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Cross‐polarization with magic‐angle spinning kinetics and impedance spectroscopy study of proton mobility, local disorder, and thermal equilibration in hydrogen‐bonded poly(methacrylic acid)
Author(s) -
Dagys Laurynas,
Klimkevičius Vaidas,
Klimavicius Vytautas,
Balčiūnas Sergejus,
Banys Jūras,
Balevicius Vytautas
Publication year - 2020
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200592
Subject(s) - dielectric spectroscopy , poly(methacrylic acid) , magic angle spinning , proton , materials science , anisotropy , hydrogen bond , chemistry , methacrylic acid , polymer chemistry , polymer , nuclear magnetic resonance spectroscopy , copolymer , molecule , organic chemistry , composite material , physics , electrochemistry , electrode , quantum mechanics
The 1 H– 13 C 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 D p ≈ 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 CH 2 in PMAA occupies an intermediate position between 0.63 and 0.85 deduced for CH 2 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.