Active control of surface properties and aggregation behavior in amino acid-based Gemini surfactant systems

Two types of Gemini surfactants containing a disulfide bond in the spacer, sodium dilauroyl cystine (SDLC) and sodium didecamino cystine (SDDC), were synthesized, and their surface properties and aggregation behavior in aqueous solution were studied by means of surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence. During the transition of the Gemini surfactants to their corresponding monomers through the reduction of disulfide bonds, the surface tensions of their aqueous solutions, as well as their aggregation behavior, changed greatly. The reduction of SDLC and SDDC led to disruption of the vesicle, and the oxidation of corresponding monomers to Gemini surfactants led to vesicle re-formation. These results demonstrated the control of surface properties and aggregation behavior by the reversible transition between the Gemini surfactant and its monomer via reduction/oxidation reactions. (C) 2008 Elsevier Inc. All rights reserved.