Cationic Fluorocarbon Surfactant Research Articles

Surface properties, aggregation behavior and wettability of the mixed system of fluorocarbon cationic surfactant and hydrocarbon anionic surfactant in dilute solutions

Traditional perfluorooctane sulfonic acid (PFOS) fluorocarbon surfactants endangered human health and environment. Therefore, an environmentally friendly quaternary ammonium cationic fluorocarbon surfactant (PFAS-IEt) was synthesized, and surface activities, aggregation behavior, adsorption properties and wettability of PFAS-IEt/sodium n-octyl sulfate (SOS) mixtures in dilute solutions were systematically investigated. The results demonstrated that PFAS-IEt possessed excellent surface activity in aqueous solution. Surprisingly, its surface tension was only 15.33 mN/m and critical micelle concentration (CMC) was 0.002 mol/L. It could be used as a potential substitute for PFOS. In addition, PFAS-IEt had the good synergistic effect with SOS. The PTFE plate with low surface energy could be completely wetted by the binary compound solution at low concentration (0.04 mol/L) (contact angle was 0°), which was superior to the reported long chain quaternary ammonium non-ionic fluorocarbon surfactants (MN-2C9F19 and EN-2C9F19).

Synthesis and application of cationic fluorocarbon surfactants

In this paper, a series of cationic polyurethane fluorinated surfactants were synthesized using a series of isocyanates, and 1H, 1H, 2H,2H-tridecafluoro-1-octanol, 2-(dimethylamino)ethanol, and iodomethane as raw materials in a three-step sequential reaction. These fluorinated surfactants exhibited high surface activity and low critical micelle concentration. In addition, these fluorinated surfactants exhibited excellent wetting and emulsification properties at very low concentrations of 0.1 wt%. In addition the cationic polyurethane fluorinated surfactants are compounded into aqueous film-forming foam extinguishing agents, which exhibit excellent fire extinguishing properties. The desirable properties coupled with the simple and green preparation process make this strategy a new way to prepare sustainable alternatives to long fluoroalkyl chain surfactants.

Enhanced Wettability of a PTFE Porous Membrane for a High‐Temperature Stable Lithium‐Ion Battery Separator

AbstractA hydrophobic poly(tetrafluoroethylene) (PTFE) porous membrane was modified into a hydrophilic lithium‐ion battery (LIB) separator with a higher affinity to the electrolyte via the hybrid consisting of a cationic fluorocarbon surfactant (FCS), polyethylenimine (PEI), and tetraethyl orthosilicate (TEOS), which can be in‐situ biomineralized into SiO2 nanoparticles. The obtained PTFE/FCS‐PEI‐SiO2 separator showed a dynamic electrolyte contact angle, which decreased from 50.3° to 0° within 4 s, along with 215 % of electrolyte uptake. The ionic conductivity and the interfacial resistance were 9.12 mS cm−1 and 228.8 Ω, respectively. In addition, the cell equipped with the separator showed a capacity of 163.7 mAh g−1 at a current density of 0.2 C. Notably, the cell with the separator displayed good high‐temperature stability.

Study on aqueous film‐forming foam extinguishing agent based on fluorocarbon cationic–hydrocarbon anionic surfactants mixture system

AbstractFluorocarbon surfactants were the main components of aqueous film‐forming foam extinguishing agents (AFFF). Unfortunately, the widely used fluorocarbon surfactant perfluorooctane sulfonate (PFOS) was limited due to its toxicity, bioaccumulation and biodegradability. In this paper, an environmentally friendly quaternary ammonium cationic fluorocarbon surfactant with high surface activity and simple synthesis route was reported. The surface performance and aggregation behavior of the mixed solution of this fluorocarbon surfactant and sodium n‐octyl sulfate were studied by means of surface tension meter and transmission electron microscope (TEM). The results showed that the synergistic effect of sodium n‐octyl sulfate and this fluorocarbon surfactant was significant, and many vesicles could be observed in the mixed solution with the concentration of 0.1 mol/L under TEM. Subsequently, three environmental friendly AFFF formulations (F‐1, F‐2, F‐3) were designed with the mixture of the fluorocarbon surfactant, sodium n‐octyl sulfate and lauryl betaine BS‐12 as foaming agent. Through its foam performance test, it could be seen that F‐3 showed relatively excellent foam performance. The initial foam height h0 was 70 mm, the 25% drainage time was 315 s, the extinguishing time was 28 s, and the burn‐back time was 720 s. This kind of fire extinguishing agent had the potential of fire protection application.

