LIGHT-SCATTERING STUDY OF SODIUM DODECYL POLYOXYETHYLENE-2-SULFATE MICELLES IN THE PRESENCE OF MULTIVALENT COUNTERIONS

The properties of ionic micelles of sodium dodecyl polyoxyethylene-2-s ulfate in the presence of multivalent ions were investigated by means of Light scattering methods. It was shown that divalent and especially trivalent counterions may lead to dramatic change in the micellar siz e and shape even at very low ionic strength. This effect is particular ly pronounced for trivalent counterions as Al3+. The persistent length s for some rod-shaped micelles were obtained and the energy of bending of such rods was estimated. The solubilization capacity of sodium dod ecyl polyoxyethylene-2-sulfate was shown to be also dependent on the p resence of divalent and trivalent ions. it increases with varying the counterion valence from one to thr;ee. The increase of the solubulizat ion capacity of anionic surfactants in the presence of divalent and fu rthermore trivalent counterions could be of practical importance since it is directly related to the cleaning action of given detergent comp osition.