Study of AOT-stabilized microemulsions of formamide and n-methylformamide dispersed in n-heptane

A wide investigation of some physicochemical properties (density, viscosity, conductance, IR spectra, permittivity) of AOT-stabilized dispersions of formamide and n-methylformamide in n-heptane has been performed. The experimental data are consistent with the hypothesis that these highly hydrophilic substances are encapsulated within AOT reversed micelles and that this structure is maintained for both systems well above the volume fraction of the dispersed phase where a percolative transition occurs. In addition, the observed properties of these microemulsions reveal the pivotal role of intermicellar attractive interactions in driving the percolative transition. A marked modification of the structural and dynamical properties of formamide and n-methylformamide accompanying their solubilization within AOT reversed micelles has also been observed. (C) 1997 Elsevier Science S.A.