Redox switched transition of vesicles self-assembled from AOT and ferrocene derivative molecules

Vesicles prepared in an aqueous solution through self-assembly of the oxidized form of N,N-dimethyl-aminomethylferrocene (Fc(+)M) and an anionic surfactant, sodium bis(2-ethyl-1-hexyl) sulfosuccinate (AOT), could be reversibly transformed by redox reactions. Adding the hydroquinone as a reducing agent will cause the dissociation of vesicles and change the solution into emulsion. Subsequent oxidzation by adding Ce(SO4)(2) will regenerate vesicles. The vesicle structure and morphology were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively and the mean particle size was about 200 nm. The mechanism of vesicle formation and disruption caused by redox reactions is discussed along with I he data obtained from cyclic voltammetry (CV) and UV-vis spectroscopy measurements. The redox state changes of the ferrocerryl moiety may influence the noncovalent interactions between FcM and AOT. Meanwhile, the pi-pi stacking and amphiphilic hydrophobic association are also included during such a redox modulated process. These results provide guidance for the design of surfactant and small molecular systems that permit active control of self-assembly. (C) 2009 Elsevier B.V. All rights reserved.