A waterborne coating for robust superamphiphobic surfaces

Although recent progress has been made in the development of superamphiphobic fabrics, durability has been an obstacle to their wide application in practice. In this work, a robust water-borne superamphiphobic coating was successfully prepared using poly(vinylidene fluoride) (PVDF) latex particles (225 nm) modified with a cationic fluorocarbon surfactant (Zonyl 321) and an fluoroalkylsilane (FAS). It is demonstrated that the superamphiphobic coating could strongly adhere to various substrates (fabric, sponge, wood, and filter paper) to efficiently repel water and hexadecane under harsh environments such as strong ultraviolet (UV) irradiation, abrasion, plasma cleaning, boiling water, and strong acid/base corrosion. Furthermore, this coating could exhibit good thermal healing capability upon thermal annealing. Through a thorough study of the self-assembly structure of the composite PVDF/Zonyl 321/FAS particles, the robust superamphiphobic property was considered to relate to the following reasons. First, PVDF latex particles provided nanoscale roughness and good UV/chemical resistance. Second, cationic Zonyl 321 self-assembled onto negatively charged PVDF latex particles to form a shell structure with inner fluoroalkyl groups protected by the outer positive charges, which could provide strong adhesion to various fabrics. Third, FAS self-assembled into the fluoroalkyl shell and subsequent self-condensed to render a lightly crosslinked structure. After forming a dense coating onto a substrate, further crosslinking via self-condensation of FAS provided robustness for the coating. Subsequent thermal annealing at 130 °C drove the fluoroalkyl side chains to accumulate at the top surface for superamphiphobicity. This understanding of the composite PVDF/Zonyl 321/FAS system will help us design even better superamphiphobic coatings in the future.

Molecular interaction and foaming property of the mixtures of hydrocarbon, fluorocarbon and silicone surfactants

Fluorocarbon surfactants are inevitably involved in industrial applications in combination with hydrocarbon and silicone surfactants, but properties of the ternary mixed system of hydrocarbon, fluorocarbon and silicone surfactants have received little attention, especially foaming ability. In this study, surface activity and aggregation behavior of the ternary mixed system of anionic hydrocarbon (SDS), cationic fluorocarbon (FC-134) and nonionic silicone surfactants (OFX-5211) are studied systematically in order to investigate molecular interaction. Foaming ability of the ternary mixed system is evaluated by Ross-Miles method. Surface activity is characterized by surface tension. Aggregation behavior is obtained by using cryo-transmission electron microscopy (Cryo-TEM). The results show that intense interaction among molecules exists in the ternary surfactant mixture. FC-134 molecules show the interaction with other two surfactant molecules at air/liquid interface and strongest ability to absorb into air/liquid interface. Large vesicles of binary mixture of SDS/OFX-5211 are transformed into irregular micelles upon addition of FC-134. And wormlike micelles of binary mixture of SDS/FC-134 disappeared upon addition of OFX-5211. The foaming ability of the ternary mixtures is higher than that of any of individual surfactant or binary mixtures of surfactants. The intense interaction among molecules promotes the synergistic effect of foaming ability of the ternary mixtures. This study can provide a guidance for the scientific application of hydrocarbon, fluorocarbon and silicone surfactants.

Facile preparation of mesoporous silica vesicles with large surface holes and their protein sequestration

Mesoporous silica vesicles (MSVs) were prepared using a binary mixed-template system. Cetylpyridinium bromide (CTPB) and cationic fluorocarbon surfactant (FC-4) were employed as templates. The mixed-template synthesis led to MSV materials with two different morphologies. The mesopore expansion and template removal were simultaneously achieved by Ca ion-etching. The Ca ion-etching process not only removed the templates but also generated ultra-large pores through partial collapse of several mesopores. Calcined MSV with smaller mesopores showed better adsorption of small lysozyme than did the etched MSV (Ca-MSV). Contrarily, Ca-MSV showed slightly enhanced adsorption abilities for ovalbumin and hemoglobin than did calcined MSV. Ca-MSV was especially good at sequestering large protein, such as bovine serum albumin.

