Synthesis and properties of sodium carboxylate silicone surfactant via thiol-ene “click” reaction

The sodium carboxylate silicone surfactant (Si4-COONa)was synthesized via thiol-ene "click" reaction. Its chemical structure was confirmed by 1H NMR, and ESI-MS. The surface activity and aggregation behavior in aqueous solution were investigated by electrical conductivity, surface tension, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Si4-COONa exhibited admirable surface activity and could reduce the water's surface tension to 19.4 mN·m−1. The electrical conductivity showed that the counterion binding value of Si4-COONa increases with increasing temperature. By analyzing the thermodynamic parameters of micellization, it was found that the micellization of Si4-COONa is spontaneous and entropy driven. The addition of inorganic and organic salts in the aqueous solution decreases the critical micelle concentration remarkably. The TEM and DLS results indicated that the Si4-COONa in aqueous solution or salts solution formed spherical aggregates above the critical micelle concentration.