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

Abstract

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.