The Impact of In‐situ Fabric Surface Energy on Dehydration of Fabrics

AbstractReducing liquid surface tension is widely used to increase the efficiency of the centrifugal dehydration in textile wet processing. However, increasing the dehydration efficiency by decreasing fabric surface energy is seldom studied. In this work, the impact of in situ fabric surface energy on residual moisture content (RMC) of fabrics in the dehydration processes was investigated. Different types of fluorocarbon surfactants including cationic, anionic, nonionic and amphoteric were adopted as additives in this study. The liquid surface tension and RMC were efficiently decreased when fluorocarbon surfactants were used. Notably, a cationic fluorocarbon surfactant displays similar surface tension but distinct dehydration efficiency. The in situ fabric surface energy was evaluated by measuring the n‐octane contact angle on the cotton fabric surface under the surfactant solution using the captive bubble method. It was found that the cationic fluorocarbon surfactant system gave the lowest fabric surface energy, which was probably because cationic fluorocarbon surfactants are easier to adsorb onto the surface of cotton fabric to form a fluorocarbon layer. The chemical composition (19F, 12C and 16O) analysis of the cotton fabric surface by X‐ray photoelectron spectroscopy confirms the hypothesis.

Facile fabrication of hollow hydridosilica nanoparticles with mesoporous shell and their dual effect in Pd nanoparticles immobilization

Synthesis of hollow hydridosilica nanoparticles with mesoporous shell (HMHNs) employing a mixture of cationic fluorocarbon surfactant (FC-04) and nonionic triblock copolymer surfactant (P123) as template and triethoxysilane as silica precursor is reported. It is found that the content of the FC-04 in the surfactant mixture greatly influences the aggregation state of the FC-04 and P123 surfactant template and therefore influences the morphology of the synthesized hydridosilica nanoparticles. HMHNs can be synthesized with proper amount of FC-04 surfactants due to the formation of FC-04 and P123 complex micelle, where FC-04 surfactant locates at the outer shell and the P123 constructs the inner core. Ascribed to the inherent hydride sites within the HMHNs, facile immobilization of Pd nanoparticles is achieved by using HMHNs as both the reducing agent and scaffold. The lesser processes produce some smaller Pd nanoparticles (2–3nm) within the pore voids and relatively larger Pd nanoparticles (10–15nm) on the outer surfaces of HMHNs. The catalytic hydrogenation of 4-nitrophenol demonstrates that the heterogeneous Pd catalyst is efficient.

Synthesis of tadpole-shaped Au nanoparticles using a Langmuir monolayer of fluorocarbon surfactant

Tadpole-shaped nanoplates, linearly arranged nanoparticles and triangular and hexagonal nanoplates were synthesized under a Langmuir monolayer of a cationic fluorocarbon surfactant, FC-4 (C 3F 7O(CF(CF 3)CF 2O) 2CF(CF 3)CONH(CH 2) 3N +(C 2H 5) 2CH 3I −) through interfacial reduction of AuCl 4 − by formaldehyde gas. Reports about such tadpole-shaped nanoparticles are relatively scarce. The predominantly plate-like particles are mainly nearly perfect triangular and hexagonal nanocrystals, of micrometer scale in diameter. The Au nanoparticles are characterized using transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). The atomically flat planar surfaces of the Au nanoplates correspond to {111} planes and the lateral surfaces are {110} planes. The surface pressure strongly influences the formation of different Au nanostructures. A potential mechanism of such diverse morphologies is also discussed.

Aggregation Behavior of Fluorocarbon and Hydrocarbon Cationic Surfactant Mixtures: A Study of 1H NMR and 19F NMR

