Mixed Micelles of Dodecyltrimethylammonium Bromide and Didodecyldimethylammonium Bromide

Lusvardi, K. M.; Full, A. P.; Kaler, Eric W.

doi:10.1021/la00002a021

Cited by 45 publications

(51 citation statements)

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“…At still higher DDAB there is again evidence for the presence of larger structures coexisting with micelles, consistent with the reported formation of vesicles by pure DDAB in EAN. [3] This means that here one can tune continuously the aggregate structure by the mixing ratio of the two cationic surfactants (in a similar fashion as observed in water for DDAB addition to dodecyltrimethylammonium bromide [82]). Here it is particularly noteworthy that one can enhance the aggregate size substantially in these mixtures, while typically self-assembly in ILs leads to rather small micellar aggregates.…”

Section: Single Component Systemsmentioning

confidence: 85%

“…A) alkylpyridinium halides + SDS/SDBS, B) TDPCl + tetradecanol or DDAB Controlling Morphology through Alkyl Chain Packing It has long been known that self-assembly structure can also be altered by mixing conventional surfactants with cosurfactants [81] such as aliphatic alcohols or bilayer-forming, double chained surfactants. [82] Whereas the catanionic effect in aqueous solution is primarily due to decreasing the effective area per molecule, a0, through electrostatics, chain-packing increases the effective non-polar chain volume, v, with the same net effect of increasing the surfactant packing parameter, v/a0lc, and favouring cylindrical or bilayer-based structures over spherical micelles. As chain-packing effects are expected to be insensitive to solvent ionic strength, we have examined the effects of tetradecanol and didodecyldimethylammonium bromide (DDAB) on micelle formation and structure of TDPCl in EAN.…”

Section: Single Component Systemsmentioning

confidence: 99%

See 1 more Smart Citation

Catanionic and chain-packing effects on surfactant self-assembly in the ionic liquid ethylammonium nitrate

Bryant

Jafta

Gradzielski

et al. 2019

Journal of Colloid and Interface Science

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Micelle formation, particularly the formation of compact, globular micelles in the high ionic strength environment of an ionic liquid, seems to be at odds with the principle of opposing forces and the concept of the surfactant packing parameter. Here we examine how interactions between polar headgroups, with solvent ions, and chain packing affect self-assembly structure in ionic liquids. ExperimentsThe self-assembly of pure cationic and anionic surfactants, their catanionic mixtures, and the effect of the cosurfactant tetradecanol in the ionic liquid ethylammonium nitrate (EAN) is investigated by small-angle neutron scattering (SANS). FindingsThe critical micelle concentrations of cationic surfactants are much higher and micelles much smaller in EAN than in water, whereas anionic micelles are less dramatically affected. Catanionic surfactant mixtures form small micelles in EAN at all compositions, unlike their counterparts in water which form vesicle dispersions or precipitates near 1:1 mole ratios. This contrasts with the behavior of cationic surfactants when mixed with double-chained analogs or alkanol cosurfactants, which induce micelle growth and shape transitions to rod-like and bilayer aggregates through chain packing effects similar to aqueous systems. This enables the aggregate morphology in the ionic liquid to be controlled through the composition of the surfactant mixtures.

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Section: Single Component Systemsmentioning

confidence: 85%

Section: Single Component Systemsmentioning

confidence: 99%

Catanionic and chain-packing effects on surfactant self-assembly in the ionic liquid ethylammonium nitrate

Bryant

Jafta

Gradzielski

et al. 2019

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

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“…Lusvardi et al 30 have previously investigated mixed micelles formed by DTAB and DDAB with SANS. They were investigating samples in the regime 0 < y < 0.3 at rather high surfactant concentrations (c t ¼ 200 and 400 mM, respectively), i.e.…”

Section: Resultsmentioning

confidence: 99%

The growth of micelles, and the transition to bilayers, in mixtures of a single-chain and a double-chain cationic surfactant investigated with small-angle neutron scattering

Bergström

Skoglund

Danerlöv³

et al. 2011

Soft Matter

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Self-assembly in aqueous mixtures of a single-chain (DTAB) and a double-chain cationic surfactant (DDAB) has been investigated with small-angle neutron scattering (SANS). Small oblate spheroidal micelles formed by DTAB grow with respect to width and length to form mixed ellipsoidal tabletshaped micelles as an increasing fraction of DDAB is admixed into the micelles. The growth behaviour of the micelles is rationalized from the general micelle model in terms of three bending elasticity constants spontaneous curvature (H 0), bending rigidity (k c) and saddle-splay constant (k c). It is found that micelles grow with respect to width, mainly as a result of decreasing k c H 0 , and in the length direction as a result of decreasing k c. The micelles are still rather small, i.e. about 140 A in length, as an abrupt transition to large bilayer aggregates is observed. The micelle-to-bilayer transition is induced by changes in aggregate composition and is observed to occur at a mole fraction of DDAB equal to about x ¼ 0.48 in D 2 O, which is a significantly higher value than previously observed for the same system in H 2 O (x ¼ 0.41). An abrupt micelle-to-bilayer transition is in agreement with predictions from the general micelle model, according to which an abrupt transition from micelles to bilayers is expected to occur at xH 0 ¼ 1/4, where x is the thickness of the self-assembled interface, and we may conclude that H 0 (D 2 O) > H 0 (H 2 O) for the system DDAB/DTAB in absence of added salt. Samples with bilayers are found to be composed of bilayer disks coexisting with vesicles. Disks are found to always predominate over vesicles with mass fractions about 70-90% disks and 10-30% vesicles. Micelles, disks and vesicles are observed to coexist in a few samples close to the micelle-to-bilayer transition.

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“…Less than 1 mol% DDAB is required to completely transform adsorbed DTAB rods into a bilayer on either mica [24] or quartz [43]. Although MEDDAB and DTAB are expected to mix nearly ideally in bulk [44], the composition of the adsorbed layer need not mirror bulk composition. Results obtained for mixed DDAB-containing adsorbed layers suggest that the bilayer-forming component will be enriched at the surface.…”

Section: E 23 and Meddab Mixed Filmsmentioning

confidence: 99%

Laterally nanostructured adsorbed layers of surfactant/surfmer mixtures before and after polymerisation

Schwering

Blom

Warr

2008

Journal of Colloid and Interface Science

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Mixed Micelles of Dodecyltrimethylammonium Bromide and Didodecyldimethylammonium Bromide

Cited by 45 publications

References 0 publications

Catanionic and chain-packing effects on surfactant self-assembly in the ionic liquid ethylammonium nitrate

Catanionic and chain-packing effects on surfactant self-assembly in the ionic liquid ethylammonium nitrate

The growth of micelles, and the transition to bilayers, in mixtures of a single-chain and a double-chain cationic surfactant investigated with small-angle neutron scattering

Laterally nanostructured adsorbed layers of surfactant/surfmer mixtures before and after polymerisation

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