Solution properties of homogeneous polyglycerol dodecyl ether nonionic surfactants

The synthesis and solution properties of a homologous series of polyglycerol dodecyl ethers (R₁₂G_n) 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 (R₁₂EO_n). The surface tension measurements showed that R₁₂G_n have sufficiently low values of surface tension and critical micellization concentration (cmc) to serve as useful nonionic surfactants. The mesophases appearing in the R₁₂G_n systems were more stable in a high temperature range than the mesophases of the R₁₂EO_n 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 R₁₂G_n/dodecane/water systems showed that the solubilizing and emulsifying powers of R₁₂G_n were greater than those of R₁₂EO_n. It is concluded that the polyglycerol chain can be even more useful as the hydrophilic part of nonionic surfactants than the conventional oxyethylene chain.