

Xinyuan Zou ◽

Yuchen Qian ◽

Zhang Liu ◽

...

Keyword(s):

Rheological Properties ◽

Gemini Surfactant ◽

Total Concentration ◽

Mixed System ◽

Wormlike Micelles ◽

Spontaneous Curvature ◽

Ph Responsive ◽

Zero Shear Viscosity ◽

Wormlike Micelle ◽

Viscosity Enhancement

Surfactant aggregates have long been considered as a tool to improve drug delivery and have been widely used in medical products. The pH-responsive aggregation behavior in anionic gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C12C3C12(SO3)2) and its mixture with a cationic monomeric surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. The spherical-to-wormlike micelle transition was successfully realized in C12C3C12(SO3)2 through decreasing the pH, while the rheological properties were perfectly enhanced for the formation of wormlike micelles. Especially at 140 mM and pH 6.7, the mixture showed high viscoelasticity, and the maximum of the zero-shear viscosity reached 1530 Pa·s. Acting as a sulfobetaine zwitterionic gemini surfactant, the electrostatic attraction, the hydrogen bond and the short spacer of C12C3C12(SO3)2 molecules were all responsible for the significant micellar growth. Upon adding CTAB, the similar transition could also be realized at a low pH, and the further transformation to branched micelles occurred by adjusting the total concentration. Although the mixtures did not approach the viscosity maximum appearing in the C12C3C12(SO3)2 solution, CTAB addition is more favorable for viscosity enhancement in the wormlike-micelle region. The weakened charges of the headgroups in a catanionic mixed system minimizes the micellar spontaneous curvature and enhances the intermolecular hydrogen-bonding interaction between C12C3C12(SO3)2, facilitating the formation of a viscous solution, which would greatly induce entanglement and even the fusion of wormlike micelles, thus resulting in branched microstructures and a decline of viscosity.

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Studying dispersed and rheological properties of hydrocarbon-containing acid emulsions and their efficiency in removing asphalt-resin-paraffin deposits

Oil and Gas Studies ◽

10.31660/0445-0108-2020-2-128-139 ◽

2020 ◽

pp. 128-139

Author(s):

M. Yu. Shumakher ◽

V. V. Konovalov ◽

A. P. Melnikov

Keyword(s):

Aqueous Solution ◽

Hydrochloric Acid ◽

Rheological Properties ◽

Reaction Rate ◽

Experimental Studies ◽

Efficient Removal ◽

Reservoir Properties ◽

Hydrocarbon Solvents ◽

Formation Zone ◽

Effect Of The Composition

Currently, the treatment of the bottomhole formation zone with acidic compositions is one of the most common methods to intensify the oil inflow. The use of various modified acid compositions increases the efficiency of acid treatments on the bottomhole formation zone. Acid compositions, including those containing hydrocarbon solvents, which contribute to more efficient removal of organic colmatants, affect the reaction rate of the reagent with the rock and processing equipment, change the reservoir properties, etc.The article presents the results of experimental studies, which are aimed at establishing the effect of the composition of hydrocarbon-containing acidic emulsions consisting of an aqueous solution of hydrochloric acid, toluene and Neonol AF 9-10 on their dispersed and rheological properties, as well as their efficiency in removing paraffin deposits.

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