Abstract:

In this paper, the interaction between a dendrimer, composed of G1 (generation 1.0) poly(amidoamine) (PAMAM) and branched with poly(propylene oxide) (PPO)-poly(ethylene oxide) (PEO), and sodium dodecyl sulfate (SDS) was investigated by turbidity titration, dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Interestingly, at low concentrations of added SDS far from the critical micelle concentration (cmc), the system with the dendrimer at 1%(mass fraction) exhibited higher turbidity, indicating that the aggregates grew larger and this was confirmed by DLS, TEM, and AFM. It is mainly due to the strong interaction between the dendrimer and the SDS molecules, as well as the formation of a dendrimer-SDS complex. With a SDS concentration of more than 0.1 mmol·L-1 (about 1%of the cmc), the variation of turbidity value was not obvious mainly because the aggregate size tended to be constant observed from DLS, TEM, and AFM. As the concentration increased further (0.25 and 0.5 mol·L-1), self-aggregation of the SDS molecules or aggregation of the monomolecular dendrimer that interacted with the multimolecular SDS occurred in the system.

Key words: Aggregation behavior, Dendrimer, Turbidity, Interaction, Sodiumdodecyl sulfate