Polyglycerol modified polysiloxane surfactants: Their adsorption and aggregation behavior in aqueous solution

A simple process to synthesize polyglycerol modified polysiloxane surfactants has been carried out applying a “grafting-to” approach. After formation of allyl polyglycerol ether (APGE) from diglycerol (DGY) and allyl glycidyl ether (AGE), polysiloxane modified by designed number of polyglycerol groups (PHMS-APGE) were obtained by connecting the APGE structure to different SiH functionalized polyhydromethyl siloxane (PHMS). The synthesized APGE-PHMS were characterized by IR and 1H NMR. Solubility measurements showed that the solubility of the as-prepared polymers increased in polar solvents with the increasing of the amount of hydrophilic APGE groups. Furthermore, the surface activity, surface adsorption, aggregation and spreading behaviors of APGE-PHMS were investigated utilizing surface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM) and contact angle measurements. The results showed that critical aggregation concentration (CAC) and the time needed to reach adsorption equilibrium on water surface decrease systematically with the increase in the number of APGE groups. These polymers in aqueous solutions could aggregate to form spherical assemblies. Moreover, the spreading behavior of these polymers on low energy surface was found to be influenced by the number of hydrophilic APGE groups.