Aggregation of omega-hydroxy quaternary ammonium bolaform surfactants

omega-Hydroxy quaternary ammonium bolaform surfactants form much smaller mi celles in solution than the corresponding non-hydroxy (conventional) surfac tants. Aggregation numbers for micelles formed by the omega-hydroxy surfact ants, determined using H-1 NMR spectroscopy and steady-state fluorescence q uenching, are very small (N = 5-18). The micelle size is consistent with ag gregates of about half the diameter of a conventional surfactant. This impl ies that both the quaternary ammonium and the terminal hydroxyl are positio ned at the micelle/water interface. The critical micelle concentrations of the bolaform surfactants, determined using H-1 NMR and the conductivity met hod, are between 3 and 9 times greater than those of the corresponding non- hydroxy surfactants.