Self-motion of protons in the α-relaxation of poly(vinyl ethylene): a neutron scattering and MD-simulation study

The hydrogen motion in poly(vinyl ethylene) in the α-relaxation regime has been studied by combining neutron spin echo measurements on a fully protonated sample and molecular dynamics simulations. A crossover from Gaussian to non-Gaussian behavior is observed for the intermediate scattering function obtained, which takes place at relatively low Q-values. After validating the simulations by comparison with experiment, the motion of the different protons (side groups and main chain) can be isolately studied, providing useful information for interpreting the experimental results