Statics and dynamics of worm-like surfactant micelles

Cates, Michael E.; Candau, S. J.

doi:10.1088/0953-8984/2/33/001

Cited by 1,299 publications

(2,019 citation statements)

References 57 publications

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“…For T ≥ 0.1, i.e. before the onset of branching, we expect the chain length distribution to be well described by a Flory-Huggins (mean field) type of theory [46,47], and hence that at relatively low volume fractions the chain length follows an exponential law p(l) ∼ exp[−l/ l ], with an average l that increases with lowering the temperature or increasing the density as l ∼ exp[E/(2T )]φ y , in which E is the scission energy of a chain and y ≈ 0.6. Our data is compatible with the expected dependence on both the temperature (left inset of Fig.…”

Section: Self-assembly Spatial Correlations and Network Structurementioning

confidence: 99%

Self-assembly and cooperative dynamics of a model colloidal gel network

Colombo

Gado

2014

Soft Matter

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We study the assembly into a gel network of colloidal particles, via effective interactions that yield local rigidity and make dilute network structures mechanically stable. The self-assembly process can be described by a Flory-Huggins theory, until a network of chains forms, whose mesh size is on the order of, or smaller than, the persistence length of the chains. The localization of the particles in the network, akin to some extent to caging in dense glasses, is determined by the network topology, and the network restructuring, which takes place via bond breaking and recombination, is characterized by highly cooperative dynamics. We use N V E and N V T Molecular Dynamics as well as Langevin Dynamics and find a qualitatively similar time dependence of time correlations and of the dynamical susceptibility of the restructuring gel. This confirms that the cooperative dynamics emerge from the mesoscale organization of the network.

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Section: Self-assembly Spatial Correlations and Network Structurementioning

confidence: 99%

Self-assembly and cooperative dynamics of a model colloidal gel network

Colombo

Gado

2014

Soft Matter

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“…The usual picture of a semi-dilute polymer solution is an assembly of ideal chains made of blobs of size χ. Using this approach, Cates and Candau [2] and later J.P. Wittmer et al [13] derived the relevant equilibrium polymer size distribution. In this subsection, we adapt their derivation to the theoretical framework presented above.…”

Section: The Semi-dilute Casementioning

confidence: 99%

“…It is well known and schematically illustrated in figure 1.1 that some surfactant molecules in solution can self-assemble and form wormlike micelles [2].…”

Section: Introductionmentioning

confidence: 99%

“…Such micellar solutions exhibit fascinating rheological behaviour, such as shearbanding [3], shear-thickenning [4], Maxwell fluid behaviour [2] or anomalous diffusion (Levy flight) [5]. Self-assembled stacks of discotic molecules and chains of bifunctional molecules are other examples of supramolecular polymers.…”

Section: Introductionmentioning

confidence: 99%

“…Our model does not allow for cyclic structures and hence, we simplify the computational load and, more importantly, the theoretical interpretation of the static and dynamical properties of our samples. Anyway, for cylindrical micelles, cyclic structures are expected to exist in very low concentrations [2].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reaction Kinetics of Coarse-Grained Equilibrium Polymers: A Brownian Dynamics Study

Huang

Crevel

et al.

Computer Simulations in Condensed Matter Systems: From Materials to Chemical Biology Volume 2

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Self-assembled linear structures like giant cylindrical micelles or discotic molecules in solution stacked in flexible columns are systems reminiscent of polydisperse polymer solutions, ranging from dilute to concentrated solutions as the overall monomer density and/or the chain length increases. These supramolecular polymers have an equilibrium length distribution, the result of a competition between the random breakage of chains and the fusion of chains to generate longer ones. This scissionrecombination mechanism is believed to be responsible of some peculiar dynamical properties like the Maxwell fluid rheological character for entangled micelles. Simulations employing simple mesoscopic models provide a powerful approach to test mean-field theories or scaling approaches which have been proposed to rationalize the structural and kinetic properties of these soft matter systems. In the present work, we review the basic theoretical concepts of these "equilibrium polymers" and some of the important results obtained by simulation approaches. We propose a new version of a mesoscopic model in continuous space based on the bead and FENE spring polymer model which is treated by Brownian Dynamics and Monte-Carlo binding/unbinding reversible changes for adjacent monomers in space, characterized by an attempt frequency parameter ω. For a dilute and a moderately semi-dilute state-points which both correspond to dynamically unentangled regimes, the dynamic properties are found to depend upon ω through the effective life time τ b of the average size chain which, in turn, yields the kinetic reaction coefficients of the mean-field kinetic model proposed by Cates. Simple kinetic theories seem to work for times t ≥ τ b while at shorter time, strong dynamical correlation effects are observed. Other dynamical properties like the overall monomer diffusion and the mobility of reactive end-monomers are also investigated.

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Linear aggregation revisited: Rods, rings and worms

Schoot

Wittmer²

1999

Macromol. Theory Simul.

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The problem of ring formation in solutions of cylindrical micelles is reinvestigated theoretically, taking into account a finite bending rigidity of the self-assembled linear objects. Transitions between three regimes are found when the scission energy is sufficiently large. At very low densities only spherical and very short, rod-like micelles form. Beyond a critical density, mainly rings but also worm-like chains appear in (virtually) fixed relative amounts. Above a second transition both the length of the linear chains and the relative amount of material taken up by them increase rapidly with increasing concentration. The mass accumulated into long, semi-flexible worms then overwhelms that in rings. The ring-dominated regime is very narrow for semi-flexible chains, confirming that the presence of rings may be difficult to observe in many micellar systems, and indeed disappears completely for sufficiently low scission energy and/or large persistence length.

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Statics and dynamics of worm-like surfactant micelles

Cited by 1,299 publications

References 57 publications

Self-assembly and cooperative dynamics of a model colloidal gel network

Self-assembly and cooperative dynamics of a model colloidal gel network

Reaction Kinetics of Coarse-Grained Equilibrium Polymers: A Brownian Dynamics Study

Linear aggregation revisited: Rods, rings and worms

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