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Formation of Alkylbenzenesulphonates in the Aqueous Solutions and in Mixed Media

Lyotropic liquid crystalline phases of alkylbenzenesulphonates (ABS) were prepared either by mixing the surfactant with water or with the solutions of metal-nitrates. The light scattering measurements were used to determine the fractal dimensions, df, from the slopes of the straight lines of log/log plot assuming the power scattering equation, I(Q)ľQ-df. The results can be improved with the Fourier transform taking into consideration the number and particle sizes. The dynamics and structure of such phases formed in the aqueous solutions can be considered as self-similar regarding the processes from the first step of molecular association from the homogeneous solution until the formation of aggregated particles showing the lamellar phase. The lamellar phases of ABS prepared in the water/n-octanol media in the presence of an electrolyte were transformed to an inverse hexagonal phase within a certain range of the mixing ratio at higher temperatures. Cooling of the isotropic phase at high temperature leads first to the separation of an inverse hexagonal phase ; the system shows a transition to the lamellar phase at room temperature within several days. It is possible to follow the kinetics of the dendritic-like growth of the inverse hexagonal phase in the polarization microscope.

Formation ; Alkylbenzenesulphonates ; Mixed Media

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