Rheological and calorimetric study of alkyltrimethylammonium bromide-sodium salicylate wormlike micelles in aqueous binary systems

Clinckspoor, Karl Jan; Jorge, Laila Lorenzetti; Hoffmann, H.; Sabadini, Edvaldo

doi:10.1016/j.jcis.2018.01.024

Cited by 16 publications

(14 citation statements)

References 66 publications

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“…The curves were separated into three main groups, based on the magnitude of their variation of energies: low energy, observed for titration of Bz, 2ClBz, and 2,6ClBz; intermediary energy, for 2,3ClBz, 2,4ClBz, 3ClBz, and 4ClBz; and high energy, for 3,4ClBz. The last two groups present a specific thermogram profile, which is considered as a signature of WLM formation when aromatic anions are titrated with cationic surfactants. ,, Because the concentration of C 14 TAB in the syringe is higher than its cmc, the variation of energy observed in the beginning of the titration is associated with the breaking of the C 14 TAB micelles and subsequent formation of ionic pairs between the unimers of the surfactant and the aromatic anions. By adding more C 14 TAB, the critical concentration value is reached and the aggregate is formed.…”

Section: Resultsmentioning

confidence: 99%

“…Molecules of surfactants can self-assemble in solution in different ordered structures such as spheres, rods, wormlike, vesicles, and so on. − Wormlike micelles (WLMs) can reach hundreds of nanometers in length, and in the concentrated regime, their chains can entangle to form three-dimensional network structures. They have been attracting much attention not only for academic but also for applied interests.…”

Section: Introductionmentioning

confidence: 99%

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Probing the Formation of Wormlike Micelles Formed by Cationic Surfactant with Chlorobenzoate Derivatives

et al. 2019

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The energy released when tetradecyltrimethylammonium bromide (C 14 TAB) is combined with different derivatives of chlorobenzoates in an isothermal titration calorimeter (ITC) allows a direct evaluation of the spontaneity of the threading of the aromatic anions into the micellar palisade. The comparison between the enthalpimetric curves with the ones for viscosity of the solutions, hydrodynamic radii of the aggregates (dynamic light scattering experiments), and the fraction of aromatic anions incorporated (diffusion-ordered spectroscopy experiments) allows the establishment of the variations of enthalpy with formation, growth, and decrease of the wormlike micelles (WLMs). The formation of WLMs with C 14 TAB is very favored (very exothermic) for titrations of chlorobenzoate derivatives which present the chlorine atom in positions 3 or 4 of the aromatic ring. However, the aggregation is highly unfavorable if chlorine is at position 2 of chlorobenzoate. According to the results, the high potential of the ITC to determine critical concentrations and the energies associated with the aggregation of a cationic surfactant and aromatic anions for the formation of WLMs was demonstrated.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Probing the Formation of Wormlike Micelles Formed by Cationic Surfactant with Chlorobenzoate Derivatives

et al. 2019

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“…However, it is also possible to change the hydrophobic surface of the WLM by adding small amphiphilic molecules such as isopropanol or 1.3-dihydroxybutane to the micellar solution. 31 These small molecules bind to the hydrophobic surface of the micelles and make it hydrophilic. As a consequence, the WLM can no longer bind to each other and the viscosity has to decrease.…”

Section: Resultsmentioning

confidence: 99%

“…Unfortunately, surfactants with such head groups are commercially not available and measurements on such systems could not be made. However, it is also possible to change the hydrophobic surface of the WLM by adding small amphiphilic molecules such as isopropanol or 1.3-dihydroxybutane to the micellar solution . These small molecules bind to the hydrophobic surface of the micelles and make it hydrophilic.…”

Section: Resultsmentioning

confidence: 99%

Evidence of Sticky Contacts between Wormlike Micelles in Viscoelastic Surfactant Solutions

Thurn

Hoffmann

2019

Langmuir

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Many cationic surfactants form highly viscoelastic solutions at concentrations of only a few percent. These solutions contain wormlike micelles (WLM) which can be several micrometers long. The structural relaxation time, τ s in these solutions can be as long as many seconds, and the zero-shear viscosity can be in the range of 10 6 Pas. Electric birefringence measurements on such solutions showed four different relaxation times with increasing concentration. The two shortest ones, τ 1 and τ 2 in the μs region were due to the alignment of small rodlike or ringlike micelles. The third one, τ 3 , was observed in the viscoelastic region in the ms region and finally, a fourth one, τ 4 , which was the same as the structural relaxation time, τ s . In this article, it is shown that the τ 3 process is due to the formation and opening of contacts between the WLM. The reason for the contacts is the attraction between the WLM which is due to the hydrophobic surfaces of the micelles. The contacts crosslink the WLM and thus form a threedimensional network. This network is the reason for the high viscosity and viscoelastic properties of the samples. If the attraction between the WLM is reduced by adding glycerol to the solution, the viscosity of the solution breaks down. The same happens if the surface of the WLM is made hydrophilic by the addition of small amphiphilic molecules. The WLM are not destroyed by these procedures.

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“…In the salt-curve, the viscosity, or more precisely the zero-shear viscosity, is plotted as a function on the molar ratio R = C salt / C surf , where C salt is the salt concentration and C surf is the surfactant concentration. Depending on the interactions between a salt and a surfactant molecule, the salt-curve features either one or two viscosity maxima, i.e., a dromedary or camel shape. ,, Similar curves are formed by the addition of cosurfactants or fragrances to surfactant solutions. − The increase in viscosity is commonly linked to the increase of micellar length before the first maximum, caused by neutralization and core shielding with aromatic ions. The decrease in viscosity at higher salt concentration is associated with the enhanced screening and possible charge inversion at the isoelectric point of WLMs .…”

Section: Introductionmentioning

confidence: 99%

Higher Salt Hydrophobicity Lengthens Ionic Wormlike Micelles and Stabilizes Them upon Heating

et al. 2020

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Tuning the rheological properties of surfactant solutions by charge screening is a convenient formulation tool in cosmetic, household, oil recovery, drag-reduction, and thickening applications. Surfactants self-assemble in water, and upon charge screening and core shielding, they grow into long wormlike micelles (WLMs). These are valuable model systems for soft matter physics, and the most explored formulation is hexadecyl-trimethylammonium bromide (CTAB) and sodium salicylate (NaSal). Replacing NaSal with aromatic salts of altered hydrophobicity results in different penetration of the additive in the CTAB micellar core. This altered penetration depth will determine the anisotropic micellar growth that tailors the viscoelastic response. Sodium 4-methylsalicylate (mNaSal) is a higher hydrophobicity alternative to NaSal, requiring less additive to induce strong changes in the viscoelastic properties. Herein, we provide a comparative study of the mNaSal/CTAB system with the reference NaSal/CTAB over a range of temperatures and salt concentrations. The findings from the well-known NaSal/CTAB pair are transferred to the mNaSal/CTAB system, revealing the origins of the WLM solution’s viscoelastic properties by discerning contributions from charge screening and micellar core shielding upon small differences in hydrophobicity.

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Rheological and calorimetric study of alkyltrimethylammonium bromide-sodium salicylate wormlike micelles in aqueous binary systems

Cited by 16 publications

References 66 publications

Probing the Formation of Wormlike Micelles Formed by Cationic Surfactant with Chlorobenzoate Derivatives

Probing the Formation of Wormlike Micelles Formed by Cationic Surfactant with Chlorobenzoate Derivatives

Evidence of Sticky Contacts between Wormlike Micelles in Viscoelastic Surfactant Solutions

Higher Salt Hydrophobicity Lengthens Ionic Wormlike Micelles and Stabilizes Them upon Heating

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