Solution properties of homogeneous polyglycerol dodecyl ether nonionic surfactants

The synthesis and solution properties of a homologous series of polyglycerol dodecyl ethers (R12Gn) are described. The phase behavior, surface tension, cloud point and HLB value (hydrophile lipophile balance) of these surfactants in aqueous solutions and in mixed solutions of water/oil have been investigated and compared with values for polyoxyethylene dodecyl ether (R12EOn). The surface tension measurements showed that R12Gn have sufficiently low values of surface tension and critical micellization concentration (cmc) to serve as useful nonionic surfactants. The mesophases appearing in the R12Gn systems were more stable in a high temperature range than the mesophases of the R12EOn systems. The cloud point and HLB data indicated that addition of one glycerol group was equivalent to the addition of three oxyethylene units, as far as the hydrophilic property was concerned. The phase diagrams of the R12Gn/dodecane/water systems showed that the solubilizing and emulsifying powers of R12Gn were greater than those of R12EOn. It is concluded that the polyglycerol chain can be even more useful as the hydrophilic part of nonionic surfactants than the conventional oxyethylene chain.