Thermodynamics of micelle formation of the ephedrine-based chiral cationic surfactant DMEB in water, and the intercalation of DMEB in montmorillonite

Páhi, Annamária B.; Varga, Dénes; Király, Zoltán; Mastalir, Ágnes

doi:10.1016/j.colsurfa.2007.06.056

Cited by 12 publications

(11 citation statements)

References 48 publications

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“…DMEB had low solubility at room temperature, but when dissolved in H 2 O, formed vesicles when the concentration was above its critical micelle concentration (4 mM) and below 50 mM at 30°C. 37,38 By increasing the concentration of DMEB, the size (Supporting Information Figure S1a) sharply increased from 20-50 nm of vesicle (Supporting Information Figure S1b) to 5-20 μm of coacervate (Supporting Information Figure S1c) at 50 mM DMEB, which corresponded to the vesicle-to-coacervate transition. When monovalent salt was added (C NaCl > 100 mM), either vesicles or coacervates stably existed at 25°C by mixing the transparent DMEB and NaCl stock solutions.…”

Section: Resultsmentioning

confidence: 97%

A Multiresponsive Transformation between Surfactant-Based Coacervates and Vesicles

et al. 2021

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Low-molecular weight surfactants have significant potential as building blocks for prebiotic organization. However, reports about surfactant-based coacervates as protocell models capable of reversible transformation are scarce. Herein, we develop a simple system made of a surfactant (-)-N-dodecyl-N-methylephedrinium bromide (DMEB) and inorganic salts that is capable of spontaneous formation of vesicles, coacervates, and the reversible transformation between the two states. The coacervates are stable over a wide range of pH values and salt concentrations, and they contain a disordered sponge-like internal microstructure, which leads to effective encapsulation of a broad range of solutes and biomacromolecules such as DNA and green fluorescent protein (GFP). They provide an advantageous chemical environment in which the activity of enzymes, including apyrase, is enhanced. Strikingly, these coacervates can undergo a reversible transformation to small, well-defined vesicles by changing the temperature and surfactant or salt concentrations. Moreover, we show that this transition can be dynamically controlled by chemical reactions. The cycling between open (coacervates) and closed (vesicles) compartments could facilitate the encapsulation of solutes within membrane-bound vesicles, and our results demonstrate that these surfactantbased coacervates constitute superior protocells capable of a reversible droplet-vesicle transition.

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Section: Resultsmentioning

confidence: 97%

A Multiresponsive Transformation between Surfactant-Based Coacervates and Vesicles

et al. 2021

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“…Generally, cmc of non-ionic surfactants decreases regularly with increase in temperature (till critical solution temperature). However, ionic surfactants show a more interesting behavior: cmc decreases to a certain value (cmc m ) and then increases with continuous increase in temperature (U-shaped behavior) [10][11][12][13][14]. The temperature at cmc m (T m ) for both non-ionic and ionic surfactants increases as the hydrophobicity of the surfactant decreases.…”

Section: Introductionmentioning

confidence: 99%

Influence of Temperature and Salt on Association and Thermodynamic Parameters of Micellization of a Cationic Gemini Surfactant

Kumar¹

2012

J. Appl. Sol. Chem. Model.

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Association behavior of a gemini surfactant, N,N'-(ethane-1,2-diylbis(oxy))bis(2-oxoethane-2,1-diyl))bis(N,Ndimethylhexadecan-1-aminium) chloride, has been studied conductometrically at different temperatures (293.15 to 338.15 K) in aqueous and aqueous ethylene glycol solvents. The association studies were also performed in aqueous salt solution (sodium chloride, NaCl or sodium salicylate, NaSal). Critical micelle concentration (cmc) decreases and then increases with continuous increase in temperature (U-shaped behavior). The temperature (Tm) corresponds to lowest cmc (cmcm) has been found 325 K for both the solvents (water and water + ethylene glycol). However, cmc increases in mixed solvent (water + ethylene glycol). The Tm has been shifted to lower temperature in the presence of salt. The shifting in Tm was dependent upon the nature of the counter ion. The cmc-temperature variation can be represented by a power law relationship. Relevant thermodynamic parameters have been evaluated and discussed on the basis of the nature of the solvent / counter ion. The enthalpy-entropy compensation plots exhibit linearity. The compensation temperature (Tc) and enthalpy change (H * mic) have been computed for various surfactant-solvent systems.

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“…For example, the similarly structured sodium alkyl sulfates and sodium alkyl sulfonates exhibit striking differences in their interactions with cationic surfactants , and polymers, , which is related to the different charge density between the two headgroups based on quantum chemical calculations. With regards to quaternary ammonium surfactants the structure of headgroup is various and adjustable − because of the convenience of introducing a different number of different substitution groups onto the nitrogen atom.…”

Section: Introductionmentioning

confidence: 99%

Effect of Headgroup Size on the Thermodynamic Properties of Micellization of Dodecyltrialkylammonium Bromides

et al. 2010

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The micellization of dodecyltrimethyl/ethyl/propyl/butylammonium bromide (C 12 NM, C 12 NE, C 12 NP, and C 12 NB) was investigated by electrical conductivity measurements at different temperatures T. In the investigated temperature range, (15 to 45) °C, both the critical micelle concentration (cmc) and the degree of counterion association (β) decreased with the increase of headgroup size. The cmc as a function of T showed a typical U-shaped relationship. The temperature of the minimum of U-shaped curve (T min ) increased with the incremental chain length in the headgroups, which was the reverse to the previous results for quaternary ammonium surfactants that T min decreased with the increment in the hydrophobic tails. The β approximately exhibited a linear decrease with raising T. Nonlinearity was observed both in ln(cmc) versus N c and in Δ mic G°versus T, where N c was the carbon number in the headgroups and Δ mic G°was the standard Gibbs energy of micellization. C 12 NM and C 12 NE resembled each other in the thermodynamics of micellization, but they behaved considerably differently from either C 12 NP or C 12 NB in the dependence of ln(cmc) on N c , in the decreasing rate of Δ mic G°versus T, and in the variation of thermodynamic properties with T. All of the surfactants exhibited the enthalpy-entropy compensation phenomenon. The large value of standard entropy of micellization (Δ mic S°) of C 12 NB compared with the others could be attributed to the strong hydrophobicity of the tributyl headgroup.

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Thermodynamics of micelle formation of the ephedrine-based chiral cationic surfactant DMEB in water, and the intercalation of DMEB in montmorillonite

Cited by 12 publications

References 48 publications

A Multiresponsive Transformation between Surfactant-Based Coacervates and Vesicles

A Multiresponsive Transformation between Surfactant-Based Coacervates and Vesicles

Influence of Temperature and Salt on Association and Thermodynamic Parameters of Micellization of a Cationic Gemini Surfactant

Effect of Headgroup Size on the Thermodynamic Properties of Micellization of Dodecyltrialkylammonium Bromides

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