Chemical shift changes on micellization of linear alkyl benzenesulfonate and oleate

Das, Sandip; Bhirud, R. G.; Nayyar, N. K.; Narayan, K. S.; Kumar, Vinod

doi:10.1021/j100197a059

Cited by 35 publications

(43 citation statements)

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“…Such a large extent of upfield chemical shifts in the proton NMR spectra of surfactant systems is not common. Only recently have Kumar and co-workers observed similar upfield chemical shifts in their studies with linear alkyl benzenesulfonate and oleate micellar systems (23,24). Aromatic compounds possessing a phenolic-OH functionality are more hydrophilic compared to other compounds used for the present study.…”

Section: Discussionsupporting

confidence: 51%

Solubilization Site of Organic Perfume Molecules in Sodium Dodecyl Sulfate Micelles: New Insights from Proton NMR Studies

Suratkar

Mahapatra

2000

Journal of Colloid and Interface Science

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Section: Discussionsupporting

confidence: 51%

Solubilization Site of Organic Perfume Molecules in Sodium Dodecyl Sulfate Micelles: New Insights from Proton NMR Studies

Suratkar

Mahapatra

2000

Journal of Colloid and Interface Science

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“…This last feature is also observed for free oleate molecules below their critical micelle concentration. 57 In any case, under these conditions, the anti-parallel arrangement of two adjacent SL molecules is a hypothesis to be considered with good probability where the free COO -group would be solvated by water both inside and outside the tubule. Whatever the configuration adopted by adjacent SL molecules, the micellar surface becomes negatively charged with pH.…”

Section: E-mentioning

confidence: 99%

Unusual, pH-Induced, Self-Assembly Of Sophorolipid Biosurfactants

et al. 2012

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International audienceAn increasing need exists for simple, bioderived, nontoxic, and up-scalable compounds with stimuli-responsive properties. Acidic sophorolipids (SL) are glucose-based biosurfactants derived from the yeast broth of Candida bombicola (teleomorph: Starmerella bombicola). The specific design of this molecule, a sophorose head with a free end-COOH group at the end of the alkyl chain, makes it a potentially interesting pH-responsive compound. We have specifically investigated this assumption using a combination of small angle neutron scattering (SANS), transmission electron microscopy under cryogenic conditions (Cryo-TEM), and nuclear magnetic resonance (NMR) techniques and found a strong dependence of SL self-assembly on the degree of ionization, α, of the COOH group at concentration values as low as 5 and 0.5 wt %. At least three regimes can be identified where the supramolecular behavior of SL is unexpectedly different: (1) at low α values, self-assembly is driven by concentration, C, and micelles are mainly identified as nonionic objects whose curvature decreases (sphere-to-rod) with C; (2) at mid α values, the formation of COO– groups introduces negative charges at the micellar surface inducing an increase in curvature (rod-to-sphere transition). Repulsive electrostatic long-range interactions appear at this stage. In both regimes 1 and 2, the cross-section radius of the micelles is below 25 Å. This behavior is concentration independent. (3) At α = 1, individual micelles seem to favor the formation of large netlike tubular aggregates whose size is above 100 nm. Such a complex behavior is very unique as it is generally not observed for common alkyl-based surfactants in concentration ranges below 5–10 wt %

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“…The tendency of different surfactants to form mixed micelles is governed by their attractive (synergistic) or repulsive (antagonistic) interactions and is often explained from the β parameter estimated using Rubingh ' s regular solution theory (6). Extensive studies have been carried out on various mixed surfactant systems like anionic-anionic (7)(8)(9), cationic-cationic (10)(11)(12), anionic-nonionic (13)(14)(15), cationic-nonionic (16,17), cationicanionic (18,19), and nonionic-nonionic (20). Considerable interaction has been reported for ionic-nonionic systems, whereas weak or negligible interaction has been observed for similarly charged surfactants.…”

mentioning

confidence: 96%

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

Vora

George

Desai

et al. 1999

J Surfact & Detergents

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Critical micelle concentrations (CMC) were obtained from tensiometric studies on several binary surfactant mixtures (anionic-anionic, cationic-cationic, anionic-nonionic, and cationic-nonionic) in water at different mole fractions (0-1). The composition of mixed micelles and the interaction parameter β, evaluated from the CMC data for different systems using Rubingh's theory, are discussed. Marked interaction is observed for ionic-nonionic systems, whereas it is weak in the case of similarly charged surfactants. The influence of counterion valence in the formation of mixed micelles was investigated, and results suggest that in similarly charged surfactant mixtures, the degree of counterion binding does have a major role in deciding the extent of interactions. Salt addition reveals a weakening of interactions in ionic-nonionic systems, and this is attributed to head group charge neutralization and dehydration of the ethylene oxide units of the nonionic surfactants. Cloud point and viscosity data on these systems support the observation.Paper no. S1110 in JSD 2, 213-221 (April 1999). KEY WORDS:Cloud point, mixed micelles, sphere-to-rod transitions, synergism.Adsorption characteristics of surfactants from solution onto different interfaces and the propensity of surfactants to form micelles and mesomorphic phases are useful in almost all practical applications such as foaming, dispersing, solubilizing, wetting, emulsifying and cleansing action (1,2). Owing to their improved action over single pure surfactants, mixed systems like surfactant/surfactant (3,4) or polymer/surfactant (5) are often used in formulations of finished products. It is therefore important to investigate the nature of interactions and factors affecting them in aqueous media so as to understand how these control the product performance. The tendency of different surfactants to form mixed micelles is governed by their attractive (synergistic) or repulsive (antagonistic) interactions and is often explained from the β parameter estimated using Rubingh ' s regular solution theory (6). Extensive studies have been carried out on various mixed surfactant systems like anionic-anionic (7-9), cationic-cationic (10-12), anionic-nonionic (13-15), cationic-nonionic (16,17), cationicanionic (18,19), and nonionic-nonionic (20). Considerable interaction has been reported for ionic-nonionic systems, whereas weak or negligible interaction has been observed for similarly charged surfactants. Interaction between anionic-cationic surfactants is generally very strong but such systems often lead to precipitation/coacervation as a result of the coulombic interactions between oppositely charged species. We report in this paper tensiometric studies on eight mixed systems where results are explained in terms of the β parameter. Critical micelle concentration (CMC) data for some anionic-anionic and cationic-cationic systems from the literature (11,12) are analyzed to compute a β parameter so as to investigate the role of counterion valence in the nature and strength of inte...

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Chemical shift changes on micellization of linear alkyl benzenesulfonate and oleate

Cited by 35 publications

References 1 publication

Solubilization Site of Organic Perfume Molecules in Sodium Dodecyl Sulfate Micelles: New Insights from Proton NMR Studies

Solubilization Site of Organic Perfume Molecules in Sodium Dodecyl Sulfate Micelles: New Insights from Proton NMR Studies

Unusual, pH-Induced, Self-Assembly Of Sophorolipid Biosurfactants

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

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