Interactions between a hydrophobically modified poly(amidoamine)dendrimer and surfactants in aqueous solutions

The interactions between poly(amidoamine)dendrimer(generation,4) with octyl end groups and surfactants such as sodium dodecyl sulfate (SIDS), dodecyltrimethyl ammonium bromide (DTAB), and hexaoxyethylenedodecyl ether (C12E6) in aqueous solutions have been investigated by surface tension, fluorescence spectra of pyrene, and dynamic light scattering measurements. The results of dynamic light scattering and surface tension measurements indicate that the dendrimer molecules are aggregated in the absence and presence of the surfactants and they are adsorbed at the air-water interface, resulting in the remarkable reduction of surface tension of water. From the measurements of pyrene fluorescence spectra it is suggested that the dendrimer-SDS system provides much lower micropolarity environment than those for the dendrimer-DTAB or C12E6 system. The mechanisms for the interactions between the dendrimer and surfactants have been discussed. (C) 2002 Elsevier Science B.V. All rights reserved.