Synthesis, Surface Activity and Application Properties of a Novel Ethoxylated Gemini Trisiloxane Surfactant

A novel ethoxylated gemini trisiloxane surfactant B whose general formula is of RO(CH2CH2O)(8.7)R [R = Me3SiOSiMe(CH2)(3)center dot OSiMe3] has been synthesized using polyethylene glycol 400, 3-chloropropylene and 1,1,1,3,5,5,5-heptamethyltrisiloxane as main raw materials. This compound was structurally characterized by ESI-MS, H-1-NMR and C-13-NMR spectroscopy. Its surface activity and application properties containing spreading performance and hydrolysis resistance were also measured. The critical aggregation concentration (CAC) and the surface tension of surfactant B solution at CAC (gamma(CAC)) of are 2.63 x 10(-6) mol L-1 and 20.7 mN m(-1), respectively. This CAC is only one-tenth of the CAC of the Y-shaped ethoxylated double-tail trisiloxane surfactant 1P, where CAC was replaced with critical micelle concentration (CMC), indicating that surfactant B has an extremely high surface activity. The spreading ability (SA) of its solution (5 x 10(-3) mol L-1) within 1 min over Parafilm, PE film and ficus microcarpa leaves is 23.9, 45.7 and 59.8, respectively, suggesting that this surfactant has a better SA than 1P and possesses superspreading. This surfactant also possesses a stronger hydrolysis resistance than 1P; for instance, in pH 10.0 environment for 86 days. The surface tension of surfactant B solution has been no more than 6 percent of its initial value. It is suggested that the excellent interfacial properties of surfactant B is related to its U-shaped conformation in water.