Abstract
Ion dynamics in a series of imidazolium-based triblock copolymers (triblock co-PILs) are investigated using broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC) and compared to their homopolymer counterparts (homo-PILs). Two calorimetric glass transition temperatures (T g ) are observed corresponding to the charged poly(ionic liquid) (PIL) blocks and noncharged polystyrene (PS) blocks. Varying the counterion from Br - to NTf2 decreases the T g of the charged block by over 50 °C, thereby increasing the room-temperature ionic dc conductivity by over 6 orders of magnitude. Interestingly, for a given anion, varying the volume fraction of the charged block, from ∼0.5 to ∼0.8, has very minimal effect on the dc ionic conductivity, indicating that the choice of counterion is the key factor influencing charge transport in these systems.
Original language | English |
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Pages (from-to) | 620-628 |
Number of pages | 9 |
Journal | Macromolecules |
Volume | 52 |
Issue number | 2 |
DOIs | |
State | Published - Jan 22 2019 |
Funding
This manuscript has been authored by UT-Battelle, LLC, under Contract DE-AC05-00OR22725 with the U.S. Department of Energy. E.U.M., M.A.H., and M.F.H. are grateful for financial support by the National Science Foundation, Division of Materials Research, Polymers Program, through DMR-1508394. J.S. gratefully acknowledges partial support from the U.S. Army Research Office under Contract W911NF-17-1-0052. This research was suported by Oak Ridge National Laboratory’s (ORNL) Laboratory Directed Research and Development Program. A portion of this work was conducted at the Center for Nanophase Materials Sciences, which is a US Department of Energy Office of Science User Facility. This work is also supported by the US National Science Foundation under Award DMR 1507764.