Synthesis and Surface Properties of Polyether-Based Silicone Surfactants with Different Siloxane Groups

A series of polyether-based silicone surfactants with different hydrophobic chains (trimethylsiloxy, triethylsiloxy, and triisopropylsiloxy) were synthesized. The molecular structures were confirmed using H-1 nuclear magnetic resonance (NMR), C-13 NMR, Si-29 NMR, and fourier transform infrared spectroscopy (FT-IR). The effect of the siloxane groups on the physicochemical properties, surface tension (gamma), critical micelle concentration (CMC), surface tension at the CMC (gamma(CMC)), adsorption efficiency (pC(20)), surface pressure at the CMC (pi(CMC)), maximum surface excess (Gamma(max)), single silicone surfactant molecule at the air/water interface (A(min)), and the standard free energy of adsorption (Delta Gads0), of the polyether-based silicone surfactants was investigated. Results indicate that the polyether-based silicone surfactants can reduce the surface tension of water to approximately 25-31 mN m(-1) and the surface activity of silicone surfactants is enhanced with increasing branched trimethylsiloxyl and sterically hindered siloxane groups.