The aggregation behavior and the interaction of four mixed systems for a cationic fluorocarbon surfactant, diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMACl), mixing with cationic hydrocarbon surfactants, alkyltrimethylammonium chloride, CnTACl (n=12, 14, 16, and 18; where n=12 is DTACl, n=14 is TTACl, n=16 is CTACl, and n=18 is OTACl), were studied by 1H and 19F NMR in more detail. The results of 19F NMR measurements strongly indicate that in the three mixed systems of DEFUMACl/DTACl, DEFUMACl/TTACl, and DEFUMACl/CTACl at different molar fractions of fluorocarbon surfactant (alphaF=(cDEFUMACl/cDEFUMACl+cCnTACl)), with an increase of the total concentration of fluorocarbon and hydrocarbon surfactants (cT=cF+cH), the mixed micelles at the first break point and the individual DEFUMACl micelles at the second break point form. However, three different types of micelles were determined in DEFUMACl/OTACl mixtures by 19F NMR measurements, OTACl-rich and DEFUMACl-rich mixed micelles and individual DEFUMACl micelles, respectively. The chemical shifts of proton Deltadelta (1H) for -CH3 in the mixed systems of DEFUMACl/CnTACl (n=12, 14, 16, and 18) have different variation trends from the 19F NMR measurements. For the two systems of DEFUACl/DTACl and DEFUMACl/TTACl, the mixed micelles form at the first break point. At the second break point, for lower alpha F values the DTACl-rich and TTACl-rich mixed micelles form with a strong downfield shift and for higher alpha F values DEFUMACl-rich mixed micelles form with a strong upfield. For the other two systems of DEFUMACl/CTACl and DEFUMAC/OTACl, the chemical shifts of proton Deltadelta (1H) of -CH3 increase with an increase of the total concentration of DEFUMACl/CTACl or OTACl, and mixed CH- and CF-surfactant micelles form. At higher total concentration, the greater effect of fluorinated chains of DEFUMACl on CH-chains was obvious, resulting in the strong upfield chemical shifts. In cationic fluorocarbon and hydrocarbon surfactant mixtures, the different kinds of micelles observed by 19F and 1H NMR measurements could be caused by the increase in alkyl chain length of hydrocarbon surfactants with different critical micelle concentrations. Combining two theoretical models for mixing, for the four different chain-length hydrocarbon surfactants studied, one can conclude that the two components of mixtures interact with each other and form mixed micelles in two completely different ways according to their molecular properties and cmc values in a certain range of total concentrations. One is close to an ideal mixing case with the formation of one type of mixed micelles, such as the DEFUMACl/DTACl and DEFUMACl/TTACl systems. The other is a demixing case with the formation of two types of micelles, i.e., fluorocarbon-rich and hydrocarbon-rich mixed micelles, such as DEFUMACl/CTACl and DEFUMACl/OTACl systems. However, as the total concentrations of the mixed systems are high enough, the four systems tend to demix and to form individual micelles of corresponding components due to the initial respective interaction between fluorocarbon and hydrocarbon chains. That is to say, at high total concentration, the individual DEFUMACl micelles in all four systems could form. These results may be primarily directed toward acquiring an understanding of the mechanism of CF-CH mixtures in aqueous solution and secondarily directed toward providing more detailed information on nonideal mixing.

Synthesis of Fluoro-Functionalized Mesoporous Silica and Application to Fluorophilic Separations

Fluorocarbon-functionalized mesoporous silica is synthesized by the co-condensation of tetraalkoxysilane and fluoro-functionalized alkoxysilane precursors using a cationic fluorocarbon surfactant, C6F13C2H2NC5H5Cl (HFOPC) and C8F17C2H2NC5H5Cl (HFDePC), or a traditional hydrocarbon surfactant (C16H33N(CH3)3Br, CTAB) as templates. Fluorocarbon functionalization decreases the silica pore order, pore size, and surface area. The chain length of the fluorocarbon functional precursor and the surfactant template affects the pore order, the materials textural properties, and the fluorocarbon incorporation. Matching a fluorocarbon surfactant with a fluorocarbon functional precursor does not improve functional group incorporation; the incorporation of the perfluoro-octyl functional group is greater in CTAB-templated silica than in HFOPC-templated silica. The application of these mesoporous silica powders to fluorous separations is demonstrated using hydrocarbon and fluorocarbon-tagged anthraquinones. Dye elution thr...

