Binding of sodium dodecyl sulfate (SDS) to the ABA block copolymer pluronic F127 (EO97PO69EO97): F127 aggregation induced by SDS

It has been established that sodium dodecyl sulfate (SDS) binds to the mice lles and monomers of the block copolymer F127. SDS binds to the monomeric u nassociated F127 in the form of polymer/bound SDS micellar complexes. SDS b inds to F127 micelles first forming mixed micelles, which dissociate into s maller mixed aggregates and then to single F127 unassociated monomers. A th ird interaction of SDS, which involves promotion of F127 micelles at concen trations up to 3 degreesC below the critical micellar temperature of pure F 127, was identified ana is investigated in the present work. The formation of such SDS-induced mixed micelles was monitored using differential scannin g calorimetry, light scattering, isothermal titration calorimetry, and a SD S selective electrode for electromotive force measurements. These investiga tions have shown how the different binding and aggregation processes betwee n SDS and F127 involving induced micellization, growth of mixed micelles, b reakdown of mixed micelles, and binding of SD'S to monomeric F127 can be id entified and characterized.