Formation worm-like micelles

PS-PB-PS = 70.10% M, = 101, 14% Ethyl acetate Formation of worm-like micelles from spherical micelles, associated with cloud point Turbidometry, TEM. SLS Canham et at (1980)... 

In this chapter, a brief theoretical background on the rheological behavior of viscoelashc worm-like micelles is given. It is followed by a discussion on the temperature-induced viscosity growth in a water-surfactant binary system of a nonionic fluorinated surfactant at various concentrations. Finally, some recent results on the formation of viscoelastic worm-like micelles in mixed nonionic fluorinated surfactants in an aqueous system are presented. 

Worm-Like Micelles in Diluted Mixed Surfactant Solutions Formation and Rheological Behavior... 

In this chapter, we present a review of the contribuhon of Kunieda s group regarding to worm-like micelles formation, the stmcture and rheological behavior of the miceUar solution, through the use of published and unpublished material of his group. 

Worm-Like Micelles Formation and Rheological Behavior 241... 

Extensive studies have been reported by Kunieda s group regarding the formation of worm-like micelles and micellar transient networks in water-surfactant-cosurfactant systems. However, for applications, it is also relevant to know the effect of additives on systems containing worm-hke micelles. It is reported that oils induce a rod-sphere transition in surfactant micellar solutions, leading to a reduction in viscosity [32]. Kunieda s group studied the solubilization of different oils in wormlike micellar solutions [19, 33]. The amount of solubilized oil, its location within the micelle, and its effect on micellar shape and size demonstrated to strongly depend on the nature of the oil and its interactions with the surfactants. 

To conclude, in this work we present a review and explanation of the main contributions of Professor Kunieda in the field of rheology of worm-like micelles. It can be remarked that his works have extended the number and types of surfactant systems able to present worm-like micelles, on the one hand, and have deepened the elucidation of structure and formation mechanism, on the other hand. 

A remarkable contribution in recent years was to have shown for the first time the formation of highly viscoelastic worm-like micelles (Figure 12) in mixed nonionic surfactant systems [110]. This finding allowed to clarify the relation between packing constraints of hydrophobic chains and micellar growth because the complex interactions between counterions (present in ionic surfactant systems) and headgroups had not to be taken into consideration. 

He showed the formation of viscoelastic worm-like micelles in various nonionic and ionic surfactant systems and described the evolution of micellar growth namely by rheology and small-angle X ray scattering [110, 112, 118, 133, 137, 144—155], Zero-shear viscosities 3 x 10 times that of water was reported for certain systems [118],... 

A., Hattori, K., and Kunieda, H. (2004) Effect of nonionic head group size on the formation of worm-like micelles in mixed nonionic/cationic surfactant aqueous systems. J. Chem. Eng. Soc. Jpn., 37, 622-529. 

The example considered in this section suggests that the size and stability of nanoparticles built by micellization is controlled by two major factors, geometry of the amphiphilic molecules and the interfacial tension between the hydrophobic tails and water. If the shape of the molecules is not suitable for the formation of a spherical micelle, the micelle will not be stable with respect to fluctuations of curvature at constant aggregation number and cyhndrical or worm-like micelles with high polydispersity can be formed. " " ... 

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