A Cationic Fluorocarbon Surfactant DEFUMACl and Its Mixed Systems with Cationic Surfactants: 19F NMR and Surface Tension Study

A cationic fluorocarbon surfactant system of diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMACl) and both mixed systems of DEFUMACl/cationic dodecyltrimethylammonium chloride (DTACl) and DEFUMACl/cationic Gemini copolymer was investigated by 19F NMR spectroscopy and surface tension measurements. The critical micelle concentration (cmc) of DEFUMACl by 19F NMR is about 3.40 mmol/L, which is completely consistent with that obtained by the surface tension method. The studies of salt and temperature on the cmc values of DEFUMACl suggest that both salt addition and temperature increase decrease the cmc values of DEFUMACl. 19F NMR measurements provide much richer information on both mixed systems. For the DEFUMACl-DTACl system, two break points were observed with increased total surfactant concentration. The first break point means the DEFUMACl and DTACl mixed micelles and the second one implies the individual DEFUMACl micelles. Results of 19F NMR and surface tension measurements for DEFUMACl/cationic Gemini copolymer mixtures show three peculiar break points, corresponding to the critical association concentration (cac) of DEFUMACl, the concentration where cationic Gemini copolymer molecules become saturated by DEFUMACl micelles, and the concentration where DEFUMACl micelles and cationic Gemini copolymer coexist. These peculiar points in the cationic-fluorocarbon and cationic-copolymer systems were first reported by 19F NMR and surface tension measurements. These results should broaden the useful information for a better understanding of the mechanism of interaction and the behavior of surfactant-polymer mixtures.

Functions of fluorosurfactants 1: Surface activities-improved and vesicle formation of the short-tailed chain sulfonate salt mixed with a fluorosurfactant

Surface-activity of a short-tailed chain hydrocarbon surfactant, heptane-1-sulfonic acid sodium salt (C 7SNa), was studied by using surface tension and conductivity measurements, which the surface-activity was improved largely by the addition of small amount of a fluorosurfactant, 1H,1H,2H,2H,3H,3H,4H,4H-heneicosafluorotetradecylpyridinium iodine (HFTPI). The phase behavior and vesicle formation of C–H/C–F surfactant mixtures in aqueous solutions are similar to ones of cationic–anionic surfactant (catanionic) systems. The birefringent, viscoelastic Lα-phase consisting of unilamellar and multilamellar vesicles can be observed, which were determined by freeze-fracture transmission electron microscopy (FF-TEM) images. The rheological properties of Lα-phase samples were measured. 1H and 19F NMR spectra were measured to monitor the information of self-assemblies of C 7SNa and HFTPI in L 1-phase (spherical micelles) and Lα-phase (vesicles). The results show that the C–H micelles and C–F micelles form in aqueous solutions individually. In Lα-phase (vesicles), the interaction between anionic hydrocarbon (C 7SNa) and cationic fluorocarbon (HFTPI) surfactants exist due to the strong electric static interaction of opposite charge head groups.

Fluorinated surfactant templating of vinyl-functionalized nanoporous silica

Ordered nanoporous vinyl-functionalized silica materials are synthesized by the ‘one-pot’ (direct) synthesis method using three cationic fluorinated surfactants (C 6F 13C 2H 4NC 5H 5Cl, C 8F 17C 2H 4NC 5H 5Cl and C 10F 21C 2H 4NC 5H 5Cl) as templates in basic medium under ambient conditions. The materials obtained possess lower degrees of 2D hexagonal closed packed ordering of the pores when compared to CTAB templated materials. Increases in vinyl content lead to reductions in pore size as well as material order. In spite of having smaller pores, bromination experiments suggest that the vinyl groups are more accessible in the fluoro-surfactant templated materials. Although confinement of the vinyl groups to the palisade region of the fluorinated micelle templates may contribute to this increase in accessibility, reduced pore order in the fluorinated templated materials may also improve the accessibility, as observed here for intentionally disordered CTAB-templated materials. Cationic fluorocarbon surfactants not only have the potential to be templating agents, but also present the possibility of re-organizing the alignment of organic functional groups in the pores of organic–inorganic hybrids obtained by direct synthesis.

Ni-fluorinated vapor growth carbon fiber (VGCF) composite films prepared by an electrochemical deposition process

Nickel-fluorinated vapor growth carbon fiber (VGCF) composite films have been fabricated by using electrochemical deposition method from the plating bath containing a cationic fluorocarbon surfactant as the dispersing agent of fluorinated VGCF. The ESCA result confirmed the existence of metallic Ni and the fluorinated VGCF with C–F covalent bond structure in the composite film, while the SEM and TEM results showed that the fluorinated VGCFs embedded into the Ni-fluorinated VGCF composite film obtained from the plating bath at a dispersion concentration of 2.5 g dm −3 VGCF. The results clearly proved that the bath concentration and deposition conditions, which were designed in the present study, are effective on preparing the Ni-fluorinated VGCF composite film.

