Computational Simulations. In order to gain atomic-level insight into the dynamics occurring at terahertz frequencies in the hydrated materials, ab initio molecular dynamics (AIMD) and solid-state density functional theory (DFT) simulations were performed with CP2k. For the AIMD simulations, an initial simulation box containing eight symmetry independent polymer chains, each of which contained four polymer subunits, for a total of 608 independent atoms per cell. The system was subsequently hydrated to a 10% w/w concentration by randomly introducing 20 water molecules based on a minimum van der Waals radius cutoff methodology. The resulting system was equilibrated within the isothermal-isobaric (NPT) ensemble for 50 ps, which resulted in a bulk structure that strayed from crystallinity, at which point the canonical ensemble (NVT) was used in order to generate an infrared spectrum. The presented IR spectra are a result of taking the Fourier transform of the dipole moment autocorrelation function.