Molecular Motion of Polyethylene Oxide in Dilute Aqueous and Non-aqueous Solutions

Neutron scattering measurements on dilute solutions, aqueous and nonaqueous, of polyethylene oxide are reported. No interaction of a hydrophobic or hydrophilic nature is detected in water. The spectra from polyethylene oxide molecules over almost the whole momentum transfer region can be explained in terms of Langevin diffusion models both for the translational and the rotational motion. At small momentum transfers (x < 0.5 A-1) another molecular motion involving large amplitudes and small characteristic times should be included. This unknown motion may involve conformational changes of the molecule but also spontaneous fluctuations of its long axis.