Surface properties of bolaamphiphiles in ethanol/water mixed solutions

The effect of ethanol on the surface properties of bolaamphiphiles and their mixed systems with oppositely charged conventional surfactants is studied and compared with the corresponding conventional surfactant systems. It is found that both the bolaamphiphile and the conventional surfactant have the similar variation tendency of γcmc and Γ∞ in the single surfactant system. However, in the cationic and anionic mixed surfactants system the γcmc decreases with the ethanol addition in the bolaamphiphile systems. This tendency is reverse to that in conventional surfactant system. Surface activity of the asymmetric bolaamphiphiles SHMC decreases greatly when ethanol is added into the system due to the existence of the hydroxyl group in the SHMC molecule. Adding opposite charged surfactant may greatly increase surface activity in the SHMC/C12NEt3Br/ethanol systems.