Time Effect In The Supramolecular Formation Of Cobalt Monooleate In Apolar Solvents

Abstract

Viscometric, transient electric birefringence, and light-scattering intensity and linewidth measurements on cobalt monooleate soap in apolar solvents clearly showed the existence of a time effect in the formation of supramolecular structures in solution. After dissolution, a rapid change in solution properties occurred at the initial stage, then the change slowed down, and finally an asymptotic behavior was observed. The association process for cobalt monosoap in apolar media may be considered as a time-dependent micellization process which requires a very long time, usually hundreds of hours to reach the association-dissociation equilibrium. The OH-bridging mechanism of coordination interactions implies an open-type association process, resulting in a unidimensional growth of soap chains during supramolecular formation. Strong temperature dependence of the time effect suggests that the association process involved is not simply diffusion-controlled. A theoretical model based on an open-type association mechanism is being proposed to account for the polymer solution behavior.