Surface and thermodynamic study of micellization of non ionic surfactant/diblock copolymer system as revealed by surface tension and conductivity

Surface physico-chemical and thermodynamic properties of non ionic surfactants (tween 20 and tween 80) with diblock copolymer poly (oxyethylene/oxybutylene) (e39b19) at 298 k have been investigated by surface tension and conductivity techniques. the surface tensiometery were used to study the critical micelle concentration (cmc),surface excess concentration (γ),minimum area per molecule (a),free energy of micellization (δgm) and free energy of adsorption (δgads). from the observed surface properties it was concluded that the process of micellization is spontaneous and exothermic. conductometry technique was used to determine critical micelle concentration (cmc),degree of ionization (α),degree of counter ion binding (β). the addition of diblock copolymer to the surfactant solutions increase the values of degree of ionization (α),degree of counter ion binding (β). although it led to decrease in the values of cmc indicating that the process of micellization is more favorable and spontaneous. © 2017,university of mohammed premier oujda morocco.