Institution: | 1. Institute of Chemical Physics, Vilnius University, Vilnius, Lithuania
Department of Chemistry, University of Southampton, Southampton, UK;2. Institute of Chemistry, Vilnius University, Vilnius, Lithuania;3. Institute of Chemical Physics, Vilnius University, Vilnius, Lithuania
Eduard-Zintl Institute for Inorganic and Physical Chemistry, University of Technology Darmstadt, Darmstadt, Germany;4. Institute of Applied Electrodynamics and Telecommunications, Vilnius University, Vilnius, Lithuania;5. Institute of Chemical Physics, Vilnius University, Vilnius, Lithuania |
Abstract: | The 1H–13C cross-polarization with magic-angle spinning (CP MAS) kinetics was studied in poly(methacrylic acid) (PMAA) having the purpose to track the links between the local order in the main chain and the proton dynamics in peripheral hydrogen bond networks. The experimental CP MAS kinetic curves were analyzed applying the models of isotropic and anisotropic spin-diffusion with thermal equilibration. The fractal dimension Dp ≈ 3 was deduced that indicates that PMAA behaves as an isotropic 3D-system. No proton conductivity in the neat PMAA was deduced from the impedance spectroscopy data analyzing the frequency dependences of the complex dielectric permittivity. The value of local order parameter S = 0.70 for CH2 in PMAA occupies an intermediate position between 0.63 and 0.85 deduced for CH2 sites in the main chains of poly(vinyl phosphonic acid) and poly(2-hydroxyethyl methacrylate), that is, the true proton conductor and the polymer that contains the H-bond network, however, no proton conductivity, respectively. |