Abstract

Interaction between amphiphiles and water molecules in micelle or bilayer structure has been investigated using aqueous colloids of various amphilphies. The water molecule is not necessarily bound in the fully developed micelle or bilayer (rod-like or lamella) structure which induces the high viscosity or high rigidity of the colloidal system. On the other hand, the water molecule is bound in the micelle colloids of amphoteric amphiphiles or amphiphiles whose molecular assembly creates a realtively strong electrostatic field.Micelle structure of a nonionic amphiphile (n-dodecyl octa (oxyethylene glycol) monoether), which has a weak interaction with water molecules, has been investigated. The spherical micelles having a radius of 28-31 Å remain in a wide concentration range from very dilute to ca. 42wt%. In the concentrated colloids in the isotropic (L1) phase, the spherical micelles are arranged in a certain ordered structure, and the isotropic and the ordered phases are likely to coexist. However, even at such a high concentration as 30wt%, the colloid system shows Newtonian flow.The specific inner surface Os of the spherical micelle in the L1 phase is ca. 0.2Å-1 and this value is approximately twice as large as that of a smooth sphere. Electron density profile is relatively sharp at the interface between the micelle and the medium, regardless of the existence of some bound water. A new micelle model is proposed.

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