In this paper, we study the optimal behavior of water-alcane/(alkyl)benzene blend -polyethyoxylated octylphenol systems as a function of the number of ethylene oxide units of the surfactant. We find this behavior highly nonlinear and we partially interpret it by means of a differential fractionation of the surfactant. Remaining gaps from linearity suggest an interfacial oil segregation that we find favorable to polar and small (alkyl)benzene molecules.
