Molecular motions in poly(ethylene oxide) solutions

The motions of solvent and molecules in solutions of poly(ethylene oxide) have been investigated by neutron inelastic scattering measurements. Both the concentration dependence and the influence of the molecular weight of the PEO molecules were studied. It is shown that there exists a strong concentration dependent interaction between a PEO molecule and the surrounding water which affects both the translational and the rotational motions of the water molecules. Thus there is a clear indication of the presence of a hydration shell around each PEO molecule within which the motions of the water molecules are strongly hindered. In carbon tetrachloride solutions the results indicate that there exists a weak interaction of hydrodynamic origin between solvent and solute molecules.