Diffusion Behavior of Methanol Molecules Confined in Cross-Linked Phenolic Resins Studied Using Neutron Scattering and Molecular Dynamics Simulations

The dynamics of methanol confined in highly cross-linked phenolic resins was investigated using incoherent quasielastic neutron scattering (QENS) and atomistic molecular dynamics (MD) simulations. The QENS analysis for a deuterated phenolic resin and both deuterated and nondeuterated methanol indicated the presence of resin dynamics induced by methanol invasion and confined diffusion of the methanol molecules. QENS results suggested that methanol had a diffusion coefficient of 1.6 × 10–6 cm2/s, which is 1 order of magnitude smaller than the bulk value (2.3 × 10–5 cm2/s). The MD trajectories also showed that the methanol diffusion was limited by the resin network, consistent with QENS results in terms of the diffusion coefficient and diffusion-like behavior.