Scaling laws for some physical properties of the L<sub>3</sub> (sponge)  
phase

Porte, G.; Delsanti, M.; Billard, Isabelle; Skouri, M.; Appell, J.; Marignan, J.; Debeauvais, F.

doi:10.1051/jp2:1991207

Cited by 71 publications

(67 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Reversibility can be checked by comparing light scattering before and after heating above the chain-melting temperature, because a sample containing only surfactants in the molten state scatters light several orders of magnitude less than when chains are in the frozen state (30). For the amphiphilic ion pair chosen here, chains melt well above room temperature (60°C), ensuring easy melting into the liquid state and thus reversibility of self-assembly (17). For nanodiscs and icosahedra, temperature cycling allows us to switch back and forth between molten and frozen states (see details in Comparison with Bicelles in Supporting Text).…”

Section: Discussionmentioning

confidence: 99%

Shape control through molecular segregation in giant surfactant aggregates

Dubois

Lizunov

Meister

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

133

228

View full text Add to dashboard Cite

Mixtures of cationic and anionic surfactants crystallized at various ratios in the absence of added salt form micrometer-sized colloids. Here, we propose and test a general mechanism explaining how this ratio controls the shape of the resulting colloidal structure, which can vary from nanodiscs to punctured planes; during cocrystallization, excess (nonstoichiometric) surfactant accumulates on edges or pores rather than being incorporated into crystalline bilayers. Molecular segregation then produces a sequence of shapes controlled by the initial mole ratio only. Using freezefracture electron microscopy, we identified three of these states and their corresponding coexistence regimes. Fluorescence confocal microscopy directly showed the segregation of anionic and cationic components within the aggregate. The observed shapes are consistently reproduced upon thermal cycling, demonstrating that the icosahedral shape corresponds to the existence of a local minimum of bending energy for facetted icosahedra when the optimal amount of excess segregated material is present.C ontrolling both size and shape of colloidal particles is a major challenge to the predictable formulation of mixed systems consisting of surfactants, polymers, and inorganic solids. Successful control of size and shape requires simultaneous knowledge of the mixture's equilibrium phase behavior and the mechanism of formation. The aim of this article is to describe and test hypotheses based on bending energy to control a general sequence of colloidal shapes, from large discs to punctured planes.If the elemental building blocks of a complex colloidal aggregate are amphiphilic molecules, the basic concept used to rationalize self-assembly is the concept of spontaneous curvature originating from the surface-to-volume ratio of the surfactant film (1). Common single-chain ionic amphiphiles have a spontaneous radius of curvature equivalent to one surfactant length (2) and therefore form globular micelles. Decreasing monolayer curvature obtained by mixing surfactants first produces giant cylindrical and finally locally flat bilayers.When the elementary building block is a fragment of a bilayer, line tension of pores, or rims of discs, and elastic energy associated to dihedral angles on the contact line between adjacent facets need to be considered (3). The crystallization͞ segregation should be consistent with the sequence of shapes observed with strongly interacting charged colloids in the absence of salt. Molecular segregation is demonstrated by specificity of labeling with a dye and direct observation, and we show finally that the resulting shapes correspond to local minima of energy of formation. Mechanism of Shape Control Through Molecular SegregationConsider an initial state of the dispersion with unilamellar vesicles in the fluid state. In the fluid state of mixed vesicles, the two components exhibit in-plane miscibility.Y Upon cooling, nucleation and growth of planar crystals occur in the form of polygonal frozen bilayers, which can only form at a fixe...

show abstract

Section: Discussionmentioning

confidence: 99%

Shape control through molecular segregation in giant surfactant aggregates

Dubois

Lizunov

Meister

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

133

228

View full text Add to dashboard Cite

show abstract

“…(a) Short times ( r : According to Porte et al [16], there are two contributions to the shear birefringence in B fl , one intrinsic and the other one due to the shape anisotropy, as follows:…”

Section: Maurice Klemanmentioning

confidence: 99%

“…In the sponge phase scaling regime [16], i.e. in the limit of infinite dilution, the relaxation time ( r of…”

Section: Maurice Klemanmentioning

confidence: 99%

See 1 more Smart Citation

The lamellar and sponge phases of dilute surfactant systems: Structures and defects at equilibrium and under shear

Kléman¹

1999

Pramana - J Phys

View full text Add to dashboard Cite

show abstract

“…Such configurations are called L 3 phases or sponge phases. 10 The L 3 phase often coexists with a lamellar phase or a highly dilute surfactant solution, or both. In addition to the general structure, sponge phases share many properties with symmetric oil-water microemulsions, including vanishing interface tension and spontaneous curvature.…”

Section: Introductionmentioning

confidence: 99%

Scattering intensity of bicontinuous microemulsions and sponge phases

Peltomäki

Gompper

Kroll

2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

Monte Carlo simulations of dynamically triangulated surfaces of variable topology are used to investigate the scattering intensities of bicontinuous microemulsions. The bulk scattering intensity is shown to follow the Teubner-Strey expression. The domain size and the correlation length are extracted from the scattering peaks as a function of the bending rigidity, saddle-splay modulus, and surfactant density. The results are compared to earlier theories based on Ginzburg-Landau and Gaussian random field models. The ratio of the two length scales is shown to be well described by a linear combination of logarithmically renormalized bending rigidity and saddle-splay modulus with universal prefactors. This is in contrast to earlier theoretical predictions in which the scattering intensity is independent of the saddle-splay modulus. The equation of state, and the asymptotics of the bulk and film scattering intensities for high and low wave vectors are determined from simulations and compared with theoretical results.

show abstract

Scaling laws for some physical properties of the L₃ (sponge) phase

Cited by 71 publications

References 0 publications

Shape control through molecular segregation in giant surfactant aggregates

Shape control through molecular segregation in giant surfactant aggregates

The lamellar and sponge phases of dilute surfactant systems: Structures and defects at equilibrium and under shear

Scattering intensity of bicontinuous microemulsions and sponge phases

Contact Info

Product

Resources

About

Scaling laws for some physical properties of the L3 (sponge) phase

Cited by 71 publications

References 0 publications

Shape control through molecular segregation in giant surfactant aggregates

Shape control through molecular segregation in giant surfactant aggregates

The lamellar and sponge phases of dilute surfactant systems: Structures and defects at equilibrium and under shear

Scattering intensity of bicontinuous microemulsions and sponge phases

Contact Info

Product

Resources

About

Scaling laws for some physical properties of the L₃ (sponge) phase