EFFECTS OF BETA-CYCLODEXTRIN SURFACTANT COMPLEX-FORMATION ON THE SURFACTANT MONOMER-MICELLE EXCHANGE-RATE IN AQUEOUS-SOLUTIONS OF SODIUM PERFLUOROOCTANOATE AND BETA-CYCLODEXTRIN

Solutions of sodium perfluorooctanoate (SPFO) and beta-cyclodextrin (b eta-CD) were studied using ultrasonic relaxation (0.8-190 MHz), speed of sound, and electrical conductivity techniques. The observed relaxat ion processes are believed to be due to the surfactant monomer-micelle exchange process and the molecular dynamics of the beta-cyclodextrin/ surfactant complex. The surfactant monomer-micelle exchange process wa s analyzed using the Aniansson model after the sound absorption due to the presence of the cyclodextrin/ surfactant complex was substracted from the total sound absorption. The resulting data show a single rela xation process indicating that the kinetics of the monomer-micelle exc hange process for the SPFO micelles is relatively unaffected by the pr esence of beta-CD or the 1:1 inclusion complex. Any contribution of co unterion binding to beta-CD or of a fast counterion exchange process a ppears to affect only the micelle distribution and not the mean aggreg ation number, the exit rate for the monomer, or the average volume cha nge associated with the exchange. Furthermore, the presence of the gue st molecule, SPFO, appears to induce ultrasonic relaxation processes w hich are related to the beta-cyclodextrin structure and are normally a bsent in solutions containing only beta-CD.