Network properties of semidilute aqueous KBr solutions of cetyltrimethylammonium bromide

Candau, S. J.; Hirsch, Ernest; Zana, R.; Adam, M.

doi:10.1016/0021-9797(88)90377-3

Cited by 129 publications

(81 citation statements)

References 39 publications

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“…In the semidilute regime the variation of the zero shear viscosity with C can be satisfactorily described by a power law with an exponent a. Such a behavior was already observed for other micellar systems (9,16,17,30,31). upon increasing salt content is also observed for CTAB solutions ( Figure 6) .…”

Section: Resultssupporting

confidence: 54%

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Rheological behaviour of wormlike micelles : effect of salt content

et al. 1993

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We study the effect of salt content on the rheological properties of wormlike micelles formed from hexadecyltrimethylammonium bromide (CTAB) in presence of potassium bromide (KBr) and of cetylpyridinium chlorate (CPC10,) in presence of sodium chlorate (C10,Na). Upon increasing the salt concentration, at fixed surfactant concentration, we observe for both systems a maximum of the zero-shear viscosity %. For salt concentrations less than that corresponding to the maximum of qO, the variation of qo with the surfactant concentration C can be described by a reptation model. Beyond the maximum, the scaling laws obtained for qo(C) are characterized by values of the exponent much smaller than those predicted by the existing theoretical models. The results are qualitatively interpreted by a description based on a structural evolution upon increasing salt content from a system of entangled linear micelles to a multiconnected network. Measurements of the plateau modulus of CTAB solutions, as a function of KBr, give results supporting the above hypothesis.Nous prtsentons une ttude de l'influence de la teneur en sel sur les propriktks rhwlogiques de solutions de micelles cylindriques form& i partir de bromure d'hexadecyltrimethylammonium (CTAB) en prksence de bromure de potassium (KBr) et de chlorate de cetylpyridinium (CPC10,) en presence de chlorate de sodium (C10,Na). Lorsqu'on fait varier la concentration en sel, i concentration en tensioactif constante, on observe pour les deux syst&mes un maximum de la viscositk h gradient nu1 7,. Pour des concentrations en sel infkrieures i celle correspondant au maximum de qo la variation de qo avec la concentration en tensioactif C peut Ctre d6crite par un modtle de reptation. Au-delh du maximum les lois d76chelles obtenues pour qo(C) sont caractkriskes par des valeurs de l'exposant beaucoup plus faibles que celles praites par les modtles thbriques existants. Les rksultats sont interprttts qualitativement 2 partir d'une description fond& sur l'kvolution de la structure micellaire lorsqu'on augmente la teneur en sel, d'un systkme de micelles lintkires enchev2trks vers un rkseau interconnectk. Les mesures du plateau du module de cisaillement en fonction de la concentration en KBr pour des solutions de CTAB donnent des rksultats ktayant cette hypothbse.Article published online by EDP Sciences and available at http://dx

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Section: Resultssupporting

confidence: 54%

“…This system being strongly viscoelastic, it is possible to measure the stress relaxation. The latter was found to deviate only slightly from the exponential behaviour (31), which ensures that the viscoelastic behaviour is not described by Eq. 9, characteristic of the classical reptation process.…”

Section: Resultsmentioning

confidence: 92%

Rheological behaviour of wormlike micelles : effect of salt content

et al. 1993

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“…We then postulated that the addition of water to lecithin/isooctane solutions induces one-dimensional aggregation of the lecithin molecules into long cylindrical aggregates. Above a crossover lecithin volume fraction, q~*, these micelles entangle and form a network similar to that of semidilute polymer solutions or aqueous solutions of ionic micelles at high enough ionic strength [3,5]. This structural model was strongly supported by QLS and SANS measurements of the concentration dependence of the hydrodynamic and static correlation lengths, ~h and ~s respectively, in the semidilute regime.…”

Section: Introductionmentioning

confidence: 73%

“…( 1) It has been shown by Candau et al, that viscoelastic aqueous micellar solutions, where giant cylindrical and flexible micelles form a transient network, indeed have network properties very similar to classical polymer solutions [5]. However, the situation is more complicated in the case of the rheological properties at low frequencies, in particular for ~s and the viscoelastic relaxation time r. For semidilute polymer solutions in good solvents, de Gennes reptation theory predicts the following scaling law for ~/s [3]: t/s -N 3" ~ b3'75 , (2) where N is the micellar aggregation number.…”

Section: Theorymentioning

confidence: 95%

Viscoelastic properties of polymerlike reverse micelles

1989

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A dramatic increase in the viscosity of reverse micellar solutions of lecithin in a variety of organic solvents of up to a factor of 106 upon the addition of a small amount of water can be observed. The formation of viscoelastic solutions can be explained by a water-induced aggregation of lecithin molecules into flexible cylindrical reverse micelles and the subsequent formation of a transient network of entangled micelles. The viscoelastic properties of these solutions are characterized as a function of water content and temperature for different organic solvents by means of dynamic shear viscosity measurements. The results are interpreted by making analogies to the behavior of semidilute polymer solutions and living polymers.

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“…During the following years, many papers relating the increasing viscosity of the solution composed of surfactant and electrolyte have been published (2)(3)(4)(5)(6)(7)(8). Among them the systems of sodium salicylate (NaSal) and alkyl trimethyl ammonium halides or alkyl pyridinium salts are most extensively studied.…”

Section: Introductionmentioning

confidence: 99%