Electrochemical Preparation and Characterization of Nickel/Ultra-Dispersed PTFE Composite Films from Aqueous Solution

Nickel/ultra-dispersed PTFE composite films with various PTFE content are electrochemically prepared from a Watt’s nickel plating bath in which the PTFE particles (mean diameter 0.3 mm) are suspended using a cationic fluorocarbon surfactant. The microstructures of Ni-PTFE composite films are analyzed by means of XRD, SEM and TEM, and their water-repellencies are also measured. The results indicate that the PTFE particles take a homogeneous distribution within all the composite films. The PTFE particle content in the composite films is dependent upon the particle concentration in the plating bath and the plating parameters, and strongly influence the physical properties of Ni-PTFE composite films such as water-repellency. The contact angle of a water drop on the surface of composite film with maximum PTFE content of about 47.4 vol% reaches 154.9 � , showing a superior water-repellency.

二酸化チタンに形成されたフッ化炭素界面活性剤吸着層への二種類の有機化合物の吸着可溶化

The binary adsolubilization behaviors of 2-naphthol+biphenyl and 2-naphthol+1,3-dichlorobenzene in a cationic fluorocarbon surfactant adsorbed layer formed on TiO 2 have been investigated as a function of pH. In the binary adsolubilization of 2-naphthol+biphenyl, the adsolubilized amount of 2-naphthol increases gradually until pH 7 and then sharply with a further increase of pH, whereas the adsolubilization of biphenyl is not observed in the wide pH region. In the binary adsolubilization of 2-naphthol +1,3-dichlorobenzene, the adsolubilization behavior of 2-naphthol shows a similar trend as that of 2-naphthol+biphenyl system, while the adsolubilized amount of 1,3-dichlorobenzene increases gradually with pH from 3 to 10. The enhancement in the adsolubilization of 2-naphthol at high pH is attributed to the interaction between deprotonated 2-naphthol and the cationic surfactant as well as the increase of interaction between negatively charged TiO 2 and the surfactant. The adsolubilized sites for binary adsolubilization of 2-naphthol+1,3-dichlorobenzene are also discussed from the admicellar partitioning coefficients.

Interactions of fluorocarbon-modified poly(acrylic acid) with a cationic fluorocarbon surfactant

Abstract The physicochemical properties of mixed systems of fluorocarbon-modified poly(acrylic acid) (FA) with a cationic fluorocarbon surfactant, bis(2-hydroxyethyl)(2-hydroxy-3-perfluoro-octylpropyl)methylammonium chloride (DEFUMAC), have been investigated by surface tension, fluorescence, solubility, and 19F NMR spin–lattice relaxation measurements. The result obtained from the surface tension measurement indicates that surface DEFUMAC–FA complexes are formed by strong electrostatic attraction at pH 10, while they are formed by hydrogen bond at pH 4. However, hydrophobic interaction is hardly observed at both pHs. In the bulk properties estimated from fluorescence and solubility measurements, DEFUMAC–FA complexes exhibit large solubility capacity for fluorocarbon compounds when the content of fluorocarbon in FA increases. Moreover, the result obtained from the spin–lattice relaxation time measurement suggests that the mobility of hydrophobic end group of DEFUMAC for DEFUMAC–FA complex at pH 10 is more restricted than that at pH 4.

Rheological and Light Scattering Studies of Cationic Fluorocarbon Surfactant Solutions at Low Ionic Strength

The structural and dynamic properties of low ionic strength micellar solutions of the cationic surfactant perfluorooctylbutane trimethylammonium bromide have been investigated by means of dynamic and static light scattering and rheological experiments. In the range of concentration extending from the critical micelle concentration to about the overlap concentration, the surfactant self-assembles into micellar aggregates with sizes of the order of 100 nm. At higher concentrations, the system is characterized by a single correlation length consistent with the formation of a transient network of wormlike micelles. In the dilute regime, the solutions exhibit a very large shear thickening effect (up to 50) and a very slow recovery (hours) after a thermal or mechanical perturbation. The extent of consistency of the dynamical observations with the various possible structures inferred from the scattering data has been discussed. Some arguments are in favor of the presence of interlinked micellar rings in the quiescent state, which was suggested in a recent theoretical model.