Aggregation of ω-hydroxy quaternary ammonium bolaform surfactants

omega-Hydroxy quaternary ammonium bolaform surfactants form much smaller micelles in solution than the corresponding non-hydroxy (conventional) surfactants. Aggregation numbers for micelles formed by the omega-hydroxy surfactants, determined using H-1 NMR spectroscopy and steady-state fluorescence quenching, are very small (N = 5-18). The micelle size is consistent with aggregates of about half the diameter of a conventional surfactant. This implies that both the quaternary ammonium and the terminal hydroxyl are positioned at the micelle/water interface. The critical micelle concentrations of the bolaform surfactants, determined using H-1 NMR and the conductivity method, are between 3 and 9 times greater than those of the corresponding non-hydroxy surfactants.