Dynamics of percolation and energetics of clustering of water/AOT/isooctane microemulsions in the presence of propylene glycol and its oligomers

The temperature-induced percolation of water/AOT/isooctane microemulsion systems has been studied at different concentrations of AOT in the presence of varying concentrations of mono-, di-, and tri-propylene glycols employing conductometric technique. Volume-induced percolation of these microemulsion systems as a function of temperature has also been studied using the same method. The volume-induced percolation data has been analyzed to find the threshold percolation volume fraction. The performance of the scaling equation for volume-induced percolation was tested. The results from temperature-induced percolations have been analyzed to quantify the threshold percolation temperature, performance of the scaling equation, the activation energy for the percolation process, and the thermodynamic parameters of clustering of the dispersed nanodroplets. A simple structural model has been applied in the calculation of the various parameters, i.e. aggregation number (n), core radius (rn), surface number density of the surfactant molecules at the interface (αs), and the number of droplets per unit volume. The structural parameters were rationalized in terms of the percolation temperatures for the microemulsion systems under investigation.