Effects of interfacial specific cations and water molarities on AOT micelle-to-vesicle transitions by chemical trapping: the specific ion-pair/hydration model

Liu, Changyao; Wang, Yuzhao; Gao, Yanfei; Zhang, Yongliang; Zhao, Li; Xu, Bin; Romsted, Laurence S.

doi:10.1039/c8cp05987j

Cited by 19 publications

(27 citation statements)

References 67 publications

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“…In this sense, the ammonium ion can interact closely with the R‐sulfonate considered chaotropic, according to Collins' concept of matching water affinities (Collins, ; Kunz, ). As a consequence, a chaotropic salt can reduce the effects of head group repulsion, favoring the decrease in interfacial curvature and promoting microemulsion formation (Chen et al, ; Leontidis, ; Liu et al, ; Santos et al, ). This phenomenology is related to the phenomena of “hydration force,” which influences the agglomeration and interfacial activity of surfactant molecules due to the reduction of the hydration repulsion effects (Evans and Ninham, ; Israelachvili and Wennerstrom, ; Kralchevsky et al, ).…”

Section: Resultsmentioning

confidence: 99%

How the Influence of Different Salts on Interfacial Properties of Surfactant–Oil–Water Systems at Optimum Formulation Matches the Hofmeister Series Ranking

Vera

Salazar-Rodríguez

Márquez

et al. 2020

J Surfact & Detergents

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In this work, we present the effects of salts on sodium dodecyl benzene sulfonate micellization and on the interfacial performance of a sodium dodecyl benzene sulfonate-heptane-brine system at optimum formulation, i.e., hydrophilic-lipophilic deviation (HLD) = 0. In order to do that, interfacial tension and dilational interfacial rheology properties of surfactant-heptane-water systems at optimum formulation are measured using an interfacial spinning drop tensiometer with an oscillating velocity, which can accurately measure interfacial rheology properties at both low and ultralow interfacial tensions. The brines used contain one of the following salts: MgCl 2 , CaCl 2 , NaCl, NH 4 Cl, NaNO 3 , CH 3 COONa, or Na 2 SO 4 . We performed a one-dimensional salinity scan with each of these salts to achieve an optimum formulation. In relation to the Hofmeister series, we found that, at optimum formulation, systems with chaotropic ions (NH 4 + , NO 3 − ) present interfaces with ultralow interfacial tensions, very low dilational modulus, and a low phase angle, whereas kosmotropic ions (Mg 2+ , Ca 2+ , SO 4 −2 ) generate high interfacial tension and high rigidity monolayers. Intermediate ions in the Hofmeister series (Na + , CH 3 COO − , Cl − ) present interfaces with intermediate properties. Furthermore, according to the Hofmeister series, interfaces can be respectively ordered from higher to lower rigidity for surfactant counterions Mg 2+ > Ca 2+ > Na + > NH 4 + and coions SO 4 2− > CH 3 COO -> Cl − > NO 3 −, which correspond to a saltingout (highest rigidity) and salting-in (lowest rigidity) effect. We observed that counterions have a more significant effect on surfactant-oil-water system properties than those that act as coions.Keywords Hofmeister series Á Interfacial rheology Á Microemulsion Á Micellization Á Salt effects Á Ultralow interfacial tension J Surfact Deterg (2020) 23: 603-615.

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Section: Resultsmentioning

confidence: 99%

How the Influence of Different Salts on Interfacial Properties of Surfactant–Oil–Water Systems at Optimum Formulation Matches the Hofmeister Series Ranking

Vera

Salazar-Rodríguez

Márquez

et al. 2020

J Surfact & Detergents

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“…Therefore, the interaction between KCGl headgroup and NH 4 is stronger than other hydrophobic cations. Second, possible hydrogen bonding 49 between NH 4 and amino acid headgroups may also contribute to the packing between amphiphiles with added NH 4 . Thus, the IFT at high surfactant concentration is lower for ammonium ions compared to TMA and TEA .…”

Section: Resultsmentioning

confidence: 99%

Effect of Added Tetraalkylammonium Counterions on the Dilational Rheological Behaviors of N-Cocoyl Glycinate

et al. 2020

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Ion specific effect, which was first reported by Hofmeister in 1888 1 , has been reported in tons of systems with charged interfaces or surfaces, including surfactant aggregates, supramolecular structures, enzymes, and polymers over the past several decades 2 5 . Counterions in added salts are an important factor affecting the intermolecular interaction, surface activity, micellization, and aggregate morphological transition of ionic surfactants. Various organic and inorganic counterions are often used because they not only affect the interfacial behaviors of the surfactants, but also affect their self-aggregation structures 6 11 .

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“…Water actively influences the hydration and assembling behavior of biological molecules, such as polypeptides, , which is vaguely expressed as hydrophobic effects (HEs). − Although the effect of salts on the hydration of biological and synthetic macromolecules, known as the Hofmeister effects, has been extensively studied, − the molecular nature of this HE effect and its consequence on the assembling behavior are not clear. − It has been reported that the ionic groups pendent to solutes substantially influence the assembling behavior. − The long-range effect of water hydrogen bonding structure perturbated by ionic groups is proposed for the discussion in some research studies. − However, it is, although controversial, generally considered that the solvation of individual ions does not create a long-range effect for the Hofmeister effects. , This perplexity would be clarified if the ionic-group-dependent hydration could be analyzed on a molecular level.…”

Section: Introductionmentioning

confidence: 99%

“…Self-assembled morphologies of surfactants are found to be dependent on the ionic end group, which is usually rationalized by the variation in the packing parameters caused by the ion pair. 22,23,44 This explanation cannot justify the variable assembling behavior of block copolymers depending on the ionic end groups. 20,21 This perplexity is caused by the negligence of the role of hydration in self-assembly.…”

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confidence: 99%

Active Role of Water in the Hydration of Macromolecules with Ionic End Group for Hydrophobic Effect-Caused Assembly

Liu

Chen

et al. 2020

Macromolecules

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The role of water in the hydration and aqueous assembly of hydrophobic P+X– (P+: macromolecular phosphonium cation, X–: anion) was investigated via complementary Fourier transform infrared (FT-IR) and low-field NMR analyses. The hydration of the macromolecular backbone was dependent on X–. When X– is I–, the ionic end group ordered water molecules that exerted a detectable long-range effect of dehydrating the backbone. The consequent hydrophobic interaction drove the aqueous assembly of P+I– into micelle-like aggregates, with the ionic group exposed to water. In contrast, the ion pair with a hydrophobic anion of [BPh4]− was not able to hold water and did not deplete the hydration water. The hydrated backbone endowed the assembly of P+[BPh4]− into vesicles that were driven by hydration interactions. This elucidation at the molecular level is craved to progress the aqueous supramolecular chemistry.

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Effects of interfacial specific cations and water molarities on AOT micelle-to-vesicle transitions by chemical trapping: the specific ion-pair/hydration model

Abstract: Added salts induce micelle-to-vesicle transitions at specific cation concentrations in Hofmeister order by forming polar headgroup–counterion pairs that release water.

Cited by 19 publications

References 67 publications

How the Influence of Different Salts on Interfacial Properties of Surfactant–Oil–Water Systems at Optimum Formulation Matches the Hofmeister Series Ranking

How the Influence of Different Salts on Interfacial Properties of Surfactant–Oil–Water Systems at Optimum Formulation Matches the Hofmeister Series Ranking

Effect of Added Tetraalkylammonium Counterions on the Dilational Rheological Behaviors of N-Cocoyl Glycinate

Active Role of Water in the Hydration of Macromolecules with Ionic End Group for Hydrophobic Effect-Caused Assembly

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