Dynamic properties of aqueous solutions of ethylene glycol oligomers as measured by the pulsed gradient spin-echo NMR technique at 25[deg ]C

Abstract

Self-diffusion coefficients for binary systems containing water and an oligomer of ethylene glycol [HO–(CH₂CH₂–O)_nH, n=1–5], have been measured at 25°C in the whole concentration range by the pulsed gradient spin-echo NMR technique. Upon adding oligomer to pure water, both the oligomer and water self-diffusion coefficients decrease until a certain composition is reached, after which they remain approximately constant. This evidence is interpreted in terms of molecular interactions, especially hydrogen-bond formation. A relation between mutual and self-diffusion coefficients for these systems is found and commented upon.