Dynamical aspects of water-poly(ethylene glycol) solutions studied by 1H NMR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This paper describes the results of a detailed investigation on the dynamic behavior of poly( ethylene glycol), PEG, with low molar mass (200, 300, 400 and 600 g moL(-1)) and water in all ranges of concentrations. The study is based on spin-spin (T-2), spin-lattice (T-1) relaxation times and on the variations of the proton chemical shift. The relaxations of the exchangeable and non-exchangeable hydrogen atoms depend on the mobility of the molecules of the solutions. Therefore, the results of T-1 and T-2 allow one to determine the transitions between the dilute, semi-dilute and concentrate polymeric regimes, and they were well correlated with the kinematic viscosity of the solutions. The distribution of water molecules between the ethylene oxide and the terminal hydroxyl groups of PEG in the entire regime was investigated by using high-field NMR, and the characteristic average number of water molecules belonging to the hydration layer of PEG was also determined. (C) 2016 Elsevier B.V. All rights reserved.This paper describes the results of a detailed investigation on the dynamic behavior of poly(ethylene glycol), PEG, with low molar mass (200, 300, 400 and 600 g mol− 1) and water in all ranges of concentrations. The study is based on spin–spin (T2), spin–22294100Brazilian agency CNPq [153228/2014-8, 301016/2015-1]PETROBRAS [0050.0022719.06.4/4600322789]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq