Charge Transport and Glassy Dynamics in Blends Based on 1-Butyl-3-vinylbenzylimidazolium Bis(trifluoromethanesulfonyl)imide Ionic Liquid and the Corresponding Polymer

Abstract

Charge transport, diffusion properties, and glassy dynamics of blends of imidazolium-based ionic liquid (IL) and the corresponding polymer (polyIL) were examined by Pulsed-Field-Gradient Nuclear Magnetic Resonance (PFG-NMR) and rheology coupled with broadband dielectric spectroscopy (rheo-BDS). We found that the mechanical storage modulus (G′) increases with an increasing amount of polyIL and G′ is a factor of 10,000 higher for the polyIL compared to the monomer (GIL′= 7.5 Pa at 100 rad s−1 and 298 K). Furthermore, the ionic conductivity (σ0) of the IL is a factor 1000 higher than its value for the polymerized monomer with 3.4×10−4 S cm−1 at 298 K. Additionally, we found the Haven Ratio (HR) obtained through PFG-NMR and BDS measurements to be constant around a value of 1.4 for the IL and blends with 30 wt% and 70 wt% polyIL. These results show that blending of the components does not have a strong impact on the charge transport compared to the charge transport in the pure IL at room temperature, but blending results in substantial modifications of the mechanical properties. Furthermore, it is highlighted that the increase in σ0 might be attributed to the addition of a more mobile phase, which also possibly reduces ion-ion correlations in the polyIL.

1,3,4,5‐Tetrasubstituted Poly(1,2,3‐triazolium) Obtained through Metal‐Free AA+BB Polyaddition of a Diazide and an Activated Internal Dialkyne

“…Above T g , the dependence of σ DC with reciprocal temperature ( Figure ) follows a Vogel–Fulcher–Tammann behavior, since the charge transport of the TFSI anions above T g depends on the segmental mobility of the polymer chains. [ 60–62 ] The experimental results were thus fitted using Equation () $$$$\begin{equation}\ {\sigma }_{{\mathrm{DC}}} = {\sigma }_\infty \ \times \ {\mathrm{exp}}\left( { - \frac{B}{{\left( {T - {T}_0} \right)}}} \right)\end{equation}$$$$with σ ∞ the ionic conductivity in the high temperature limit, B a fitting parameter related to the activation energy of the ionic conduction, and T 0 the Vogel temperature. The different substituents in the C‐4/C‐5 positions (H or CH 3 for 6 and 7 , respectively) have a moderate impact on the level of ionic conductivity ( σ DC = 2.7 × 10 −6 and 2.0 × 10 −6 S cm −1 at 30 °C and under anhydrous conditions, respectively) in accordance with their comparable T g values ( T g = −21 and −23 °C, respectively).…”

“…Above T g , the dependence of 𝜎 DC with reciprocal temperature (Figure 3) follows a Vogel-Fulcher-Tammann behavior, since the charge transport of the TFSI anions above T g depends on the segmental mobility of the polymer chains. [60][61][62] The experimental results were thus fitted using Equation ( 1)…”