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

Abstract

AbstractA novel ethoxylated gemini trisiloxane surfactant B whose general formula is of RO(CH2CH2O)8.7R [R = Me3SiOSiMe(CH2)3 · 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, 1H-NMR and 13C-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 (γCAC) of are 2.63 × 10−6 mol L−1 and 20.7 mN m−1, respectively. This CAC is only one-tenth of the CAC of the Υ-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 × 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.