| Gemini or dimeric surfactants, which are made up of two single-chain surfactants joined by a spacer at or near the head group have gained much attention, as these novel surfactants have many unique properties that are superior to those of their monomers, such as remarkably low critical micelle concentrations (cmc), much higher efficiency, in regard to reducing surface tensions, unusual aggregation morphologies, and better wetting, solubilizing, and foaming properties, which make them potentially useful in many applications.To date the majority of gemini surfactant studies have been on ionic systems, and nonionic gemini surfactant gets less attraction. With these considerations we have synthesized a series of nonionic gemini surfactants, ethoxylated hydroquinone bislauryl alcohol, referred as HBA(EO)n(n=9,20,80). The surface properties, such as critical micelle concentration, cmc, the minimum surface tension,γcmc, surface excess concentration,Γcmc, and surface area per molecule, Amin have been determined by means of surface tension measurements. Effects of salt and pH on the surface properties of HBA(EO)80 aqueous solution systems were investigated. Cmcs of two mixed system, nonionic gemini mixed with anionic Gemini (C11p-PHCNa/HBA(EO)80)and nonionic gemini mixed with anionic monomeric (SL/HBA(EO)80) and the effect of salt on the two mixed system were investigated. FF-TEM (Freeze-Fracture Transmission Electron Microscope), Negative-staining TEM and SEM (Scanning Electron Microscope) were used to investigate the mixed aggregates' morphologies.The results show that HBA(EO)n (n=9,20,80) series have rather higher surface properties in comparison to their monomeric counterparts. In the HBA(EO)80 system globular Vesicles formed which is quite interesting by the different elect- ron microscopy methods. Both C11pPHCNa/HBA(EO)80 and SL/HBA(EO)80 mixed systems have remarkable synergistic behavior. With the NaC1 concentration increases the values Ofγcmc and CMC decrease in the two mixed systems. Large spherical aggregates both were formed in the two mixed system, which trend to transfer into micelies with the increases of the salt concentration. The results show that the salt effect is quite strong in the two mixed systems.
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