Abstract
Electric properties of mixed anionic-nonionic surfactant systems in aqueous solutions above the cmc have been studied in term of pNa values, electrical conductivities, and dielectric constants; these systems were sodium 3, 6, 9-trioxaicosanoate (ECL) -hexadecyl poly (oxyethylene) ethers (POEn, n=10, 20, 30, and 40). The degree of ionic dissociation of mixed micelle decreases with increasing the number of oxyethylene groups in the nonionic surfactant. The electrical conductivity decreases with increasing the number of oxyethylene groups in the nonionic surfactant, in spite of the decrease of activation energy for conduction. The sizes of mixed micelles also decrease. This may be attributed to the fact that an ideally mixed micelle is easier to form for a nonionic surfactant including shorter poly (oxyethylene) chains than for that including longer poly (oxyethylene) chains.
