Physicochemical Studies on Microemulsions. 8. The Effects of Aromatic Methoxy Hydrotropes on Droplet Clustering and Understanding of the Dynamics of Conductance Percolation in Water/Oil Microemulsion Systems

The temperature-induced dynamic percolation of water/oil (w/o) microemulsions (water/AOT/heptane, water/AOT/octane, and water/AOT/decane) has been studied in the presence of hydrotropes (2-methoxy phenol, 4-methoxy phenol, 5-methoxy resorcinol, and 3-methoxy catechol). The results have been analyzed (1) to estimate the threshold percolation temperature, (2) to test the performance of the scaling equation, (3) to obtain the activation energy for the percolation process, and (4) to assess the thermodynamics of clustering of the dispersed nanodroplets. The influence of substitution of the methoxy group (at different positions of the phenolic moieties) on the process has been compared with their nonmethoxy analogues and analyzed in favor of “fusion−(mass transfer)−fission” mechanism of dynamic percolation. The assessment of role of the hydrophobic chain length of the hydrocarbon oil on the process of percolation has also been attempted.