Proton conductivity and proton dynamics in nanocrystalline cellulose functionalized with imidazole

J Tritt-Goc; Ł Lindner; M Bielejewski; E Markiewicz; R Pankiewicz

doi:10.1016/j.carbpol.2019.115196

Proton conductivity and proton dynamics in nanocrystalline cellulose functionalized with imidazole

Carbohydr Polym. 2019 Dec 1:225:115196. doi: 10.1016/j.carbpol.2019.115196. Epub 2019 Aug 13.

Authors

J Tritt-Goc¹, Ł Lindner², M Bielejewski³, E Markiewicz⁴, R Pankiewicz⁵

Affiliations

¹ Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. Electronic address: jtg@ifmpan.poznan.pl.
² Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. Electronic address: lukasz.lindner@ifmpan.poznan.pl.
³ Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. Electronic address: bielejewski@ifmpan.poznan.pl.
⁴ Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. Electronic address: ewa.markiewicz@ifmpan.poznan.pl.
⁵ Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland. Electronic address: radek@px.pl.

PMID: 31521266
DOI: 10.1016/j.carbpol.2019.115196

Abstract

In the present study, we report the synthesis, electrical and dynamic properties of a new generation bio-based nanocomposite, that is a proton-exchange membrane based on nanocrystalline cellulose (CNC) and imidazole (Im). CNC serves as supporting material and imidazole acts as a proton donor and proton acceptor at the same time. The nanocomposite (1.3 CNC-Im) was synthesized as a film and shows proton conductivity equal to 4.0 × 10^-1 S/m at 160 °C in anhydrous conditions. Analysis of impedance measurements and NMR spectra provided some insight into the macroscopic and microscopic processes involved in proton transport in 1.3 CNC-Im. Local processes such as reorientation of imidazole rings and breaking of hydrogen bonds are identified and their activation energies are calculated. The energies of the macroscopic and microscopic proton transport in CNC-Im film are correlated. The percolation model used confirmed the percolation nature of conductivity in cellulose composites with imidazole.

Keywords: Electrical conductivity; Imidazole-doped nanocrystalline cellulose; NMR; Percolation model; Proton and imidazole dynamics.