Symmetric di- or tetra-alkyl substituted monodisperse polyoxyethyleneglycols: Synthesis and surface properties

A new series of amphiphilic compounds are presented. The dialkylated monodisperse polyoxyethylene derivatives were prepared by a three-step reaction and global yields >60% were obtained. For the synthesis of the tetraalkylated derivatives, six reaction steps were required and yields >40% were obtained. The evaluation of their surface properties was effected by measuring the variation of the surface tension (γ) of the aqueous solutions as a function of their concentration. The results reveal that they are surface-active agents. They lowered the surface tension of water to the range usually observed for classical hydrogenated non-ionic surfactants. The observed stabilization of γ for a range of concentrations corresponds to the formation of organized phases. The Critical Concentrations obtained are higher than those for analogous linear compounds having the same hydrophilic-lipophilic balance. The areas per polar head group of surfactant molecules are relatively constant for compounds of equivalent hydrophobicity.