Syntheses, Characterization And Application Of Novel Gemini Surfactants

In this paper, we synthesized six sulfonate-containing gemini surfactants: sodium1,1′-(biphenyl-4,4′-diyl)bis(1-oxoalkane-2-sulfonate)8H-L and12H-L, sodium1,1′-(4,4′-methylenebis(1,4-phenylene))bis(1-oxoalkane-2-sulfonate)8H-J and12H-J, sodium1,1′-(4,4′-(ethane-1,2-diyl)bis(1,4-phenylene))bis(1-oxoalkane-2-sulfonate)8H-Y and12H-Y. All the spacers of these gemini surfactants contained two rigid benzene rings and two rigid carbonyl groups.1. These gemini surfactants were characterized by1H-NMR、 electrosprayionization/mass spectrometry (ESI-MS) and Fourier transform infrared (FTIR).2. The surface properties of these new gemini surfactants measured bytensiometer and the aggregation behavior of them in water was investigated usingdynamic light scattering (DLS) and transmission electron microscopy(TEM).Comparing with conventional single-chain surfactant sodium dodecylsulfonate (SDS),all the gemini surfactants synthesized have lower cmc and C20values, suggesting anexcellent micelle forming ability of these gemini surfactants in water and remarkableefficiency at decreasing the surface tension of water. The influence of spacer lengthand hydrophobic chain on the surface properties of gemini surfactant was studied. Theresults show that the cmc or C20value decreases upon increasing the spacer orhydrophobic chain length.3. The suspensions of Multi-walled carbon nanotubes (MWCNTs), dispersed by8H-L or Sodium1-octanesulfonate, were prepared by sonicated for10min in waterbath at100W and40kHz. Comparing with conventional single-chain surfactantSodium1-octanesulfonate,8H-L exhibited much higher properties when dispersingand stabilizing the MWCNTs in aqueous solutions. The effect of the concentration of8H-L, the concentration of MWCNTs and sonication time on the dispersion ofMWCNTs in aqueous solution was investigated. The results show that highconcentration of8H-L, high concentration of MWCNTs in aqueous solution or alonger sonication time leads to a higher concentration of MWCNTs in solution.