Wormlike Micelles as “Equilibrium Polyelectrolytes”:  Light and Neutron Scattering Experiments

Sommer, Cornelia; Pedersen, Jan Skov; Egelhaaf, Stefan U.; Cannavacciuolo, Luigi; Kohlbrecher, J.; Schurtenberger, Peter

doi:10.1021/la010214+

Cited by 57 publications

(55 citation statements)

References 39 publications

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“…7 against C D , it seemed that the most linear relationship was obtained compared with other plots; this is consistent with d m being related to the inter-wormlike cylinder distance. We observe exactly the same behaviour as reported for polymer-electrolyte and salt free (or lowionic strength) wormlike micelle solutions (Sommer et al, 2002). Cannavacciuolo et al (2002) carried out a Monte Carlo simulation on systems consisting of many charged wormlike micelles with excluded volume and electrostatic interactions and concluded that the scattering function becomes almost identical with that of uncharged system when the ionic strength is more than 0.1 mol l À1 .…”

Section: Structure Factorssupporting

confidence: 83%

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Salt-concentration dependence of the structure and form factors for the wormlike micelle made from a dual surfactant in aqueous solutions

Eguchi

Kaneda²,

Hiwatari³

et al. 2007

J Appl Cryst

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Small-angle X-ray scattering (SAXS) from dual-surfactant aqueous solutions made from sodium lauryl ether sulfate and coconut fatty acid amido propyl betaine was systematically measured as a function of the net sodium cation concentration, [Na + ]*, and the surfactant concentration, C D . The SAXS intensity [I(q)] was normalized to C D and the resultant I(q)/C D was extrapolated to C D = 0 to give a form factor P(q) for each [Na + ]* [where q = 4 sin( /2)/ is the magnitude of the scattering vector, is the wavelength and 2 is the scattering angle]. The low-q behaviour of P(q) was consistent with long rigid cylinders. The middle-and high-q profiles fitted well with a core-shell cylinder model for all [Na + ]*. The core and total radii (R c and R s ) did not depend on [Na + ]* at all: R c = 1.2 AE 0.05 and R s = 3.1 AE 0.05 nm for [Na + ]* = 0.42-1.5 mol l À1 , indicating that the salt concentration changes did not induce any structural changes and reassembling of the surfactants comprising the micelles. This fact is in contrast to the rheological behaviour where the relaxation mode strongly depends on [Na + ]*. The structure factor [S(q)] was obtained by dividing I(q)/C D by P(q) for each C D and the mean distance (d m ) between the micelles was obtained from the first maximum of S(q) versus q plots. The d m value decreased with increasing C D and [Na + ]*, which is in good agreement with the theoretical prediction and experimental results for charged wormlike micelle solutions.

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Section: Structure Factorssupporting

confidence: 83%

“…This is because the electrostatic screening due to added salt is large enough to reduce repulsion between charged micelles. Their model was able to accurately reproduce the structural peak of the scattering function for charged micelles (Sommer et al, 2002). The C D dependence of d m in Fig.…”

Section: Structure Factorsmentioning

confidence: 85%

Salt-concentration dependence of the structure and form factors for the wormlike micelle made from a dual surfactant in aqueous solutions

Eguchi

Kaneda²,

Hiwatari³

et al. 2007

J Appl Cryst

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“…The model was originally developed for studying wormlike micelles,28, 29 and most of the applications published in the literature are related to this type of system. The model has also been used in various modified forms for studying electrostatic interactions in charged wormlike micelles, so‐called equilibrium polyelectrolyte chains 29–33…”

Section: Introductionmentioning

confidence: 99%

Scattering functions of semidilute solutions of polymers in a good solvent

Pedersen

Schurtenberger

2004

J Polym Sci B Polym Phys

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ABSTRACT:Expressions for analyzing small-angle scattering data from semidilute solutions of polymers in a good solvent over a broad range of scattering vectors are examined. Three different scattering function expressions are derived from Monte Carlo simulations. The expressions are similar to those of polymer reference interaction site models, with a scattering-vector-dependent direct correlation function. In the most advanced model, the screening of excluded-volume interactions beyond the overlap concentration is taken into account. Two simpler expressions, in which the screening of excluded-volume interactions is not included, are also applied. The three models are tested against small-angle neutron scattering (SANS) experiments on polystyrene in deuterated toluene for a broad range of molar masses and concentrations over a wide range of scattering vectors. For each model, simultaneous fits to all the measured scattering data are performed. The most advanced model excellently reproduces the SANS data over the full range of the parameters. The two simpler models fit the data almost equally well. On the basis of an extensive study, an optimal fitting strategy can be recommended for experimentalists, who want to analyze small-angle scattering data from polymers at any concentration. For data sets that do not contain data on the single-chain scattering function, the simpler model is recommended; it uses a direct correlation function equal to the form factor of an infinitely thin rod, which is independent of the concentration and molar mass.

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“…Persistence lengths of the order of 400 Å are typical for neutral wormlike micelles, and have been found repeatedly in the recent literature [27,53,98,100,102,107]. For polyelectrolyte micelles, the total persistence length can be larger than the above characteristic values [108,109]. In conclusion, the persistence length of micellar aggregates is of the order of 400 Å, a value that is between that of synthetic polymers [104] and that of biological molecules, such as DNA, actin and tubulin [110,111].…”

Section: Comparison With Small-angle Neutron Scatteringmentioning

confidence: 80%

Rheology of Wormlike Micelles: Equilibrium Properties and Shear Banding Transitions

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We review the experimental and theoretical results obtained during the past decade on the structure and rheology of wormlike micellar solutions. We focus on the linear and nonlinear viscoelasticity and emphasize the analogies with polymers. Based on a comprehensive survey of surfactant systems, the present study shows the existence of standard rheological behaviors for semidilute and concentrated solutions. One feature of this behavior is a shear banding transition associated with a stress plateau in the nonlinear mechanical response. For concentrated solutions, we show that in the plateau region the shear bands are isotropic and nematic.

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Wormlike Micelles as “Equilibrium Polyelectrolytes”: Light and Neutron Scattering Experiments

Cited by 57 publications

References 39 publications

Salt-concentration dependence of the structure and form factors for the wormlike micelle made from a dual surfactant in aqueous solutions

Salt-concentration dependence of the structure and form factors for the wormlike micelle made from a dual surfactant in aqueous solutions

Scattering functions of semidilute solutions of polymers in a good solvent

Rheology of Wormlike Micelles: Equilibrium Properties and Shear Banding Transitions

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