A Non-Steroidal Facial Amphiphile

This paper gives the synthesis of an unusual non-steroidal amphiphile consisting of a large rigid molecule that possesses two water-solubilizing sulfates on one face and an extended hydrophobic surface on the other. The properties of this compound have been examined by X-ray analysis, light and cryo-electron microscopy, surface tension, conductivity, microrheology, and NMR. Aqueous solutions behave quite differently from those of a conventional amphiphile with long linear and flexible chains (e.g., sodium dodecyl sulfate). Thus, there is evidence that the facial amphiphile self-assembles to form viscous networks, but without the traditional critical micelle concentration, as if assembly is a stepwise process. Emulsions of toluene in water promoted by the facial amphiphile are stable for many months. In contrast to conventional surfactants, the NMR peaks are obliterated in aqueous solutions of the facial amphiphile. Both X-ray and cryo-HRSEM data suggest a lamellar morphology.