Charge transport, thermodynamics, and hydrodynamics in side-chain and main-chain polymerized ionic liquids

• Applicant: Dr. Catalin Gainaru
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Experimental Condensed Matter Physics
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 396060266

• Final Report Year: 2021

Final Report Abstract

Within the framework of the current project, we investigated a large number of electrically conducting materials including classical ionic liquids, oligomeric and polymeric electrolytes, and more “exotic” systems such aqueous solutions, deep eutectic solvents and acid hydrates, by means of dielectric spectroscopy, shear rheology, calorimetry, and NMR. Our results demonstrated that ionic liquids can be considered as model systems with charge dynamics governed by the structural rearrangements, while n other systems such as PolyILs, ionic melts, and acid hydrates the charge and momentum (mass) transport are dynamically decoupled. We demonstrated that, studying independently the dielectric and the mechanical spectral shape of these materials one cannot gain any information regarding their structural individualities, as all the corresponding response functions are very similar among each other. Our studies revealed that the dynamical changes (mainly governed by the change in the glass transition temperature) induced by H-bonding in ILs can be significantly larger than those attributed to the changes of ion sizes. Thus, controlling the H-bonding ability of these liquids can be technologically much more relevant than simply varying their morphological composition. Based on the emerging of the decoupling phenomenon in PolyILs, we shown that their strong charge cross-correlation cannot be explained by the popular picture of ion-pair formation, since the long-range migration of such aggregates is impeded by the large dynamical contrast between their anions and cations. Considering the perspective of these materials being exploited in nanobattery technology, we also investigated their behavior under large electric fields, revealing the presence of a transient dissipation of electric energy governed by the local rearrangement of the polymeric segments. In collaboration with our research partners, we proposed that two critical mechanisms control the ionic mobility and its decoupling from segmental dynamics in PolyILs, namely the Coulombic and the elastic interactions, striving for a general picture of the conductivity mechanisms in polymeric electrolytes.

Publications

• Fundamental limitations of ionic conductivity in polymerized ionic liquids, Macromolecules 51, 8637 (2018)
  Stacy E., Gainaru C., Gobet M., Wojnarowska Z., Bocharova V., Greenbaum S., Sokolov A.
  
• Transient nonlinear response of dynamically decoupled ionic conductors, Phys. Rev. Lett. 121, 064503/1-6 (2018)
  Wieland F., Sokolov A. P., Böhmer R., Gainaru C.
  
• Deeply supercooled aqueous LiCl solution studied by frequency-resolved shear rheology, J. Chem. Phys. 150, 234505 (2019)
  Münzner P., Hoffmann L., Böhmer R., Gainaru C.
  
• Local and global dynamics of the viscous ion conductors 2Ca(NO3)2-3KNO3 and 2Ca(NO3)2-3RbNO3 probed by 87Rb nuclear magnetic resonance and shear rheology, J. Chem. Phys. 150, 194503 (2019)
  Beerwerth J., Bierwirth S. P., Adam J., Gainaru C., Böhmer R.
  
• Structure and dynamics of short-chain polymerized ionic liquids, J. Chem. Phys. 151, 034903 (2019)
  Wieland F., Bocharova V., Münzner P., Hiller W., Sakrowski R., Sternemann C., Böhmer, R., Sokolov A., Gainaru C.
  
• Modulation of Cation Diffusion by Reversible Supramolecular Assemblies in Ionic Liquid-Based Nanocomposites, ACS Appl. Mater. Interfaces 12, 31842 (2020)
  Bocharova V., Jayakody N., Yang J., Sacci R. L., Yang W., Cheng S., Doughty B., Greenbaum S., Jeong S. P., Popov I., Zhao S., Gainaru C., Wojnarowska Z.
  
• Strongly Correlated Ion Dynamics in Plastic Ionic Crystals and Polymerized Ionic Liquids, J. Phys. Chem. C 124, 17889 (2020)
  Popov I., Biernacka K., Zhu H., Nti F., Porcarelli L., Wang X., Khamzin A., Gainaru C., Forsyth M., Sokolov A. P.
  
• Tuning the dynamics of imidazolium-based ionic liquids via hydrogen bonding I. The viscous regime, J. Chem. Phys. 153, 194501 (2020
  Thomann C. A., Münzner P., Moch K., Jacquemin J., Goodrich P., Sokolov A. P., Böhmer R., Gainaru C.
  
• The relationship between charge and molecular dynamics in viscous acid hydrates”, J. Chem. Phys. 155, 014505 (2021)
  Ahlmann S., Münzner P., Moch K., Sokolov A. P., Böhmer R., Gainaru C.
  
• Translational and reorientational dynamics in deep eutectic solvents, J. Chem. Phys. 154, 154501 (2021)
  Reuter D., Münzner P., Gainaru C., Lunkenheimer P., Loidl A., Böhmer R.