The present study is focused on evaluation of interfacial compositions and thermodynamic properties of w/o mixed surfactant [(sodium dodecylsulfate, SDS/polyoxyethylene (23) lauryl ether, Brij-35)/1-pentanol (Pn)fisopropyl myristate (IPM)] microemulsions under various physicochemical conditions by the dilution method. The number of moles of Pn at the interface (n(a)(1)) and bulk oil (n(a)(0)), and various thermodynamic parameters [viz. standard Gibbs free energy (Delta G(o -> 1)(0)), standard enthalpy (Delta H-o -> 1(0)), and standard entropy (Delta S-o -> 1(0)) of the transfer of Pn from bulk oil to the interface!' have been found to be dependent on the molar ratio of water to surfactant (omega), concentration of Brij-35 (XBrij-35), and temperature. Temperature-insensitive microemulsions with zero specific heat capacity (Delta C-p(0))(0 -> 1) have been formed at specific compositions. The intrinsic enthalpy change of the transfer process(Delta H-0)(0 -> i) has been evaluated from linear correlation between (Delta H-0)(0 -> i) and (Delta H-0)(0 -> i) at different experimental temperatures. The present report also aims at a precise characterization on the basis of molecular interactions between the constituents and provides insight into the nature of the oil/water interfaces of these systems by conductivity and dynamic light scattering studies as a function of omega and XBrij-35. Conductivity studies reveal that incorporation of Brij-35 in non-percolating water/SDS/Pn/IPM systems makes them favorable for omega-induced percolation behavior up to XBrii-35 <= 0.5. But further addition of Brij-35 causes a decrease in conductivity with increasing co. Furthermore, the hydrodynamic diameters of the microemulsion droplets increase with increase in both XBrij-35 and omega. Correlations of the results in terms of the evaluated physicochemical parameters have been attempted. (C) 2013 Elsevier Inc. All rights reserved.