Alkanediyl-.alpha.,.omega.-bis(dimethylalkylammonium bromide) surfactants. 1. Effect of the spacer chain length on the critical micelle concentration and micelle ionization degree

Zana, R.; Benrraou, Mohamed; Rueff, Roger M.

doi:10.1021/la00054a008

Cited by 1,060 publications

(940 citation statements)

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“…Quaternary ammonium bromides including dodecyltriethylammonium bromide (DEAB), dodecyltributylammonium bromide (DBAB) were prepared by the reaction of corresponding alkyl bromide and trialkylamine. Gemini surfactant dimethylene-1,2-bis(dodecyldimethylammonium bromide), abbreviated as 12-2-12, was synthesized according to the literature method [29]. All the synthesized surfactants were recrystallized five times from mixed solvents of acetone-ether or ethanol-ethyl acetate.…”

Section: Reagents and Materialsmentioning

confidence: 99%

“…The long lifetime of the Gemini surfactant micelles prolongs the whole process of motion-collision exchange ( ex ) between different nanodomains, even equal or greater to the characteristic chemical reaction time ( r ). Thus, the [29,52], the micelle concentration of Gemini surfactant was larger than those of conventional surfactant, thus increasing the probability of effective collisions for material exchange, which is also beneficial to the formation of Fe 3 O 4 nanoparticles.…”

Section: Fe Mössbauer Characterizationmentioning

confidence: 99%

See 1 more Smart Citation

Surfactant effects on the microstructures of Fe3O4 nanoparticles synthesized by microemulsion method

Wang

Yin

et al. 2013

Colloids and Surfaces A: Physicochemical and Engineering Aspect

104

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Section: Reagents and Materialsmentioning

confidence: 99%

Section: Fe Mössbauer Characterizationmentioning

confidence: 99%

Surfactant effects on the microstructures of Fe3O4 nanoparticles synthesized by microemulsion method

Wang

Yin

et al. 2013

Colloids and Surfaces A: Physicochemical and Engineering Aspect

104

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“…In particular, gemini surfactants have critical micelle concentrations (CMC) that are up to two orders-of-magnitude lower than the CMCs of corresponding single chain surfactants [7]. DTAB (dodecyl trimethyl ammonium bromide) can be considered the monomeric form of the C 12 series of gemini surfactants, and has a CMC of 1.5-1.6×10 − 2 M [4,8]. The gemini surfactant, 12-3-12,2 Br − , has a CMC value of 9.1 -9.6× 10 − 4 M [8,9].…”

Section: Introductionmentioning

confidence: 99%

Micelle formation and CMC of gemini surfactants: a thermodynamic model

Camesano

Nagarajan

2000

Colloids and Surfaces A: Physicochemical and Engineering Aspect

143

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Gemini surfactants possess a structure resembling a pair of conventional single chain surfactants covalently connected by a spacer. The spacer can vary in length and chemical structure. In this paper, the aggregation behavior of gemini surfactants is examined on the basis of a free energy model developed by extending our theory for conventional surfactants. Free energy contributions beyond those considered for conventional surfactants arise because of the spacer. They originate from the fact that (a) the spacer shields the hydrophobic core of the aggregate from contact with water, (b) the spacer constrains the distance between the head groups, thus imposing non-uniformity in charge distribution at the aggregate surface, (c) the spacer prevents the two linked tails from having a packing conformation inside the micelle identical to that of analogous unlinked single chain surfactants, and (d) the spacer can be partially buried inside the micelle core provided its length and the molecular interactions allow it. Illustrative calculations for gemini surfactants with tail lengths of 5 -16 carbon atoms and various spacers are discussed here. The spacers considered include the polymethylene chain and a combination of polymethylene chain with NCH 3 , O, S, and aromatic groups. The predicted critical micelle concentration (CMC), micelle aggregation number, sphere-to-rod transition parameter (K) and shape of aggregates are compared with available experimental data. A comparative analysis of the magnitude and shape dependence of the individual contributions to the free energy shows that the nonuniform charge distribution at the aggregate surface and the additional packing constraint on the tails, both originating from the short length of the spacer, play a central role in determining the equilibrium shape of the aggregates.

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“…Recently, a new class (type) of surfactants, named dimeric [1] or gemini [2] have been prepared. They have 2 hydrophobic chains, 2 hydrophilic groups, and a spacer (flexible or rigid) keeping away the two polar groups.…”

Section: Introductionmentioning

confidence: 99%