Hydration Numbers of Polyethylene Glycols Based on a New Viscosity Model

Abstract

AbstractDue to the high solubility in water and the structural compatibility of polyethylene glycol with water molecules, it is a good model system for studying the mechanisms of interaction between water and biopolymers. The behavior of biopolymers in living organisms strongly depends on the hydration of macromolecules in the aquatic environment. In this work the effective hydration numbers of polyethylene glycols are determined using a new viscosity model developed for electrolytes and experimental data on the viscosity of dilute aqueous solutions of polyethylene glycols (300–35000). The calculated hydration numbers are in good agreement with the literature data and increase with increasing molecular mass of polyethylene glycol: as the molecular mass increases, starting from a molecular mass of 1000, the chain begins to fold in on itself, forming segment‐segment interactions, trapping additional, more loosely bound water between the segments. Based on the dependence of the intrinsic viscosity on the molecular mass according to the Mark‐Houwink equation, it is shown that PEGs are the flexible polymers and highly soluble in water.