Synthesis, characterization and surface properties of novel polyether based siloxane surfactants

Abstract

A series of poly(ethylene glycol) based trisiloxane or tetrasiloxane surfactants have been synthesized via thiol-ene reaction and confirmed by 1H NMR, 13C NMR, 29Si NMR, and FT-IR. The effect of the trimethylsiloxy groups and length of the ethylene glycol (EO) chain on the physicochemical properties, surface tension (γ), critical micelle concentration (CMC), surface tension at the CMC (γcmc), adsorption efficiency (pC20), surface pressure at the CMC (πCMC), maximum surface excess (Γmax), single siloxane surfactant molecule at the air/water interface (Amin), and the standard free energy of adsorption (), of these polyether based siloxane surfactants was investigated by surface tension, DLS, and TEM measurement. It indicated that all investigated polyether based siloxane surfactants can reduce the surface tension of water to approximately 21–24 mN·m−1 and the surface activities of silicone surfactants were enhanced with increasing the branched trimethylsiloxy groups and length of the EO chain.