Measurement of Surface Tension and Electrical Conductivity of Cationic Gemini Surfactants

Three kinds of cationic Gemini surfactants (C12H25N(CH3)2—CnH2n—(CH3)2NC12H25,2Br-1)(n=3,4,6) have been synthesized. Surface tension and electrical conductivity of their aqueous solutions at different concentration have been measured. From these experimental data, the critical micelle concentration (CMC), excess adsorption amount at vaporliquid interface, the area per molecule and the degree of ionization of micelle have been obtained. Results show that Gemini surfactants have much lower CMC and stronger surface activity comparing with the corresponding monomeric conventional surfactants. The spacer group has a great influence on the properties of aqueous Gemini surfactants.